[dvipdfmx] bug with inclusion of a PNG

[Shunsaku Hirata]

> It seems to me that a PDF file with a CalRGB entry would have to contain an ICC Profile in order to be PDF/X compliant. Would anyone be able to chime on that?

The CalRGB color space is a calibrated color space that does not use
an ICC profile.
In these color spaces, colors are specified in a way that is
independent of the characteristics of any particular output device.
The CalRGB color space is characterized by just a few parameters while
ICC profile is more complicated.

I think PDF/X-3 and above allow both CalRGB and ICCBased (color space
with ICC profile).
If you want PDF/X-1a compliance you need to convert them to CMYK.

Thanks,
Shunsaku Hirata

2021年1月15日(金) 13:57 Paulo Ney de Souza <pauloney at gmail.com>:
>
> Indeed this PNG has an sRGB chunk and it exhibits the behavior we have described -- when placed against a background of the same color it displays a difference in tonality. I have previously said that XeTeX and LibreOffice are doing the same thing, but that is not exactly correct, I'll fix that below.
>
> Behavior 1 - The included PNG shows a different tonality against a background of the same color, when saved to PDF - on SOME (but not ALL) output devices.
> Program: XeTeX
>
> Behavior 2 -  The included PNG shows a different tonality against a background of the same color, when saved to PDF - on ALL output devices.
> Program: LibreOffice
>
> Behavior 3 -  The included PNG does NOT show a different tonality against a background of the same color, when saved to PDF - on ANY device.
> Programs: PDFTeX, LuaTeX, Adobe InDesign, Chrome, MS Publisher, MS Word, Adobe Illustrator and Photoshop.
>
> It seems to me that a PDF file with a CalRGB entry would have to contain an ICC Profile in order to be PDF/X compliant. Would anyone be able to chime on that?
>
> Paulo Ney
>
>
> On Thu, Jan 14, 2021 at 7:20 AM Shunsaku Hirata <shunsaku.hirata74 at gmail.com> wrote:
>>
>> OK, I will send another one where an sRGB chunk was added to
>> A.png by TweakPNG program.
>>
>> Thanks,
>> Shunsaku Hirata
>>
>> 2021年1月14日(木) 22:48 Philip Taylor <P.Taylor at hellenic-institute.uk>:
>> >
>> > Shunsaku Hirata wrote:
>> >
>> > Do you have a PNG that any of these tools report an sRGB chunk?
>> >
>> > I have created a PNG file that has a sRGB chunk. (Same image as
>> > A.png but just sRGB chunk added)
>> >
>> >
>> > Confirmed, but I have an odd feeling that some other chunks seems to have disappeared ...
>> >
>> >
>> >
>> >