diff --git a/.gn b/.gn
index 33179129c..874f695a8 100644
--- a/.gn
+++ b/.gn
@@ -35,6 +35,9 @@ default_args = {
   # PDFium does not include the temporal_rs library.
   v8_enable_temporal_support = false
 
+  # PDFium does not use ICU4X implementations for ECMA-402 features.
+  v8_enable_ecma402_icu4x = false
+
   # PDFium has its own unsafe-buffers enforcement directories.
   clang_unsafe_buffers_paths = "//unsafe_buffers_paths.txt"
 
diff --git a/DEPS b/DEPS
index 2baa91ef5..1d0314ab3 100644
--- a/DEPS
+++ b/DEPS
@@ -102,7 +102,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling catapult
   # and whatever else without interference from each other.
-  'catapult_revision': 'e1165abbf12a3d9ecf2d3151a404c930b5047894',
+  'catapult_revision': 'c29dedc30c9ff1b0cc677e32a9a959ad5ed41bde',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling clang format
   # and whatever else without interference from each other.
@@ -134,7 +134,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling fast_float
   # and whatever else without interference from each other.
-  'fast_float_revision': 'b0ab987b3dfdde13fa1915f65ef2a5c068d9208c',
+  'fast_float_revision': '42f254836ee416ffcf2f4e6576260003ac33d48c',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling fp16
   # and whatever else without interference from each other.
@@ -154,7 +154,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling gtest
   # and whatever else without interference from each other.
-  'gtest_revision': '4fe3307fb2d9f86d19777c7eb0e4809e9694dde7',
+  'gtest_revision': '0b656495436f57212be8700794a3d5fb14000c5f',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling HarfBuzz
   # and whatever else without interference from each other.
@@ -166,7 +166,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling icu
   # and whatever else without interference from each other.
-  'icu_revision': '5aa526207171ecadf31597f0980a7b7ad8872f33',
+  'icu_revision': 'a0ea93436c528ca316a6e698e483e258839101a5',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling instrumented_lib
   # and whatever else without interference from each other.
@@ -174,7 +174,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling jinja2
   # and whatever else without interference from each other.
-  'jinja2_revision': 'c3027d884967773057bf74b957e3fea87e5df4d7',
+  'jinja2_revision': 'fde3c16799bd5937e4f15aedc9037c89f96236b9',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling jpeg_turbo
   # and whatever else without interference from each other.
@@ -204,7 +204,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling llvm-libc
   # and whatever else without interference from each other.
-  'llvm_libc_revision': '14e51fd2cd7ec21294f18a3a0b2fc5339afea271',
+  'llvm_libc_revision': 'd8f2045008e230f3c5f50095d918c11f1997e477',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling markupsafe
   # and whatever else without interference from each other.
@@ -244,7 +244,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling skia
   # and whatever else without interference from each other.
-  'skia_revision': '0abfcf118530e0e46e7e466f6d028041af61581a',
+  'skia_revision': '607de4b035dcf7fdbaafb66c6cc04f22009ff4d4',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling test_fonts
   # and whatever else without interference from each other.
@@ -264,15 +264,15 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling tools_win_revision
   # and whatever else without interference from each other.
-  'tools_win_revision': 'ae34cdd9867c5d2b185fadc9d4a9cc82bb741760',
+  'tools_win_revision': 'd72db9e3040567a7589e00c0ad7ddf25c3b070bc',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling v8
   # and whatever else without interference from each other.
-  'v8_revision': '0d546234ecf0af2032e958300ef8aeb14bc716c9',
+  'v8_revision': 'bb54fc4e853a1ef1640b160e5e854d0a3b514e29',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling zlib
   # and whatever else without interference from each other.
-  'zlib_revision': '456ae730017b9b4bd3371927abc82627fd51feef',
+  'zlib_revision': '9f9f52c60a14e8e772fb561029ae0a121fef7609',
 }
 
 # Only these hosts are allowed for dependencies in this DEPS file.
@@ -1005,31 +1005,13 @@ hooks = [
   },
   # Configure remote exec cfg files
   {
-    # Use luci_auth if on windows and using chrome-untrusted project
     'name': 'download_and_configure_reclient_cfgs',
     'pattern': '.',
-    'condition': 'download_remoteexec_cfg and host_os == "win"',
+    'condition': 'download_remoteexec_cfg',
     'action': ['python3',
                'buildtools/reclient_cfgs/configure_reclient_cfgs.py',
                '--rbe_instance',
                Var('rbe_instance'),
-               '--reproxy_cfg_template',
-               'reproxy.cfg.template',
-               '--rewrapper_cfg_project',
-               Var('rewrapper_cfg_project'),
-               '--use_luci_auth_credshelper',
-               '--quiet',
-               ],
-  },  {
-    'name': 'download_and_configure_reclient_cfgs',
-    'pattern': '.',
-    'condition': 'download_remoteexec_cfg and not host_os == "win"',
-    'action': ['python3',
-               'buildtools/reclient_cfgs/configure_reclient_cfgs.py',
-               '--rbe_instance',
-               Var('rbe_instance'),
-               '--reproxy_cfg_template',
-               'reproxy.cfg.template',
                '--rewrapper_cfg_project',
                Var('rewrapper_cfg_project'),
                '--quiet',
@@ -1043,8 +1025,6 @@ hooks = [
                'buildtools/reclient_cfgs/configure_reclient_cfgs.py',
                '--rbe_instance',
                Var('rbe_instance'),
-               '--reproxy_cfg_template',
-               'reproxy.cfg.template',
                '--rewrapper_cfg_project',
                Var('rewrapper_cfg_project'),
                '--skip_remoteexec_cfg_fetch',
diff --git a/core/fpdfapi/edit/cpdf_image_redactor.cpp b/core/fpdfapi/edit/cpdf_image_redactor.cpp
index 9c6f391a6..f0fb9ab22 100644
--- a/core/fpdfapi/edit/cpdf_image_redactor.cpp
+++ b/core/fpdfapi/edit/cpdf_image_redactor.cpp
@@ -758,10 +758,9 @@ std::optional<Decoded> Decode(CPDF_Document* doc,
   // CPDF_DIB reads both only when it loads the image's mask.
   const bool load_mask = inline_alpha || matte;
   auto dib = pdfium::MakeRetain<CPDF_DIB>(doc, std::move(stream));
-  CPDF_DIB::LoadState state =
-      dib->StartLoadDIBBase(load_mask, resources, page_resources,
-                            /*bStdCS=*/false, CPDF_ColorSpace::Family::kUnknown,
-                            /*bLoadMask=*/load_mask, CFX_Size());
+  CPDF_DIB::LoadState state = dib->StartLoadDIBBase(
+      load_mask, resources, page_resources, CPDF_ColorSpace::Family::kUnknown,
+      /*bLoadMask=*/load_mask, CFX_Size());
   while (state == CPDF_DIB::LoadState::kContinue) {
     state = dib->ContinueLoadDIBBase(nullptr);
   }
diff --git a/core/fpdfapi/page/cpdf_basedcs.cpp b/core/fpdfapi/page/cpdf_basedcs.cpp
index 522b1ef8f..f67dbefaa 100644
--- a/core/fpdfapi/page/cpdf_basedcs.cpp
+++ b/core/fpdfapi/page/cpdf_basedcs.cpp
@@ -9,10 +9,3 @@
 CPDF_BasedCS::CPDF_BasedCS(Family family) : CPDF_ColorSpace(family) {}
 
 CPDF_BasedCS::~CPDF_BasedCS() = default;
-
-void CPDF_BasedCS::EnableStdConversion(bool bEnabled) {
-  CPDF_ColorSpace::EnableStdConversion(bEnabled);
-  if (base_cs_) {
-    base_cs_->EnableStdConversion(bEnabled);
-  }
-}
diff --git a/core/fpdfapi/page/cpdf_basedcs.h b/core/fpdfapi/page/cpdf_basedcs.h
index 55a16ad86..83746a189 100644
--- a/core/fpdfapi/page/cpdf_basedcs.h
+++ b/core/fpdfapi/page/cpdf_basedcs.h
@@ -18,8 +18,6 @@ class CPDF_BasedCS : public CPDF_ColorSpace {
   CONSTRUCT_VIA_MAKE_RETAIN;
   ~CPDF_BasedCS() override;
 
-  void EnableStdConversion(bool bEnabled) final;
-
  protected:
   explicit CPDF_BasedCS(Family family);
 
diff --git a/core/fpdfapi/page/cpdf_colorspace.cpp b/core/fpdfapi/page/cpdf_colorspace.cpp
index d3c0e8d02..8411cf493 100644
--- a/core/fpdfapi/page/cpdf_colorspace.cpp
+++ b/core/fpdfapi/page/cpdf_colorspace.cpp
@@ -136,7 +136,7 @@ class CPDF_CalGray final : public CPDF_ColorSpace {
                           int pixels,
                           int image_width,
                           int image_height,
-                          bool bTransMask) const override;
+                          bool is_transparency_mask) const override;
 
  private:
   static constexpr float kDefaultGamma = 1.0f;
@@ -161,7 +161,7 @@ class CPDF_CalRGB final : public CPDF_ColorSpace {
                           int pixels,
                           int image_width,
                           int image_height,
-                          bool bTransMask) const override;
+                          bool is_transparency_mask) const override;
   uint32_t v_Load(CPDF_Document* doc,
                   const CPDF_Array* pArray,
                   std::set<const CPDF_Object*>* pVisited) override;
@@ -195,7 +195,7 @@ class CPDF_LabCS final : public CPDF_ColorSpace {
                           int pixels,
                           int image_width,
                           int image_height,
-                          bool bTransMask) const override;
+                          bool is_transparency_mask) const override;
   uint32_t v_Load(CPDF_Document* doc,
                   const CPDF_Array* pArray,
                   std::set<const CPDF_Object*>* pVisited) override;
@@ -224,7 +224,7 @@ class CPDF_ICCBasedCS final : public CPDF_BasedCS {
                           int pixels,
                           int image_width,
                           int image_height,
-                          bool bTransMask) const override;
+                          bool is_transparency_mask) const override;
   bool IsNormal() const override;
   uint32_t v_Load(CPDF_Document* doc,
                   const CPDF_Array* pArray,
@@ -641,10 +641,9 @@ void CPDF_ColorSpace::TranslateImageLine(pdfium::span<uint8_t> dest_span,
                                          int pixels,
                                          int image_width,
                                          int image_height,
-                                         bool bTransMask) const {
-  // Only applies to CMYK colorspaces. None of the colorspaces that use this
-  // generic base implementation are CMYK.
-  CHECK(!bTransMask);
+                                         bool is_transparency_mask) const {
+  // Transparency masks are only used with CMYK colorspaces, not base CS.
+  CHECK(!is_transparency_mask);
 
   uint8_t* dest_buf = dest_span.data();
   const uint8_t* src_buf = src_span.data();
@@ -663,14 +662,6 @@ void CPDF_ColorSpace::TranslateImageLine(pdfium::span<uint8_t> dest_span,
   });
 }
 
-void CPDF_ColorSpace::EnableStdConversion(bool bEnabled) {
-  if (bEnabled) {
-    std_conversion_++;
-  } else if (std_conversion_) {
-    std_conversion_--;
-  }
-}
-
 bool CPDF_ColorSpace::IsNormal() const {
   return GetFamily() == Family::kDeviceGray ||
          GetFamily() == Family::kDeviceRGB ||
@@ -730,8 +721,9 @@ void CPDF_CalGray::TranslateImageLine(pdfium::span<uint8_t> dest_span,
                                       int pixels,
                                       int image_width,
                                       int image_height,
-                                      bool bTransMask) const {
-  CHECK(!bTransMask);  // Only applies to CMYK colorspaces.
+                                      bool is_transparency_mask) const {
+  // Transparency masks are only used with CMYK colorspaces, not CalGray.
+  CHECK(!is_transparency_mask);
 
   auto gray_span = src_span.first(static_cast<size_t>(pixels));
   auto rgb_span = fxcrt::reinterpret_span<FX_RGB_STRUCT<uint8_t>>(dest_span);
@@ -813,8 +805,9 @@ void CPDF_CalRGB::TranslateImageLine(pdfium::span<uint8_t> dest_span,
                                      int pixels,
                                      int image_width,
                                      int image_height,
-                                     bool bTransMask) const {
-  CHECK(!bTransMask);  // Only applies to CMYK colorspaces.
+                                     bool is_transparency_mask) const {
+  // Transparency masks are only used with CMYK colorspaces, not CalRGB.
+  CHECK(!is_transparency_mask);
   fxcodec::ReverseRGB(dest_span, src_span, pixels);
 }
 
@@ -904,8 +897,9 @@ void CPDF_LabCS::TranslateImageLine(pdfium::span<uint8_t> dest_span,
                                     int pixels,
                                     int image_width,
                                     int image_height,
-                                    bool bTransMask) const {
-  CHECK(!bTransMask);  // Only applies to CMYK colorspaces.
+                                    bool is_transparency_mask) const {
+  // Transparency masks are only used with CMYK colorspaces, not Lab.
+  CHECK(!is_transparency_mask);
 
   auto bgr_span = fxcrt::reinterpret_span<FX_BGR_STRUCT<uint8_t>>(dest_span);
   auto lab_span =
@@ -996,8 +990,9 @@ void CPDF_ICCBasedCS::TranslateImageLine(pdfium::span<uint8_t> dest_span,
                                          int pixels,
                                          int image_width,
                                          int image_height,
-                                         bool bTransMask) const {
-  CHECK(!bTransMask);  // Only applies to CMYK colorspaces.
+                                         bool is_transparency_mask) const {
+  // Transparency masks are only used with CMYK colorspaces, not ICCBased.
+  CHECK(!is_transparency_mask);
 
   if (profile_->IsSRGB()) {
     fxcodec::ReverseRGB(dest_span, src_span, pixels);
diff --git a/core/fpdfapi/page/cpdf_colorspace.h b/core/fpdfapi/page/cpdf_colorspace.h
index fb01643f2..947f38088 100644
--- a/core/fpdfapi/page/cpdf_colorspace.h
+++ b/core/fpdfapi/page/cpdf_colorspace.h
@@ -126,8 +126,7 @@ class CPDF_ColorSpace : public Retainable, public Observable {
                                   int pixels,
                                   int image_width,
                                   int image_height,
-                                  bool bTransMask) const;
-  virtual void EnableStdConversion(bool bEnabled);
+                                  bool is_transparency_mask) const;
   virtual bool IsNormal() const;
 
   // Returns `this` as a CPDF_PatternCS* if `this` is a pattern.
@@ -149,7 +148,6 @@ class CPDF_ColorSpace : public Retainable, public Observable {
   // components count.
   void SetComponentsForStockCS(uint32_t nComponents);
 
-  bool IsStdConversionEnabled() const { return std_conversion_ != 0; }
   bool HasSameArray(const CPDF_Object* pObj) const { return array_ == pObj; }
 
  private:
@@ -160,7 +158,6 @@ class CPDF_ColorSpace : public Retainable, public Observable {
       ByteStringView bsFamilyName);
 
   const Family family_;
-  uint32_t std_conversion_ = 0;
   uint32_t components_ = 0;
   RetainPtr<const CPDF_Array> array_;
 };
diff --git a/core/fpdfapi/page/cpdf_colorspace_unittest.cpp b/core/fpdfapi/page/cpdf_colorspace_unittest.cpp
index 63b81544b..fe298bf58 100644
--- a/core/fpdfapi/page/cpdf_colorspace_unittest.cpp
+++ b/core/fpdfapi/page/cpdf_colorspace_unittest.cpp
@@ -22,8 +22,8 @@ TEST(CPDFCalGrayTest, TranslateImageLine) {
   const uint8_t kSrc[12] = {255, 0, 0, 0, 255, 0, 0, 0, 255, 128, 128, 128};
   uint8_t dst[12];
   std::ranges::fill(dst, 0xbd);
-  // `bTransMask` only applies to CYMK colorspaces.
-  pCal->TranslateImageLine(dst, kSrc, 4, 4, 1, /*bTransMask=*/false);
+  // Transparency masks are only used with CMYK colorspaces, not CalGray.
+  pCal->TranslateImageLine(dst, kSrc, 4, 4, 1, /*is_transparency_mask=*/false);
   EXPECT_THAT(dst, ElementsAre(255, 255, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0));
 }
 
@@ -34,7 +34,7 @@ TEST(CPDFCalRGBTest, TranslateImageLine) {
   const uint8_t kSrc[12] = {255, 0, 0, 0, 255, 0, 0, 0, 255, 128, 128, 128};
   uint8_t dst[12];
   std::ranges::fill(dst, 0xbd);
-  // `bTransMask` only applies to CYMK colorspaces.
-  pCal->TranslateImageLine(dst, kSrc, 4, 4, 1, /*bTransMask=*/false);
+  // Transparency masks are only used with CMYK colorspaces, not CalRGB.
+  pCal->TranslateImageLine(dst, kSrc, 4, 4, 1, /*is_transparency_mask=*/false);
   EXPECT_THAT(dst, ElementsAre(0, 0, 255, 0, 255, 0, 255, 0, 0, 128, 128, 128));
 }
diff --git a/core/fpdfapi/page/cpdf_decodedimagestore.cpp b/core/fpdfapi/page/cpdf_decodedimagestore.cpp
index d93affc5f..22416f408 100644
--- a/core/fpdfapi/page/cpdf_decodedimagestore.cpp
+++ b/core/fpdfapi/page/cpdf_decodedimagestore.cpp
@@ -46,16 +46,15 @@ struct CPDF_DecodedImageStore::Entry {
   const size_t bytes;
 };
 
-CPDF_DecodedImageStore::Key::Key(RetainPtr<const CPDF_Stream> stream,
-                                 const CPDF_Document* document,
-                                 RetainPtr<const CPDF_Dictionary> page_resources,
-                                 bool std_cs,
-                                 CPDF_ColorSpace::Family family,
-                                 bool load_mask)
+CPDF_DecodedImageStore::Key::Key(
+    RetainPtr<const CPDF_Stream> stream,
+    const CPDF_Document* document,
+    RetainPtr<const CPDF_Dictionary> page_resources,
+    CPDF_ColorSpace::Family family,
+    bool load_mask)
     : stream_(std::move(stream)),
       page_resources_(std::move(page_resources)),
       document_(reinterpret_cast<uintptr_t>(document)),
-      std_cs_(std_cs),
       family_(family),
       load_mask_(load_mask) {}
 
@@ -67,10 +66,9 @@ CPDF_DecodedImageStore::Key& CPDF_DecodedImageStore::Key::operator=(
 CPDF_DecodedImageStore::Key::~Key() = default;
 
 bool CPDF_DecodedImageStore::Key::operator<(const Key& that) const {
-  return std::tie(stream_, page_resources_, document_, std_cs_, family_,
-                  load_mask_) < std::tie(that.stream_, that.page_resources_,
-                                         that.document_, that.std_cs_,
-                                         that.family_, that.load_mask_);
+  return std::tie(stream_, page_resources_, document_, family_, load_mask_) <
+         std::tie(that.stream_, that.page_resources_, that.document_,
+                  that.family_, that.load_mask_);
 }
 
 CPDF_DecodedImageStore::Decoded::Decoded() = default;
@@ -100,7 +98,6 @@ CPDF_DecodedImageStore* CPDF_DecodedImageStore::Get() {
 std::optional<CPDF_DecodedImageStore::Key> CPDF_DecodedImageStore::KeyFor(
     const CPDF_Image& image,
     const CPDF_Dictionary* page_resources,
-    bool std_cs,
     CPDF_ColorSpace::Family family,
     bool load_mask) {
   CPDF_DecodedImageStore* store = Get();
@@ -114,7 +111,7 @@ std::optional<CPDF_DecodedImageStore::Key> CPDF_DecodedImageStore::KeyFor(
     return std::nullopt;
   }
   return Key(std::move(stream), image.GetDocument(),
-             pdfium::WrapRetain(page_resources), std_cs, family, load_mask);
+             pdfium::WrapRetain(page_resources), family, load_mask);
 }
 
 CPDF_DecodedImageStore::CPDF_DecodedImageStore() = default;
diff --git a/core/fpdfapi/page/cpdf_decodedimagestore.h b/core/fpdfapi/page/cpdf_decodedimagestore.h
index a61f1b44c..469959ac7 100644
--- a/core/fpdfapi/page/cpdf_decodedimagestore.h
+++ b/core/fpdfapi/page/cpdf_decodedimagestore.h
@@ -38,7 +38,6 @@ class CPDF_DecodedImageStore {
     Key(RetainPtr<const CPDF_Stream> stream,
         const CPDF_Document* document,
         RetainPtr<const CPDF_Dictionary> page_resources,
-        bool std_cs,
         CPDF_ColorSpace::Family family,
         bool load_mask);
     Key(const Key& that);
@@ -56,7 +55,6 @@ class CPDF_DecodedImageStore {
     RetainPtr<const CPDF_Dictionary> page_resources_;
     // The document's address: only compared, never used.
     uintptr_t document_;
-    bool std_cs_;
     CPDF_ColorSpace::Family family_;
     bool load_mask_;
   };
@@ -80,7 +78,6 @@ class CPDF_DecodedImageStore {
   // keep such an image.
   static std::optional<Key> KeyFor(const CPDF_Image& image,
                                    const CPDF_Dictionary* page_resources,
-                                   bool std_cs,
                                    CPDF_ColorSpace::Family family,
                                    bool load_mask);
 
diff --git a/core/fpdfapi/page/cpdf_devicecs.cpp b/core/fpdfapi/page/cpdf_devicecs.cpp
index 822c52198..03a1bbaef 100644
--- a/core/fpdfapi/page/cpdf_devicecs.cpp
+++ b/core/fpdfapi/page/cpdf_devicecs.cpp
@@ -62,13 +62,6 @@ std::optional<FX_RGB_STRUCT<float>> CPDF_DeviceCS::GetRGB(
     case Family::kDeviceCMYK: {
       const auto& cmyk =
           fxcrt::reinterpret_span<const FX_CMYK_STRUCT<float>>(pBuf).front();
-      if (IsStdConversionEnabled()) {
-        return FX_RGB_STRUCT<float>{
-            1.0f - std::min(1.0f, cmyk.cyan + cmyk.key),
-            1.0f - std::min(1.0f, cmyk.magenta + cmyk.key),
-            1.0f - std::min(1.0f, cmyk.yellow + cmyk.key),
-        };
-      }
       return AdobeCmykToStandardRgbF(
           NormalizeChannel(cmyk.cyan), NormalizeChannel(cmyk.magenta),
           NormalizeChannel(cmyk.yellow), NormalizeChannel(cmyk.key));
@@ -83,11 +76,12 @@ void CPDF_DeviceCS::TranslateImageLine(pdfium::span<uint8_t> dest_span,
                                        int pixels,
                                        int image_width,
                                        int image_height,
-                                       bool bTransMask) const {
+                                       bool is_transparency_mask) const {
   auto rgb_out = fxcrt::reinterpret_span<FX_RGB_STRUCT<uint8_t>>(dest_span);
   switch (GetFamily()) {
     case Family::kDeviceGray:
-      CHECK(!bTransMask);  // bTransMask only allowed for CMYK colorspaces.
+      // Transparency masks are only used with CMYK colorspaces, not DeviceGray.
+      CHECK(!is_transparency_mask);
       // Compiler can't conclude src/dest don't overlap, avoid interleaved
       // loads and stores by not using an auto& reference here.
       for (const auto pix : src_span.first(static_cast<size_t>(pixels))) {
@@ -98,13 +92,14 @@ void CPDF_DeviceCS::TranslateImageLine(pdfium::span<uint8_t> dest_span,
       }
       break;
     case Family::kDeviceRGB:
-      CHECK(!bTransMask);  // bTransMask only allowed for CMYK colorspaces.
+      // Transparency masks are only used with CMYK colorspaces, not DeviceRGB.
+      CHECK(!is_transparency_mask);
       fxcodec::ReverseRGB(dest_span, src_span, pixels);
       break;
     case Family::kDeviceCMYK: {
       auto cmyk_in =
           fxcrt::reinterpret_span<const FX_CMYK_STRUCT<uint8_t>>(src_span);
-      if (bTransMask) {
+      if (is_transparency_mask) {
         // Compiler can't conclude src/dest don't overlap, avoid interleaved
         // loads and stores by not using an auto& reference here.
         for (const auto cmyk : cmyk_in.first(static_cast<size_t>(pixels))) {
@@ -116,18 +111,6 @@ void CPDF_DeviceCS::TranslateImageLine(pdfium::span<uint8_t> dest_span,
         }
         break;
       }
-      if (IsStdConversionEnabled()) {
-        // Compiler can't conclude src/dest don't overlap, avoid interleaved
-        // loads and stores by not using am auto& reference here,
-        for (const auto cmyk : cmyk_in.first(static_cast<size_t>(pixels))) {
-          const uint8_t k = cmyk.key;
-          rgb_out.front().blue = 255 - std::min(255, cmyk.cyan + k);
-          rgb_out.front().green = 255 - std::min(255, cmyk.magenta + k);
-          rgb_out.front().red = 255 - std::min(255, cmyk.yellow + k);
-          rgb_out = rgb_out.subspan<1u>();
-        }
-        break;
-      }
       for (const auto& cmyk : cmyk_in.first(static_cast<size_t>(pixels))) {
         // TODO(tsepez): maybe this is a FX_BGR_STRUCT in reality?
         FX_RGB_STRUCT<uint8_t> rgb = AdobeCmykToStandardRgb(
diff --git a/core/fpdfapi/page/cpdf_devicecs.h b/core/fpdfapi/page/cpdf_devicecs.h
index 5fff876a7..8fb476932 100644
--- a/core/fpdfapi/page/cpdf_devicecs.h
+++ b/core/fpdfapi/page/cpdf_devicecs.h
@@ -25,7 +25,7 @@ class CPDF_DeviceCS final : public CPDF_ColorSpace {
                           int pixels,
                           int image_width,
                           int image_height,
-                          bool bTransMask) const override;
+                          bool is_transparency_mask) const override;
   uint32_t v_Load(CPDF_Document* doc,
                   const CPDF_Array* pArray,
                   std::set<const CPDF_Object*>* pVisited) override;
diff --git a/core/fpdfapi/page/cpdf_dib.cpp b/core/fpdfapi/page/cpdf_dib.cpp
index 3c7e87466..d872ad66f 100644
--- a/core/fpdfapi/page/cpdf_dib.cpp
+++ b/core/fpdfapi/page/cpdf_dib.cpp
@@ -162,14 +162,6 @@ bool CPDF_DIB::Load() {
   return ContinueInternal();
 }
 
-bool CPDF_DIB::ContinueToLoadMask() {
-  if (color_space_ && std_cs_) {
-    color_space_->EnableStdConversion(true);
-  }
-
-  return ContinueInternal();
-}
-
 bool CPDF_DIB::ContinueInternal() {
   if (image_mask_) {
     SetMaskProperties();
@@ -213,11 +205,9 @@ CPDF_DIB::LoadState CPDF_DIB::StartLoadDIBBase(
     bool bHasMask,
     const CPDF_Dictionary* pFormResources,
     const CPDF_Dictionary* pPageResources,
-    bool bStdCS,
     CPDF_ColorSpace::Family GroupFamily,
     bool bLoadMask,
     const CFX_Size& max_size_required) {
-  std_cs_ = bStdCS;
   has_mask_ = bHasMask;
   group_family_ = GroupFamily;
   load_mask_ = bLoadMask;
@@ -240,7 +230,7 @@ CPDF_DIB::LoadState CPDF_DIB::StartLoadDIBBase(
     return LoadState::kFail;
   }
 
-  if (!ContinueToLoadMask()) {
+  if (!ContinueInternal()) {
     return LoadState::kFail;
   }
 
@@ -252,9 +242,6 @@ CPDF_DIB::LoadState CPDF_DIB::StartLoadDIBBase(
 
   DCHECK_EQ(iCreatedDecoder, LoadState::kSuccess);
   DCHECK_EQ(iLoadedMask, LoadState::kSuccess);
-  if (color_space_ && std_cs_) {
-    color_space_->EnableStdConversion(false);
-  }
   return LoadState::kSuccess;
 }
 
@@ -326,13 +313,6 @@ CPDF_DIB::LoadState CPDF_DIB::ContinueLoadDIBBase(PauseIndicatorIface* pPause) {
       status_ = LoadState::kContinue;
     }
   }
-  if (iContinueStatus == LoadState::kContinue) {
-    return LoadState::kContinue;
-  }
-
-  if (color_space_ && std_cs_) {
-    color_space_->EnableStdConversion(false);
-  }
   return iContinueStatus;
 }
 
@@ -387,6 +367,11 @@ bool CPDF_DIB::LoadColorInfo(const CPDF_Dictionary* pFormResources,
   // decoded.
   components_ = color_space_->ComponentCount();
   family_ = color_space_->GetFamily();
+  if (family_ == CPDF_ColorSpace::Family::kPattern) {
+    // Per ISO 32000-1:2008, section 8.9.5.1, table 89, the ColorSpace entry of
+    // an image dictionary can be any type of color space except Pattern.
+    return false;
+  }
   if (family_ == CPDF_ColorSpace::Family::kICCBased && pCSObj->IsName()) {
     ByteString cs = pCSObj->GetString();
     if (cs == "DeviceGray") {
@@ -877,8 +862,7 @@ CPDF_DIB::LoadState CPDF_DIB::StartLoadMask() {
   }
 
   RetainPtr<const CPDF_Array> pMatte = mask->GetDict()->GetArrayFor("Matte");
-  if (pMatte && color_space_ && family_ != CPDF_ColorSpace::Family::kPattern &&
-      pMatte->size() == components_ &&
+  if (pMatte && color_space_ && pMatte->size() == components_ &&
       color_space_->ComponentCount() <= components_) {
     std::vector<float> colors =
         ReadArrayElementsToVector(pMatte.Get(), components_);
@@ -901,10 +885,6 @@ CPDF_DIB::LoadState CPDF_DIB::ContinueLoadMaskDIB(PauseIndicatorIface* pPause) {
     return LoadState::kContinue;
   }
 
-  if (color_space_ && std_cs_) {
-    color_space_->EnableStdConversion(false);
-  }
-
   if (ret == LoadState::kFail) {
     mask_.Reset();
     return LoadState::kFail;
@@ -944,7 +924,7 @@ CPDF_DIB::LoadState CPDF_DIB::StartLoadMaskDIB(
     RetainPtr<const CPDF_Stream> mask_stream) {
   mask_ = pdfium::MakeRetain<CPDF_DIB>(document_, std::move(mask_stream));
   LoadState ret =
-      mask_->StartLoadDIBBase(false, nullptr, nullptr, true,
+      mask_->StartLoadDIBBase(false, nullptr, nullptr,
                               CPDF_ColorSpace::Family::kUnknown, false, {0, 0});
   if (ret == LoadState::kContinue) {
     if (status_ == LoadState::kFail) {
@@ -959,7 +939,7 @@ CPDF_DIB::LoadState CPDF_DIB::StartLoadMaskDIB(
 }
 
 void CPDF_DIB::LoadPalette() {
-  if (!color_space_ || family_ == CPDF_ColorSpace::Family::kPattern) {
+  if (!color_space_) {
     return;
   }
 
@@ -1108,7 +1088,7 @@ void CPDF_DIB::TranslateScanline24bpp(
       rgb.red = (1.0f - color_values[0]) * k;
       rgb.green = (1.0f - color_values[1]) * k;
       rgb.blue = (1.0f - color_values[2]) * k;
-    } else if (family_ != CPDF_ColorSpace::Family::kPattern) {
+    } else {
       rgb = color_space_->GetRGBOrZerosOnError(color_values);
     }
     const float R = std::clamp(rgb.red, 0.0f, 1.0f);
diff --git a/core/fpdfapi/page/cpdf_dib.h b/core/fpdfapi/page/cpdf_dib.h
index 39b47bcd9..bb33475d6 100644
--- a/core/fpdfapi/page/cpdf_dib.h
+++ b/core/fpdfapi/page/cpdf_dib.h
@@ -75,7 +75,6 @@ class CPDF_DIB final : public CFX_DIBBase {
   LoadState StartLoadDIBBase(bool bHasMask,
                              const CPDF_Dictionary* pFormResources,
                              const CPDF_Dictionary* pPageResources,
-                             bool bStdCS,
                              CPDF_ColorSpace::Family GroupFamily,
                              bool bLoadMask,
                              const CFX_Size& max_size_required);
@@ -100,7 +99,6 @@ class CPDF_DIB final : public CFX_DIBBase {
   bool ContinueInternal();
   LoadState StartLoadMask();
   LoadState StartLoadMaskDIB(RetainPtr<const CPDF_Stream> mask_stream);
-  bool ContinueToLoadMask();
   LoadState ContinueLoadMaskDIB(PauseIndicatorIface* pPause);
   bool LoadColorInfo(const CPDF_Dictionary* pFormResources,
                      const CPDF_Dictionary* pPageResources);
@@ -154,7 +152,6 @@ class CPDF_DIB final : public CFX_DIBBase {
   bool do_bpc_check_ = true;
   bool color_key_ = false;
   bool has_mask_ = false;
-  bool std_cs_ = false;
   std::vector<DIB_COMP_DATA> comp_data_;
   mutable DataVector<uint8_t> line_buf_;
   mutable DataVector<uint8_t> mask_buf_;
diff --git a/core/fpdfapi/page/cpdf_image.cpp b/core/fpdfapi/page/cpdf_image.cpp
index 4aef6e7dc..74bbc1320 100644
--- a/core/fpdfapi/page/cpdf_image.cpp
+++ b/core/fpdfapi/page/cpdf_image.cpp
@@ -569,14 +569,13 @@ RetainPtr<CFX_DIBBase> CPDF_Image::DetachMask() {
 
 bool CPDF_Image::StartLoadDIBBase(const CPDF_Dictionary* pFormResource,
                                   const CPDF_Dictionary* pPageResource,
-                                  bool bStdCS,
                                   CPDF_ColorSpace::Family GroupFamily,
                                   bool bLoadMask,
                                   const CFX_Size& max_size_required) {
   RetainPtr<CPDF_DIB> source = CreateNewDIB();
   CPDF_DIB::LoadState ret =
-      source->StartLoadDIBBase(true, pFormResource, pPageResource, bStdCS,
-                               GroupFamily, bLoadMask, max_size_required);
+      source->StartLoadDIBBase(true, pFormResource, pPageResource, GroupFamily,
+                               bLoadMask, max_size_required);
   if (ret == CPDF_DIB::LoadState::kFail) {
     dibbase_.Reset();
     return false;
diff --git a/core/fpdfapi/page/cpdf_image.h b/core/fpdfapi/page/cpdf_image.h
index a0ef86cfa..7e65562ac 100644
--- a/core/fpdfapi/page/cpdf_image.h
+++ b/core/fpdfapi/page/cpdf_image.h
@@ -92,7 +92,6 @@ class CPDF_Image final : public Retainable {
   // Returns whether to Continue() or not.
   bool StartLoadDIBBase(const CPDF_Dictionary* pFormResource,
                         const CPDF_Dictionary* pPageResource,
-                        bool bStdCS,
                         CPDF_ColorSpace::Family GroupFamily,
                         bool bLoadMask,
                         const CFX_Size& max_size_required);
diff --git a/core/fpdfapi/page/cpdf_imageloader.cpp b/core/fpdfapi/page/cpdf_imageloader.cpp
index f49ed99f6..067c00a4d 100644
--- a/core/fpdfapi/page/cpdf_imageloader.cpp
+++ b/core/fpdfapi/page/cpdf_imageloader.cpp
@@ -24,7 +24,6 @@ bool CPDF_ImageLoader::Start(const CPDF_ImageObject* pImage,
                              CPDF_PageImageCache* pPageImageCache,
                              const CPDF_Dictionary* pFormResource,
                              const CPDF_Dictionary* pPageResource,
-                             bool bStdCS,
                              CPDF_ColorSpace::Family eFamily,
                              bool bLoadMask,
                              const CFX_Size& max_size_required) {
@@ -38,12 +37,11 @@ bool CPDF_ImageLoader::Start(const CPDF_ImageObject* pImage,
   bool should_continue;
   if (cache_) {
     should_continue = cache_->StartGetCachedBitmap(
-        image_object_->GetImage(), pFormResource, pPageResource, bStdCS,
-        eFamily, bLoadMask, max_size_required);
+        image_object_->GetImage(), pFormResource, pPageResource, eFamily,
+        bLoadMask, max_size_required);
   } else {
     should_continue = image_object_->GetImage()->StartLoadDIBBase(
-        pFormResource, pPageResource, bStdCS, eFamily, bLoadMask,
-        max_size_required);
+        pFormResource, pPageResource, eFamily, bLoadMask, max_size_required);
   }
   if (!should_continue) {
     Finish();
diff --git a/core/fpdfapi/page/cpdf_imageloader.h b/core/fpdfapi/page/cpdf_imageloader.h
index 50eb0cefd..bd49c3a42 100644
--- a/core/fpdfapi/page/cpdf_imageloader.h
+++ b/core/fpdfapi/page/cpdf_imageloader.h
@@ -27,7 +27,6 @@ class CPDF_ImageLoader {
              CPDF_PageImageCache* pPageImageCache,
              const CPDF_Dictionary* pFormResource,
              const CPDF_Dictionary* pPageResource,
-             bool bStdCS,
              CPDF_ColorSpace::Family eFamily,
              bool bLoadMask,
              const CFX_Size& max_size_required);
diff --git a/core/fpdfapi/page/cpdf_pageimagecache.cpp b/core/fpdfapi/page/cpdf_pageimagecache.cpp
index 90c984398..ca97a1ad0 100644
--- a/core/fpdfapi/page/cpdf_pageimagecache.cpp
+++ b/core/fpdfapi/page/cpdf_pageimagecache.cpp
@@ -175,7 +175,6 @@ bool CPDF_PageImageCache::StartGetCachedBitmap(
     RetainPtr<CPDF_Image> pImage,
     const CPDF_Dictionary* pFormResources,
     const CPDF_Dictionary* pPageResources,
-    bool bStdCS,
     CPDF_ColorSpace::Family eFamily,
     bool bLoadMask,
     const CFX_Size& max_size_required) {
@@ -194,7 +193,7 @@ bool CPDF_PageImageCache::StartGetCachedBitmap(
     cur_image_cache_entry_ = std::make_unique<Entry>(std::move(pImage));
   }
   CPDF_DIB::LoadState ret = cur_image_cache_entry_->StartGetCachedBitmap(
-      this, pFormResources, pPageResources, bStdCS, eFamily, bLoadMask,
+      this, pFormResources, pPageResources, eFamily, bLoadMask,
       max_size_required);
   if (ret == CPDF_DIB::LoadState::kContinue) {
     return true;
@@ -279,7 +278,6 @@ CPDF_DIB::LoadState CPDF_PageImageCache::Entry::StartGetCachedBitmap(
     CPDF_PageImageCache* pPageImageCache,
     const CPDF_Dictionary* pFormResources,
     const CPDF_Dictionary* pPageResources,
-    bool bStdCS,
     CPDF_ColorSpace::Family eFamily,
     bool bLoadMask,
     const CFX_Size& max_size_required) {
@@ -291,8 +289,8 @@ CPDF_DIB::LoadState CPDF_PageImageCache::Entry::StartGetCachedBitmap(
 
   // EmbedPDF(decoded-image-store): consulted only where the cache would
   // decode; a stored decode leaves the entry as a new decode would.
-  store_key_ = CPDF_DecodedImageStore::KeyFor(*image_, pPageResources, bStdCS,
-                                              eFamily, bLoadMask);
+  store_key_ = CPDF_DecodedImageStore::KeyFor(*image_, pPageResources, eFamily,
+                                              bLoadMask);
   if (store_key_) {
     // The levels StartLoadDIBBase() would compute, from the same dictionary.
     RetainPtr<const CPDF_Dictionary> dict = image_->GetStream()->GetDict();
@@ -320,7 +318,7 @@ CPDF_DIB::LoadState CPDF_PageImageCache::Entry::StartGetCachedBitmap(
 
   cur_bitmap_ = image_->CreateNewDIB();
   CPDF_DIB::LoadState ret = cur_bitmap_.AsRaw<CPDF_DIB>()->StartLoadDIBBase(
-      true, pFormResources, pPageResources, bStdCS, eFamily, bLoadMask,
+      true, pFormResources, pPageResources, eFamily, bLoadMask,
       max_size_required);
   cached_set_max_size_required_ =
       (max_size_required.width != 0 && max_size_required.height != 0);
diff --git a/core/fpdfapi/page/cpdf_pageimagecache.h b/core/fpdfapi/page/cpdf_pageimagecache.h
index 44ded0bce..9da8a0fc8 100644
--- a/core/fpdfapi/page/cpdf_pageimagecache.h
+++ b/core/fpdfapi/page/cpdf_pageimagecache.h
@@ -43,7 +43,6 @@ class CPDF_PageImageCache {
   bool StartGetCachedBitmap(RetainPtr<CPDF_Image> pImage,
                             const CPDF_Dictionary* pFormResources,
                             const CPDF_Dictionary* pPageResources,
-                            bool bStdCS,
                             CPDF_ColorSpace::Family eFamily,
                             bool bLoadMask,
                             const CFX_Size& max_size_required);
@@ -71,7 +70,6 @@ class CPDF_PageImageCache {
         CPDF_PageImageCache* pPageImageCache,
         const CPDF_Dictionary* pFormResources,
         const CPDF_Dictionary* pPageResources,
-        bool bStdCS,
         CPDF_ColorSpace::Family eFamily,
         bool bLoadMask,
         const CFX_Size& max_size_required);
diff --git a/core/fpdfapi/page/cpdf_pageimagecache_unittest.cpp b/core/fpdfapi/page/cpdf_pageimagecache_unittest.cpp
index 860c93b39..f5be95de1 100644
--- a/core/fpdfapi/page/cpdf_pageimagecache_unittest.cpp
+++ b/core/fpdfapi/page/cpdf_pageimagecache_unittest.cpp
@@ -107,7 +107,7 @@ TEST_F(CPDFPageImageCacheTest, RenderBug1924) {
 
     // Render with small scale.
     bool should_continue = page_image_cache->StartGetCachedBitmap(
-        image->GetImage(), nullptr, page->GetMutablePageResources(), true,
+        image->GetImage(), nullptr, page->GetMutablePageResources(),
         CPDF_ColorSpace::Family::kICCBased, false, {50, 50});
     while (should_continue) {
       should_continue = page_image_cache->Continue(nullptr);
@@ -117,7 +117,7 @@ TEST_F(CPDFPageImageCacheTest, RenderBug1924) {
 
     // And render with large scale.
     should_continue = page_image_cache->StartGetCachedBitmap(
-        image->GetImage(), nullptr, page->GetMutablePageResources(), true,
+        image->GetImage(), nullptr, page->GetMutablePageResources(),
         CPDF_ColorSpace::Family::kICCBased, false, {100, 100});
     while (should_continue) {
       should_continue = page_image_cache->Continue(nullptr);
@@ -251,7 +251,7 @@ TEST_F(CPDFPageImageCacheTest, RenderReducedDctThenFullSize) {
 
   // Render with small scale: 400/50 -> 1/8, so a 50x50 bitmap.
   bool should_continue = page_image_cache->StartGetCachedBitmap(
-      image->GetImage(), nullptr, page->GetMutablePageResources(), true,
+      image->GetImage(), nullptr, page->GetMutablePageResources(),
       CPDF_ColorSpace::Family::kUnknown, false, {50, 50});
   while (should_continue) {
     should_continue = page_image_cache->Continue(nullptr);
@@ -264,7 +264,7 @@ TEST_F(CPDFPageImageCacheTest, RenderReducedDctThenFullSize) {
   // Render with large scale: 400/100 -> 1/4, so a 100x100 bitmap. The cached
   // 50x50 bitmap is too small, so this forces a higher-resolution re-decode.
   should_continue = page_image_cache->StartGetCachedBitmap(
-      image->GetImage(), nullptr, page->GetMutablePageResources(), true,
+      image->GetImage(), nullptr, page->GetMutablePageResources(),
       CPDF_ColorSpace::Family::kUnknown, false, {100, 100});
   while (should_continue) {
     should_continue = page_image_cache->Continue(nullptr);
@@ -312,7 +312,7 @@ TEST_F(CPDFPageImageCacheTest, RenderReducedDctWithSMask) {
 
   // Draw small so the 400x400 base is decoded at reduced resolution.
   bool should_continue = page_image_cache->StartGetCachedBitmap(
-      image->GetImage(), nullptr, page->GetMutablePageResources(), true,
+      image->GetImage(), nullptr, page->GetMutablePageResources(),
       CPDF_ColorSpace::Family::kUnknown, /*bLoadMask=*/true, {50, 50});
   while (should_continue) {
     should_continue = page_image_cache->Continue(nullptr);
@@ -370,7 +370,7 @@ TEST_F(CPDFPageImageCacheTest, NonMcuAlignedDctIsNotReduced) {
   // Draw small: an MCU-aligned image would be reduced here, but this one must
   // not be, so the decoded bitmap stays at the full 408x408.
   bool should_continue = page_image_cache->StartGetCachedBitmap(
-      image->GetImage(), nullptr, page->GetMutablePageResources(), true,
+      image->GetImage(), nullptr, page->GetMutablePageResources(),
       CPDF_ColorSpace::Family::kUnknown, false, {50, 50});
   while (should_continue) {
     should_continue = page_image_cache->Continue(nullptr);
diff --git a/core/fpdfapi/render/cpdf_imagerenderer.cpp b/core/fpdfapi/render/cpdf_imagerenderer.cpp
index 5d1e4fa8f..aa291f04b 100644
--- a/core/fpdfapi/render/cpdf_imagerenderer.cpp
+++ b/core/fpdfapi/render/cpdf_imagerenderer.cpp
@@ -73,8 +73,7 @@ bool CPDF_ImageRenderer::StartLoadDIBBase() {
   if (!loader_->Start(
           image_object_, render_status_->GetContext()->GetPageCache(),
           render_status_->GetFormResource(), render_status_->GetPageResource(),
-          std_cs_, render_status_->GetGroupFamily(),
-          render_status_->GetLoadMask(),
+          render_status_->GetGroupFamily(), render_status_->GetLoadMask(),
           {render_status_->GetRenderDevice()->GetWidth(),
            render_status_->GetRenderDevice()->GetHeight()})) {
     return false;
@@ -186,10 +185,8 @@ bool CPDF_ImageRenderer::StartRenderDIBBase() {
 }
 
 bool CPDF_ImageRenderer::Start(CPDF_ImageObject* pImageObject,
-                               const CFX_Matrix& mtObj2Device,
-                               bool bStdCS) {
+                               const CFX_Matrix& mtObj2Device) {
   DCHECK(pImageObject);
-  std_cs_ = bStdCS;
   image_object_ = pImageObject;
   blend_type_ = BlendMode::kNormal;
   obj_to_device_ = mtObj2Device;
@@ -209,14 +206,12 @@ bool CPDF_ImageRenderer::Start(CPDF_ImageObject* pImageObject,
 bool CPDF_ImageRenderer::Start(RetainPtr<CFX_DIBBase> pDIBBase,
                                FX_ARGB bitmap_argb,
                                const CFX_Matrix& mtImage2Device,
-                               const FXDIB_ResampleOptions& options,
-                               bool bStdCS) {
+                               const FXDIB_ResampleOptions& options) {
   dibbase_ = std::move(pDIBBase);
   fill_argb_ = bitmap_argb;
   alpha_ = 1.0f;
   image_matrix_ = mtImage2Device;
   resample_options_ = options;
-  std_cs_ = bStdCS;
   blend_type_ = BlendMode::kNormal;
   return StartDIBBase();
 }
@@ -281,12 +276,11 @@ RetainPtr<const CFX_DIBitmap> CPDF_ImageRenderer::CalculateDrawImage(
     CPDF_RenderStatus mask_status(render_status_->GetContext(),
                                   mask_device.get());
     mask_status.SetDropObjects(render_status_->GetDropObjects());
-    mask_status.SetStdCS(true);
     mask_status.Initialize(nullptr, nullptr);
 
     CPDF_ImageRenderer mask_renderer(&mask_status);
     if (mask_renderer.Start(std::move(pDIBBase), 0xffffffff, mtNewMatrix,
-                            resample_options_, true)) {
+                            resample_options_)) {
       mask_renderer.Continue(nullptr);
     }
     if (loader_->MatteColor() != 0xffffffff) {
@@ -349,7 +343,6 @@ bool CPDF_ImageRenderer::DrawPatternImage() {
                                   bitmap_device.get());
   bitmap_status.SetOptions(GetRenderOptions());
   bitmap_status.SetDropObjects(render_status_->GetDropObjects());
-  bitmap_status.SetStdCS(true);
   bitmap_status.Initialize(nullptr, nullptr);
 
   CFX_Matrix pattern_matrix = obj_to_device_;
@@ -404,10 +397,9 @@ bool CPDF_ImageRenderer::DrawMaskedImage() {
   CPDF_RenderStatus bitmap_status(render_status_->GetContext(),
                                   bitmap_device.get());
   bitmap_status.SetDropObjects(render_status_->GetDropObjects());
-  bitmap_status.SetStdCS(true);
   bitmap_status.Initialize(nullptr, nullptr);
   CPDF_ImageRenderer bitmap_renderer(&bitmap_status);
-  if (bitmap_renderer.Start(dibbase_, 0, new_matrix, resample_options_, true)) {
+  if (bitmap_renderer.Start(dibbase_, 0, new_matrix, resample_options_)) {
     bitmap_renderer.Continue(nullptr);
   }
   RetainPtr<const CFX_DIBitmap> mask_bitmap = CalculateDrawImage(
diff --git a/core/fpdfapi/render/cpdf_imagerenderer.h b/core/fpdfapi/render/cpdf_imagerenderer.h
index 610f20f68..d3784aa9c 100644
--- a/core/fpdfapi/render/cpdf_imagerenderer.h
+++ b/core/fpdfapi/render/cpdf_imagerenderer.h
@@ -36,15 +36,12 @@ class CPDF_ImageRenderer {
   explicit CPDF_ImageRenderer(CPDF_RenderStatus* pStatus);
   ~CPDF_ImageRenderer();
 
-  bool Start(CPDF_ImageObject* pImageObject,
-             const CFX_Matrix& mtObj2Device,
-             bool bStdCS);
+  bool Start(CPDF_ImageObject* pImageObject, const CFX_Matrix& mtObj2Device);
 
   bool Start(RetainPtr<CFX_DIBBase> pDIBBase,
              FX_ARGB bitmap_argb,
              const CFX_Matrix& mtImage2Device,
-             const FXDIB_ResampleOptions& options,
-             bool bStdCS);
+             const FXDIB_ResampleOptions& options);
 
   bool Continue(PauseIndicatorIface* pPause);
   bool GetResult() const { return result_; }
@@ -106,7 +103,6 @@ class CPDF_ImageRenderer {
   FX_ARGB fill_argb_ = 0;
   FXDIB_ResampleOptions resample_options_;
   bool pattern_color_ = false;
-  bool std_cs_ = false;
   bool result_ = true;
 };
 
diff --git a/core/fpdfapi/render/cpdf_renderstatus.cpp b/core/fpdfapi/render/cpdf_renderstatus.cpp
index a5ef266a8..dd40df698 100644
--- a/core/fpdfapi/render/cpdf_renderstatus.cpp
+++ b/core/fpdfapi/render/cpdf_renderstatus.cpp
@@ -309,8 +309,7 @@ bool CPDF_RenderStatus::ContinueSingleObject(CPDF_PageObject* pObj,
   }
 
   image_renderer_ = std::make_unique<CPDF_ImageRenderer>(this);
-  if (!image_renderer_->Start(pObj->AsImage(), mtObj2Device,
-                              /*bStdCS=*/false)) {
+  if (!image_renderer_->Start(pObj->AsImage(), mtObj2Device)) {
     if (!image_renderer_->GetResult()) {
       DrawObjWithBackground(pObj, mtObj2Device);
     }
@@ -771,7 +770,6 @@ bool CPDF_RenderStatus::ProcessTransparency(CPDF_PageObject* pPageObj,
   CPDF_RenderStatus bitmap_render(context_, bitmap_device.get());
   bitmap_render.SetOptions(options_);
   bitmap_render.SetStopObject(stop_obj_);
-  bitmap_render.SetStdCS(true);
   bitmap_render.SetDropObjects(drop_objects_);
   bitmap_render.SetFormResource(std::move(pFormResource));
   bitmap_render.SetInGroup(transparency.IsGroup());
@@ -1107,7 +1105,7 @@ bool CPDF_RenderStatus::ProcessType3Text(CPDF_TextObject* textobj,
         CFX_Matrix image_matrix = pType3Char->matrix() * matrix;
         CPDF_ImageRenderer renderer(this);
         if (renderer.Start(pType3Char->GetBitmap(), fill_argb, image_matrix,
-                           FXDIB_ResampleOptions(), false)) {
+                           FXDIB_ResampleOptions())) {
           renderer.Continue(nullptr);
         }
         if (!renderer.GetResult()) {
@@ -1350,7 +1348,7 @@ void CPDF_RenderStatus::ProcessPathPattern(
 bool CPDF_RenderStatus::ProcessImage(CPDF_ImageObject* pImageObj,
                                      const CFX_Matrix& mtObj2Device) {
   CPDF_ImageRenderer render(this);
-  if (render.Start(pImageObj, mtObj2Device, std_cs_)) {
+  if (render.Start(pImageObj, mtObj2Device)) {
     render.Continue(nullptr);
   }
   return render.GetResult();
@@ -1544,7 +1542,6 @@ RetainPtr<CFX_DIBitmap> CPDF_RenderStatus::LoadSMask(
   status.SetOptions(options);
   status.SetGroupFamily(nCSFamily);
   status.SetLoadMask(bLuminosity);
-  status.SetStdCS(true);
   status.SetFormResource(std::move(pFormResource));
   status.SetDropObjects(drop_objects_);
   status.Initialize(nullptr, nullptr);
diff --git a/core/fpdfapi/render/cpdf_renderstatus.h b/core/fpdfapi/render/cpdf_renderstatus.h
index b002aa312..9050264fa 100644
--- a/core/fpdfapi/render/cpdf_renderstatus.h
+++ b/core/fpdfapi/render/cpdf_renderstatus.h
@@ -59,7 +59,6 @@ class CPDF_RenderStatus {
   void SetFillColor(FX_ARGB color) { t3_fill_color_ = color; }
   void SetDropObjects(bool bDropObjects) { drop_objects_ = bDropObjects; }
   void SetLoadMask(bool bLoadMask) { load_mask_ = bLoadMask; }
-  void SetStdCS(bool bStdCS) { std_cs_ = bStdCS; }
   void SetGroupFamily(CPDF_ColorSpace::Family family) {
     group_family_ = family;
   }
@@ -210,7 +209,6 @@ class CPDF_RenderStatus {
   bool print_ = false;
 #endif
   bool drop_objects_ = false;
-  bool std_cs_ = false;
   bool load_mask_ = false;
   bool in_group_ = false;
   CPDF_ColorSpace::Family group_family_ = CPDF_ColorSpace::Family::kUnknown;
diff --git a/core/fpdfapi/render/fpdf_render_pattern_embeddertest.cpp b/core/fpdfapi/render/fpdf_render_pattern_embeddertest.cpp
index 184f1f474..bc13fef9b 100644
--- a/core/fpdfapi/render/fpdf_render_pattern_embeddertest.cpp
+++ b/core/fpdfapi/render/fpdf_render_pattern_embeddertest.cpp
@@ -58,3 +58,12 @@ TEST_F(FPDFRenderPatternEmbedderTest, ZeroTilingPatternStep509964646) {
   ScopedFPDFBitmap bitmap = RenderLoadedPage(page.get());
   ASSERT_TRUE(bitmap);
 }
+
+TEST_F(FPDFRenderPatternEmbedderTest, ImagePatternColorSpace) {
+  // Rendering an image with a Pattern color space should not crash.
+  ASSERT_TRUE(OpenDocument("image_pattern_colorspace.pdf"));
+  ScopedPage page = LoadScopedPage(0);
+  ASSERT_TRUE(page);
+  ScopedFPDFBitmap bitmap = RenderLoadedPage(page.get());
+  ASSERT_TRUE(bitmap);
+}
diff --git a/docs/embedpdf/syncs/2026-11-04-2b52a82ab.md b/docs/embedpdf/syncs/2026-11-04-2b52a82ab.md
new file mode 100644
index 000000000..fb7fd263b
--- /dev/null
+++ b/docs/embedpdf/syncs/2026-11-04-2b52a82ab.md
@@ -0,0 +1,106 @@
+# Sync 2026-11-04: upstream 5f092b529..2b52a82ab (14 commits)
+
+## Summary
+
+Upstream from 2026-11-01 to 2026-11-02, merged into `27c505705`.
+
+Upstream removed the "standard" CMYK conversion for images (images with soft masks or non-normal
+blend modes now convert CMYK like everything else), rejects Pattern color spaces for images (a
+crash on malformed files), and rolled Skia, V8, ICU, zlib and test tools. No conflicts; our decoded
+image store and image redactor drop the removed `bStdCS` argument.
+
+## Likely security fixes
+
+None.
+
+## Conflicts (0 files, 0 blocks)
+
+None.
+
+## Write audit (0 lines)
+
+None.
+
+## Upstream changes outside the conflicts
+
+- **No more "standard" CMYK conversion (`2b52a82ab`).** Images drawn with a soft mask or a
+  non-normal blend mode converted DeviceCMYK with `1 - min(1, C + K)`; they now use the same CMYK
+  conversion as everything else, which upstream says matches other renderers (its corpus test
+  `bug_557320961` changed). Such images render a little differently; engine render expectations
+  with CMYK images under soft masks or blend modes may move when the engine adopts this runtime.
+  The `bStdCS` / `std_cs_` plumbing is gone, so:
+  - our decoded image store (`cpdf_decodedimagestore.*`, decoded-image-store) no longer keys on
+    `std_cs`; the conversion no longer depends on it;
+  - `cpdf_pageimagecache.cpp` and the image redactor (`cpdf_image_redactor.cpp`) call the loaders
+    without it.
+- **Pattern color spaces rejected for images (`bbb9926d4`):** ISO 32000-1 table 89 forbids them; an
+  8 bpc image with one reached a `NOTREACHED()` in `CPDF_PatternCS::GetRGB()`, so a malformed file
+  could crash rendering. The image now fails to load instead.
+- **Renames (`7e01bafbd`):** `bTransMask` to `is_transparency_mask`; nothing of ours used the name.
+- Merged into files we change: `cpdf_colorspace`, `cpdf_dib`, `cpdf_image`, `cpdf_imageloader`,
+  `cpdf_pageimagecache`, `cpdf_renderstatus`, `fpdf_editimg.cpp`; all of upstream's hunks present.
+
+## Upstream appearance generator
+
+None.
+
+## Globals
+
+No new globals by the heuristic. `check-globals.py` on the darwin-arm64 release build: ok (263 shared
+writable, 25 thread-local).
+
+## Build and patches
+
+- `DEPS` changed in 11 commits: Skia (`04d4d5c8a`, 139 commits), V8 (`9185ccc21`, not in our
+  builds), ICU (`f7878a86a`), zlib (`69856420f`), fast_float (`b75764a1d`), googletest
+  (`38ee50754`), llvm-libc (`55a435dce`), `tools/win` (`42ca51961`), Catapult and Jinja2, and the
+  reproxy config removed (`bc5a4257b`). Synced with `gclient sync --no-history --shallow`.
+- All of `patches/embedpdf-runtime/` apply: every target's patches dry-run against clean sources,
+  and darwin-arm64 and wasm32 build.
+
+## API diff
+
+None. The darwin-arm64 exports match the public headers, as in S15.
+
+## Tests
+
+- [x] fork unit + embedder tests (darwin-arm64): 1320 unit tests pass. Embedder: 1784 tests,
+  9 skipped, 12 failing: exactly S15's list, every one "Pixels do not match" against a Mac PNG
+  golden. Linux runs in the PR's CI.
+  The 12, as the baseline for the next sync:
+  - `EPDFMeasureEmbedderTest.CaptionAppearanceGolden`
+  - `FPDFEditEmbedderTest.SetTextRenderMode`
+  - `FPDFProgressiveRenderEmbedderTest.RenderAnnotWithPause`
+  - `FPDFProgressiveRenderEmbedderTest.RenderFormsWithPause`
+  - `FPDFProgressiveRenderEmbedderTest.RenderHighlightWithColorScheme`
+  - `FPDFProgressiveRenderEmbedderTest.RenderHighlightWithColorSchemeAndConvertFillToStroke`
+  - `FPDFProgressiveRenderEmbedderTest.RenderStampWithColorScheme`
+  - `FPDFProgressiveRenderEmbedderTest.RenderTextWithColorScheme`
+  - `FPDFProgressiveRenderEmbedderTest.RenderWithPause`
+  - `FPDFProgressiveRenderEmbedderTest.RenderWithoutPause`
+  - `FPDFViewEmbedderTest.RenderBug664284WithNoNativeText`
+  - `FPDFViewEmbedderTest.RenderHelloWorldWithFlags`
+- [x] layer mode: exit 0; 213 layer-only failures, all expected; 185 crashes as in S15; 507 writers
+  (main now runs in-memory and linearized tests through layers, `e90678020` and #111). One warning:
+  `EPDFSlicedLoadEmbedderTest.SlicesKeepToTheirBudget` failed under load and passed alone, a timing
+  test, as in S11. (A Mac recording drops the Linux-only `TransFormWithClipAndSaveWithLocale`; its
+  line stays.)
+- [x] tag check (`--base 2b52a82ab`): 1012 blocks, 0 untagged.
+- [x] C API check: ok, 590 functions in 24 headers.
+- [x] globals check: ok.
+- [x] wasm build: builds locally.
+- [ ] ThreadSanitizer soak: in the PR's CI.
+- [ ] engine tests and engine-conformance with the local runtime: not run for this sync.
+- changed expectations, each with its reason:
+  - Layer-mode writers: added `EPDFAnnotEmbedderTest.AcrobatCommentWrittenBackReadsTheSame` (1
+    object), which came with #110 (`605f21fa1`) unrecorded; it writes a markup comment back, and
+    without it the release workflow's layer-mode gate fails.
+  - Layer-mode writer counts, informational: `EPDFPpoEmbedderTest.AddsToAFormAndRenamesAFontItUses`
+    1 to 20, `RenamesAFontWithOtherWidths` 2 to 20, `RenamesTheFontOfAnAppearanceWithAComment` 2 to
+    20, `SharesAFontDefinedTheSameWay` 1 to 19 (their destination is a `NewTestDocument()`, a layer
+    since `e90678020`, so the whole import counts); `RichTextSkipsDocumentSubsetWithoutCmap` 6 to 7,
+    `NumberFormatsRoundTripAndAbsentVersusEmpty` 1 to 4.
+
+## Ledger changes proposed
+
+None.
diff --git a/fpdfsdk/fpdf_editimg.cpp b/fpdfsdk/fpdf_editimg.cpp
index 8bc82c20a..797df8511 100644
--- a/fpdfsdk/fpdf_editimg.cpp
+++ b/fpdfsdk/fpdf_editimg.cpp
@@ -362,8 +362,7 @@ FPDFImageObj_GetRenderedBitmap(FPDF_DOCUMENT document,
   }
 
   // Do the actual rendering.
-  bool should_continue =
-      renderer.Start(image, image_render_matrix, /*bStdCS=*/false);
+  bool should_continue = renderer.Start(image, image_render_matrix);
   while (should_continue) {
     should_continue = renderer.Continue(/*pPause=*/nullptr);
   }
@@ -530,7 +529,7 @@ FPDFImageObj_GetImageMetadata(FPDF_PAGEOBJECT image_object,
 
   RetainPtr<CPDF_DIB> pSource = pImg->CreateNewDIB();
   CPDF_DIB::LoadState ret = pSource->StartLoadDIBBase(
-      false, nullptr, pPage->GetPageResources().Get(), false,
+      false, nullptr, pPage->GetPageResources().Get(),
       CPDF_ColorSpace::Family::kUnknown, false, {0, 0});
   if (ret == CPDF_DIB::LoadState::kFail) {
     return true;
diff --git a/fpdfsdk/fpdf_thumbnail.cpp b/fpdfsdk/fpdf_thumbnail.cpp
index 18fe04909..97ec3e7c1 100644
--- a/fpdfsdk/fpdf_thumbnail.cpp
+++ b/fpdfsdk/fpdf_thumbnail.cpp
@@ -81,7 +81,7 @@ FPDFPage_GetThumbnailAsBitmap(FPDF_PAGE page) {
   auto dib_source = pdfium::MakeRetain<CPDF_DIB>(pdf_page->GetDocument(),
                                                  std::move(thumb_stream));
   const CPDF_DIB::LoadState start_status = dib_source->StartLoadDIBBase(
-      false, nullptr, pdf_page->GetPageResources().Get(), false,
+      false, nullptr, pdf_page->GetPageResources().Get(),
       CPDF_ColorSpace::Family::kUnknown, false, {0, 0});
   if (start_status == CPDF_DIB::LoadState::kFail) {
     return nullptr;
diff --git a/testing/embedpdf_layer_mode_writers.txt b/testing/embedpdf_layer_mode_writers.txt
index d8fc78617..2a455f68c 100644
--- a/testing/embedpdf_layer_mode_writers.txt
+++ b/testing/embedpdf_layer_mode_writers.txt
@@ -49,6 +49,7 @@ EPDFActionEmbedderTest.NodeFilePathAndNamePayloadsFromSyntheticDicts 2
 EPDFActionEmbedderTest.OpenActionDestinationForms 3
 EPDFActionEmbedderTest.ResetFormThreeStates 1
 EPDFActionEmbedderTest.SetNextChainsActions 3
+EPDFAnnotEmbedderTest.AcrobatCommentWrittenBackReadsTheSame 1
 EPDFAnnotEmbedderTest.AnEmptyDashPatternIsASolidLine 15
 EPDFAnnotEmbedderTest.AnnotFontMapStagesEveryNamedFont 16
 EPDFAnnotEmbedderTest.ApplyPageRedactionsCountsRemovedAnnotations 6
@@ -149,7 +150,7 @@ EPDFAnnotEmbedderTest.RichTextPicksTheDocumentSubsetThatCoversTheText 16
 EPDFAnnotEmbedderTest.RichTextPreviewAndPrintLastResortWaits 25
 EPDFAnnotEmbedderTest.RichTextResolvesDocumentProgramWhenUnregistered 24
 EPDFAnnotEmbedderTest.RichTextRtlRunCarriesActualTextAndExtracts 14
-EPDFAnnotEmbedderTest.RichTextSkipsDocumentSubsetWithoutCmap 6
+EPDFAnnotEmbedderTest.RichTextSkipsDocumentSubsetWithoutCmap 7
 EPDFAnnotEmbedderTest.RichTextWriterFailureLeavesDocumentUntouched 18
 EPDFAnnotEmbedderTest.RotatedCaretAppearanceCarriesTransform 3
 EPDFAnnotEmbedderTest.SetDefaultAppearanceKeepsFontAtAutoSize 5
@@ -262,7 +263,7 @@ EPDFMeasureEmbedderTest.LayerReadsPromoteNothingAndPageWritesOnlyPage 5
 EPDFMeasureEmbedderTest.LineAndShapeCaptionEntriesStaySeparate 5
 EPDFMeasureEmbedderTest.LineAppearanceLeadersInlineGapAndStableBounds 7
 EPDFMeasureEmbedderTest.MissingOrMalformedConversionNeverBecomesOne 4
-EPDFMeasureEmbedderTest.NumberFormatsRoundTripAndAbsentVersusEmpty 1
+EPDFMeasureEmbedderTest.NumberFormatsRoundTripAndAbsentVersusEmpty 4
 EPDFMeasureEmbedderTest.RegisteredCaptionFontsStayOutOfCatalogAndEphemeralWrites 11
 EPDFMeasureEmbedderTest.ShapeCaptionBoundsShrinkWhenMovedInward 6
 EPDFMeasureEmbedderTest.ShapeCaptionCenterRoundTripsAndOnlyChangesVisualBounds 7
@@ -298,14 +299,14 @@ EPDFPieceInfoEmbedderTest.CatalogGranularClearPreservesOtherData 4
 EPDFPieceInfoEmbedderTest.CatalogTypedValuesSaveReloadAndLayerRead 4
 EPDFPieceInfoEmbedderTest.GranularClearPreservesOtherData 3
 EPDFPieceInfoEmbedderTest.TypedValuesSaveReloadAndImport 3
-EPDFPpoEmbedderTest.AddsToAFormAndRenamesAFontItUses 1
+EPDFPpoEmbedderTest.AddsToAFormAndRenamesAFontItUses 20
 EPDFPpoEmbedderTest.BringsOnlyWhatIsAboveThePagesWidgets 12
 EPDFPpoEmbedderTest.BringsTheFieldsOfEveryPage 18
 EPDFPpoEmbedderTest.CopiesOutOfALayerAsTheLayerReadsIt 14
 EPDFPpoEmbedderTest.PointsCopiedParentsAtTheCopies 15
-EPDFPpoEmbedderTest.RenamesAFontWithOtherWidths 2
-EPDFPpoEmbedderTest.RenamesTheFontOfAnAppearanceWithAComment 2
-EPDFPpoEmbedderTest.SharesAFontDefinedTheSameWay 1
+EPDFPpoEmbedderTest.RenamesAFontWithOtherWidths 20
+EPDFPpoEmbedderTest.RenamesTheFontOfAnAppearanceWithAComment 20
+EPDFPpoEmbedderTest.SharesAFontDefinedTheSameWay 19
 EPDFRedactEmbedderTest.DirectReplacementTextIsRemovedFromSiblingObjects 3
 EPDFRedactEmbedderTest.InheritedPropertiesLeaveNoUnusedOriginalOnPage 5
 EPDFRedactEmbedderTest.NestedFormsUseTheRenderersTransformOrder 7
diff --git a/testing/resources/image_pattern_colorspace.in b/testing/resources/image_pattern_colorspace.in
new file mode 100644
index 000000000..8234b2a88
--- /dev/null
+++ b/testing/resources/image_pattern_colorspace.in
@@ -0,0 +1,51 @@
+{{header}}
+{{object 1 0}} <<
+  /Type /Catalog
+  /Pages 2 0 R
+>>
+endobj
+{{object 2 0}} <<
+  /Type /Pages
+  /Count 1
+  /Kids [3 0 R]
+>>
+endobj
+{{object 3 0}} <<
+  /Type /Page
+  /Parent 2 0 R
+  /MediaBox [0 0 100 100]
+  /Contents 4 0 R
+  /Resources <<
+    /XObject <<
+      /Im0 5 0 R
+    >>
+  >>
+>>
+endobj
+{{object 4 0}} <<
+  {{streamlen}}
+>>
+stream
+q
+100 0 0 100 0 0 cm
+/Im0 Do
+Q
+endstream
+endobj
+{{object 5 0}} <<
+  /Type /XObject
+  /Subtype /Image
+  /Width 1
+  /Height 1
+  /BitsPerComponent 8
+  /ColorSpace [/Pattern /DeviceRGB]
+  {{streamlen}}
+>>
+stream
+abcd
+endstream
+endobj
+{{xref}}
+{{trailer}}
+{{startxref}}
+%%EOF
diff --git a/testing/resources/image_pattern_colorspace.pdf b/testing/resources/image_pattern_colorspace.pdf
new file mode 100644
index 000000000..3be90cccb
Binary files /dev/null and b/testing/resources/image_pattern_colorspace.pdf differ
diff --git a/testing/resources/pixel/bug_557320961_expected.pdf.0.png b/testing/resources/pixel/bug_557320961_expected.pdf.0.png
index 397ef476c..8850e8975 100644
Binary files a/testing/resources/pixel/bug_557320961_expected.pdf.0.png and b/testing/resources/pixel/bug_557320961_expected.pdf.0.png differ