Image Color Fidelity in Monthly Contest

[Sean]

Javio,

I just posted an entry in the July monthly contest (Thanks for organizing this!) and noticed that the color fidelity of my included image doesn't seem very good. I'm using Firefox 4 which uses managed color, and when I open the same image directly from my hard drive in Firefox it looks fine. Also, my linked image on my website looks fine in Firefox. However, the thumbnail and expanded image on the PI page has very muted colors. There is an embedded sRGB profile in the JPG that I uploaded.

Any ideas?

Thanks,

Sean

[Juan Conejero]

Hi Sean,

Yes, I know what happens The image on your website, namely:

http://www.drakevisual.com/astro-photos/astro-photos/10378927?pictureId=10378927&asGalleryImage=true

has the Adobe RGB (1998) ICC profile embedded. To generate the contest thumbnail image, you have assigned the sRGB IEC61966-2.1 profile (for example, using the AssignICCProfile tool in PixInsight). However, that is not correct. By doing that, you are saying that current pixel values in your image are referred to the sRGB color space, which is not true.

What you have to do is converting your image to the sRGB IEC61966-2.1 color space. To do this, use the ICCProfileTransformation tool in PixInsight. In this way you'll have pixels referred to the sRGB space and the corresponding profile correctly embedded in your image. Give it a try and you'll see how your image is nicely displayed by Firefox 4.

[Sean]

Juan,

Thanks for your detective work - I went back and fixed the embedded images on the PI site - looks much better. I'll also fix the one on the my own website in a few minutes.

This color management stuff is so confusing!

Sean