RE: [APML] Photoshop color profile help

["R. Scott Ireland" <ireland@gate.net>]

Dale,

Assign profile does exactly what it says - it assigns a profile to an image,
the color space profile information can then be embedded with the image when
the file is saved.  It does NOT convert colors from one color space to
another.  You would use this, for instance, if you had an image that you
knew was created in a certain color space, but it came without an embedded
profile. You would then "assign" it a profile for further color managmement
purposes.

"Convert to Profile" actually re-maps color infomration from one color space
to another.  This is the one that gave you different colors in your example.
When using Convert to Profile, you are given a choice of rendering intents
(the algorithm for mapping colors from one color space to another).  If the
source space has a lot of "out-of-gamut" colors compared to the destination
space, you may want to use a "Perceptual" rendering intent.  If the color
space gamuts are not widely different, "Relative Colorimetric" may work
best.

Good luck with it,

Regards,

Scott

R. Scott Ireland
Ireland Companies
ireland@gate.net

> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org]On Behalf Of Dale Ireland
> Sent: Wednesday, March 17, 2004 12:29 PM
> To: APML (APML)
> Subject: [APML] Photoshop color profile help
>
>
> I have an astrophoto I want to print at Costco. I can download the .icc
> color profiles for the various papers at my Costco (this is a very nice
> service). I am not sure how to apply the profiles to my images.
> Photoshop has two options, "assign profile" and convert to profile". They
> both seem to do the same thing. When I choose one the colors
> shift somewhat
> and I have to do some adjusting to regain proper color balance. Then,
> regardless of which of the previous two options I selected, I
> save the image
> with the Costco icc embedded. Is this the correct way to do it?
> What is the
> difference between "assign" and convert"??
> It is helpful to do this because the new profiles reveal how much narrower
> the color gamut is for the papers than the color spaces we
> normally use when
> adjusting the images on-screen.
> Dale
>
>
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