On 02/08/2010 01:39 AM, Graeme Gill wrote:
> Omari Stephens wrote:
>> Obviously, options for both of these things are "prompt the user." It seems
>> like there
>> should be better alternatives, but I'm not sure what they might be.
>> guiguru? others?
> You're better having a set of defaults that the user can configure,
> so they aren't constantly hassled by prompts. The configuration can
> have options such as "prompt me" for certain combinations.
Yes. By "prompt the user" I meant something similar to the current
behavior when an image is tagged with a color profile other than the
working space profile; the options are:
1) Do nothing
2) Convert to working space profile
3) Prompt the user
I was hoping someone would come up with a better convention, but since
that doesn't seem to be happening, I will rev the spec and mention this
UX paradigm explicitly, with the hope that it will be improved upon in a
>> Author: Omari Stephens<x...@xsdg.org> Version: 1 Date: 3 February 2010
>> 1) When an image is opened with no associated color profile, we assume that
>> it is
>> encoded in sRGB space.
>> c) Convert the image from
>> the implicit profile to some explicit profile (AdobeRGB, ProPhotoRGB, sRGB,
> Not a good idea. There are losses in every color conversion. Ideally you want
> keep an image in its original format, unless the user explicitly decides to
> convert to another colorspace. Input is not the place to do this.
> So the application (GIMP) should have a transformation step available to:
> 1) Convert from one colorspace to another. If an image has no tag,
> then both profiles would need to be specified.
> 2) Assign a profile to the image. This would set or override a tag.
> One idea to consider is the possibility of a "weak color tag". This
> is for a image that is to be considered un-tagged, but has a profile
> to specify the source colorspace for the purposes of display, and conversion.
Your "weak color tag" is exactly what I meant by an "implicit sRGB
profile". My judgment was that it wouldn't be useful to have a "weak"
tag that wasn't sRGB — anything else should be explicit and embedded.
> There should be a "color tag" status somewhere for an image.
Because the only implicit color tag is sRGB, the absence of an
icc-profile parasite (or an empty one) can be considered equivalent to
the implicit sRGB tag.
>> 4) When an image with an explicit profile is exported
>> a) It will be tagged with that
>> profile in whatever way is appropriate for the file format.
>> b) If this is an sRGB PNG,
>> we need to decide between an sRGB chunk and sRGB profile. See later
>> c) If the file format has no way to embed color profile information, (FIXME!)
> For c), have the option to covert to a particular colorspace (ie. sRGB).
Cool. Any thoughts from other people?
> d) Have an option to write the file without an embedded profile. This is an
> option in regard to dealing with other applications, for instance sending
> or profiling files to a particular device.
I was thinking a tiny bit about this, but hadn't come up with anything
conclusive. I'll probably implement something trivial where you can
select a menu item to dump the icc-profile.
>> 5) When an image with an implicit profile is exported a) The image is saved
>> with no
>> color profile information. For PNG, this means no sRGB chunk and also no
>> iCCP chunk.
> You could really have the same options as 4, although you might default them
Hmm; good point. Will think about that.
> There are many possible ways of dealing with this issue. The important things
> I see them are 1) Allow defaulting to logical and useful workflows 2) Allow
> flexibility to accommodate particular needs.
Yup. Thanks for thinking about this.
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