WSUPP-42: Adding default colour profile conversion for CMYK mode JPEG images.

Dockerfile

@@ -6,23 +6,24 @@ ENV TMPDIR=$APPETISER_DIR/tmp
 ENV OUTPUT_DIR=$APPETISER_DIR/out/
 
 RUN apt-get update -y && apt-get install -y \
-  cmake=3.31.6-2 \
-  netpbm=2:11.10.02-1 \
-  ghostscript=10.05.1~dfsg-1 \
-  libgs10=10.05.1~dfsg-1 \
-  libgs10-common=10.05.1~dfsg-1 \
-  libffi-dev=3.4.8-2 \
-  libjpeg-turbo-progs=1:2.1.5-4 \
-  libtiff5-dev=4.7.0-3 \
-  libjpeg62-turbo-dev=1:2.1.5-4 \
-  zlib1g-dev=1:1.3.dfsg+really1.3.1-1+b1 \
-  liblcms2-dev=2.16-2 \
-  libwebp-dev=1.5.0-0.1 \
-  tcl8.6-dev=8.6.16+dfsg-1 \
-  tk8.6-dev=8.6.16-1 \
-  python3-tk=3.13.5-1\
-  libharfbuzz-dev=10.2.0-1+b1 \
-  libfribidi-dev=1.0.16-1
+  cmake \
+  netpbm \
+  ghostscript \
+  libgs10 \
+  libgs10-common \
+  libffi-dev \
+  libjpeg-turbo-progs \
+  libtiff5-dev \
+  libjpeg62-turbo-dev \
+  zlib1g-dev \
+  liblcms2-dev \
+  libwebp-dev \
+  tcl8.6-dev \
+  tk8.6-dev \
+  python3-tk \
+  libharfbuzz-dev \
+  libfribidi-dev \
+  && rm -rf /var/lib/apt/lists/*
 
 COPY ./appetiser/ $APPETISER_DIR/appetiser/
 COPY ./pyproject.toml $APPETISER_DIR

appetiser/convert/image.py

@@ -167,25 +167,33 @@ def _image_has_transparency(img: PILImage) -> bool:
     return False
 
 
+CMYK_COLOUR_PROFILE = str(
+    Path(__file__).resolve().parent / "color_profiles/GRACoL2006_Coated1v2.icc"
+)
+
+
 def _convert_img_colour_profile(img: PILImage, img_filename: str = "") -> PILImage:
     """If the image has ICC profile information, apply a transformation to this
     image from that ICC colour profile to the sRGB colour profile.
     """
+    source_profile = None
     img_colour_profile_bytes = img.info.get("icc_profile")
     if img_colour_profile_bytes:
         logger.debug(f"Extracting embedded colour profile: {img_filename}")
-        img_colour_profile = ImageCms.ImageCmsProfile(
-            io.BytesIO(img_colour_profile_bytes)
-        )
-        img_colour_profile_name = ImageCms.getProfileName(img_colour_profile)
-        logger.debug(f"Using icc colour profile: {img_colour_profile_name}")
+        source_profile = ImageCms.ImageCmsProfile(io.BytesIO(img_colour_profile_bytes))
+    elif img.mode == "CMYK":
+        logger.debug(f"Loading default CMYK colour profile: {CMYK_COLOUR_PROFILE}")
+        source_profile = ImageCms.ImageCmsProfile(CMYK_COLOUR_PROFILE)
+    if source_profile:
+        source_profile_name = ImageCms.getProfileName(source_profile)
+        logger.debug(f"Using icc colour profile: {source_profile_name}")
         sRGB_profile = ImageCms.createProfile("sRGB")
         logger.debug(
-            f"Converting colour profile: {img_colour_profile_name} to {sRGB_profile.profile_description}, {img_filename}"
+            f"Converting colour profile: {source_profile_name} to {sRGB_profile.profile_description}, {img_filename}"
         )
         output_mode = "RGBA" if _image_has_transparency(img) else "RGB"
         img = ImageCms.profileToProfile(
-            img, img_colour_profile, sRGB_profile, outputMode=output_mode
+            img, source_profile, sRGB_profile, outputMode=output_mode
         )
 
     return img
@@ -207,6 +215,7 @@ def _convert_img_to_tiff(filepath: Path) -> tuple[Path, dict]:
         )
         logger.debug("%s: saving as raw to %s", filepath, tiff_filepath)
         img.save(tiff_filepath, compression=None)
+        img_info["mode"] = img.mode
     return tiff_filepath, img_info
 
 

appetiser/convert/operations.py

@@ -47,12 +47,7 @@ def convert_image_to_jp2(
     else:
         image_mode = image_info.get("mode")
         logger.debug(
-            "Converting with colour profile: {prepared_source=}, {image_mode=}"
-        )
-        logger.debug(
-            "%s: Being used for conversion to JPEG2000, with colour mode: %s",
-            prepared_source,
-            image_mode,
+            f"Converting with colour profile: {prepared_source=}, {image_mode=}"
         )
         kdu_compress(
             config=config,
@@ -240,7 +235,7 @@ def create_thumbnails(
             width=calc_thumb_info.width,
             height=calc_thumb_info.height,
             dest_path=calc_thumb_info.path,
-            config=config
+            config=config,
         )
         thumbnail_info.append(
             ThumbInfo(

tests/test_convert_image_cmyk.py

@@ -0,0 +1,17 @@
+from .utils import (
+    convert_test_runner,
+)
+
+
+def test_convert_cmyk_image(appetiser_service, fixtures_dir, output_dir):
+    convert_test_runner(
+        appetiser_service=appetiser_service,
+        output_dir=output_dir,
+        fixtures_dir=fixtures_dir,
+        img_path="10_02_18.jpg",
+        expected_jp2_name="10_02_18.jp2",
+        optimisation="kdu_med",
+        operation="image-only",
+        thumb_iiif_sizes=None,
+        expected_thumb_sizes=None,
+    )