On 03/10/2010 02:37 AM, Sven Neumann wrote:
> Some file formats, such as PNG for example, allow to tag the file to be
> in a particular well-known color space. The color profile is not
> embedded then, it is assumed to be well-defined. Instead of distributing
> the profile with the image file, there is just a flag saying "this data
> should be interpreted as sRGB".

Ah, so the color problems I am having with images created by Gimp are 
due to the PNG files being 'tagged' as sRGB. The color profile isn't 
embedded to the image, it's just specified and, since it's a well known 
color profile, any program that attempts to display the image will do so 
as though the PNG had an embedded sRGB profile. Thanks for pointing that 

To summarize:
Tagging is great because it specifies a color profile without increasing 
the image file size. Assuming that the destination system applies the 
correct profile.

Embedding is great because you have greater flexibility for an endless 
variety of custom color profiles.

The end result of the two is the same though: the image will be color 


As for gballard's recommendation for not including color profiles in web 
images: He's only saying that because his ultimate goal is color 
consistency across all platforms/browsers.

I, as a professional web designer, think he's right when it comes to 
page element images that are intended to match colors defined in HTML or 
CSS. Otherwise all of the Safari users that visit your site are going to 
doubt your design capabilities. For photographs I think it's fine to 
include color profiles. Browsers that don't color manage are going to 
show you the same limited gamut either way, but browsers that DO color 
manage will display an enhanced image with a wider gamut of colors. 
Progressive enhancement.

You do have to also keep in mind that profiled/tagged sRGB and 
un-profiled/un-tagged RGB images will display differently in color 
managed browsers/environments. The assumption that Gimp currently makes 
(for historical reasons, explained by Sven previously) about 'assigning 
sRGB color profile' being the same as 'having no color profile' is 

-Jason Simanek
Gimp-developer mailing list

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