CP-2474 Add more standard color spaces Status Letter Ballot Date of Last Update 2025/06/17 Person Assigned David Clunie Submitter Name Bart Diricx Submission Date 2024/11/03 Correction Number CP-2474 Log Summary: Add more standard color spaces Name of Standard PS3.3, PS3.18 Rationale for Correction: There is value in using standard color spaces with a wider gamut than others currently defined, such as Display-P3. See also http://en.wikipedia.org/wiki/DCI-P3 for a discussion between the relationship of Display-P3 and DCI-P3 . Correction Wording: <informaltable rules="all" frame="box"> <tr> <td> <para><emphasis role="italic">Amend DICOM PS3.3 and PS3.18 to add new reference as follows (changes to existing text are bold and <emphasis role="bold"><emphasis role="underline" >underlined</emphasis></emphasis> for additions and <emphasis role="bold" ><emphasis role="strikethrough">struckthrough</emphasis></emphasis> for removals):</emphasis></para> </td> </tr> </informaltable> <section label="2" status="1" xml:id="chapter_2"> <title>Normative References IEC 61966-2.1 IEC 1999 Ed 1.0 Multimedia systems and equipment - <foreignphrase xml:lang="en-GB">colour</foreignphrase> measurement and management - Part 2.1: <foreignphrase xml:lang="en-GB">colour</foreignphrase> management - Default RGB <foreignphrase xml:lang="en-GB">colour</foreignphrase> space - sRGB ISO 22028-2 ISO 2013 Photography and graphic technology - Extended colour encodings for digital image storage, manipulation and interchange - Part 2: Reference output medium metric RGB colour image encoding (ROMM RGB) Adobe RGB Adobe Systems Incorporated 1998 2005-05 Adobe RGB (1998) Color Image Encoding Display-P3 Apple, Inc <emphasis role="bold"><emphasis role="underline">Display P3 Color Encoding</emphasis></emphasis> SMPTE RP 431-2:2011 Society of Motion Picture and Television Engineers (SMPTE) 2011 <emphasis role="bold"><emphasis role="underline">D-Cinema Quality — Reference Projector and Environment</emphasis></emphasis> DCI DCSS Digital Cinema Initiatives, LLC. (DCI) May 29, 2024 <emphasis role="bold"><emphasis role="underline">Digital Cinema System Specification</emphasis></emphasis> Amend DICOM PS3.3 as follows (changes to existing text are bold and underlined for additions and struckthrough for removals):
ICC Profile Module
ICC Profile Module Attributes
Attribute Name Tag Type Attribute Description
ICC Profile (0028,2000) 1 An ICC Profile encoding the transformation of device-dependent color stored pixel values into PCS-Values.
Color Space (0028,2002) 3 A label that identifies the well-known color space of the image. Shall be consistent with any ICC Profile (0028,2000) that is also present. See .
ICC Profile Module Attribute Descriptions
ICC Profile ...
Color Space The Color Space Attribute provides a label that identifies the color space by name, when the ICC Profile (0028, 2000) (if present) describes a well-known color space. Defined Terms: SRGB ICC Profile (0028,2000) defines sRGB color space ADOBERGB ICC Profile (0028,2000) defines Adobe RGB color space ROMMRGB ICC Profile (0028,2000) defines ROMM RGB color space DISPLAYP3 ICC Profile (0028,2000) defines Display-P3 color space The Display-P3 color space is similar to but not the same as DCI-P3 color space (defined in ). Display-P3 uses the sRGB transfer function whereas DCI-P3 uses a gamma of 2.6 for the transfer function, and a different white point (D65 vs D63). The reason for using Display-P3 in DICOM rather than DCI-P3 is because web browser technology has native support for it, whereas DCI-P3 was designed for digital cinema applications .
Amend DICOM PS3.18 as follows (changes to existing text are bold and underlined for additions and struckthrough for removals):
Query Parameters for Rendered Resources ...
Retrieve Rendered Query Parameters
Key Values Target Resource Category Section
...
iccprofile "no", "yes", "srgb", "adobergb" or, "rommrgb", or "displayp3" Image (single or multi-frame) or Video
ICC Profile The "iccprofile" parameter specifies the color characteristics of, and inclusion of an ICC Profile in, the rendered images. It has the following syntax: %s"iccprofile=" 1#( %s"no" / %s"yes" / %s"srgb" / %s"adobergb" / %s"rommrgb" / %s"displayp3" ) Where "no" indicates that no ICC profile shall be present in the rendered image in the response. "yes" indicates that an ICC profile shall be present in the rendered image in the response, describing its color characteristics, if the Media Type supports embedded ICC Profiles. "srgb" indicates that an sRGB ICC profile shall be present in the image, if the Media Type supports embedded ICC Profiles, and that the pixels of the rendered image in the response shall be transformed from their original color space and be encoded in the sRGB color space [IEC 61966-2.1]. "adobergb" indicates that an Adobe RGB ICC profile shall be present in the image, if the Media Type supports embedded ICC Profiles, and that the pixels of the rendered image in the response shall be transformed from their original color space and be encoded in the Adobe RGB color space [Adobe RGB]. "rommrgb" indicates that a ROMM RGB ICC profile shall be present in the image, if the Media Type supports embedded ICC Profiles, and that the pixels of the rendered image in the response shall be transformed from their original color space and encoded in the ROMM RGB color space [ISO 22028-2]. "displayp3" indicates that a Display-P3 ICC profile shall be present in the image, if the Media Type supports embedded ICC Profiles, and that the pixels of the rendered image in the response shall be transformed from their original color space and encoded in the Display-P3 color space When this parameter is not present: an ICC profile may or may not be present in the image in the response; the color characteristics of the image in the response may or may not be consistent with any DICOM ICC Profile (0028,2000) Attribute in the metadata. The ICC Profile in the image in the response shall be: the ICC profile of the color space specified explicitly by the parameter, otherwise, the ICC profile encoded in the source DICOM ICC Profile (0028,2000) Attribute, if any, appropriate to the selected frame, otherwise, the ICC profile, if any, embedded in the stored compressed representation of the selected frame, otherwise, at the discretion of the origin server, the ICC profile of a well-known color space listed in that is appropriate to the type and source of the image. If the Media Type does not support embedded ICC Profiles: a 400 Bad Request error shall be returned if the parameter value is other than "no" This parameter allows ICC profile information to be present in the image in the response so that the user agent can make use of it for local color management (e.g., an ICC profile capable browser can apply the profile when displaying the rendered image in the response). This parameter provides a limited mechanism for requesting that the origin server perform some color management. It provides the names of well-known color spaces for the rendered image in the response. It does not provide a mechanism to supply an arbitrary ICC profile, such as the calibration profile of a display, so it does not absolve the user agent from the need to handle its own color calibration and color management. ICC profiles can theoretically be large relative to the compressed pixel data of a single frame, so the user agent may specify a parameter value of "no", retrieve the DICOM ICC Profile (0028,2000) Attribute value(s) that apply to multiple frames from the metadata, and combine these itself. ICC profiles are embedded in rendered images of Media Type image/jpeg as one or more chunks in APP2 marker segments with an identifier of "ICC_PROFILE", as defined in Annex B of . ICC profiles are embedded in rendered images of Media Type image/jp2 either as JP2 Restricted or JPX Full profiles according to and , respectively; rendered images in the response are not subject to the prohibition against inclusion of a JP2 box in JPEG 2000 compressed data streams in DICOM images. ICC profiles are embedded in rendered images of Media Type image/png in an iCCP chunk, as defined in .