Color management observations

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Winfried
Posts: 239
Joined: June 18th, 2010, 4:27 pm
What is the make/model of your primary camera?: Pentax K1

Color management observations

Post by Winfried »

I made two observations:
- the tumbnails are not color managed (normally no problem)
- the Exif-flag regarding the the color space is not honoured, i.e. if I set my camera to sRGB and shot JPGs PWP8 does not recognsises this.
Same with Adobe RGB. JPG from camera normally don't contain an icc-profile, but just set the exif-flag.
Winfried
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migrated to Windows 10 in Nov. 2019
PWP Pro 64
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jsachs
Posts: 4203
Joined: January 22nd, 2009, 11:03 pm

Re: Color management observations

Post by jsachs »

There is code in PWP 8 to infer the color space from the EXIF data, although the standard is vague with regards to AdobeRGB. Can you email me a sample JPEG file so I can check the EXIF tags?
Jonathan Sachs
Digital Light & Color
jsachs
Posts: 4203
Joined: January 22nd, 2009, 11:03 pm

Re: Color management observations

Post by jsachs »

Apparently, the Microsoft GDI+ code PWP8 uses to read JPEG files inserts an "opRGB" profile in the image. The LeadTools JPEG reader used by PWP7 did not do this. opRGB is a so-called "optional" profile which has the same properties as AdobeRGB (the official version of which is copyrighted).

If there is no profile, PWP 8 does look at the EXIF data and infers sRGB or AdobeRGB and inserts these profiles into the file automatically. This is what happens when reading TIFF files generated by a RAW converter, for example. Unfortunately since opRGB does not exactly match AdobeRGB byte-for-byte, PWP8 performs an unnecessary conversion from one to the other when reading jpeg files.
Jonathan Sachs
Digital Light & Color
jsachs
Posts: 4203
Joined: January 22nd, 2009, 11:03 pm

Re: Color management observations

Post by jsachs »

I fixed this problem for the next release by detecting opRGB and, if found, replacing it with AdobeRGB.
Jonathan Sachs
Digital Light & Color
jsachs
Posts: 4203
Joined: January 22nd, 2009, 11:03 pm

Re: Color management observations

Post by jsachs »

Thumbnails are now color managed for the next (20-Apr) release.
Jonathan Sachs
Digital Light & Color
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