ICC color space conversions

I've got a bunch of RGB images. We can assume they are all
tagged with an
ICC profile, but that the color space (and thus the profile)
in each image
may not be the same.

Using imagemagick convert, I need to generate Web-ready
JPEGs for each.
This means applying a -resize, some -unsharp, and handling
the colorspace
conversion from whatever each image's colorspace (ICC
profile) is to a
standardized colorspace (sRGB).

I'm trying to understanding the -profile option in convert.
I see many
examples where two -profile "someprofile.icc"
options are specified in a
single convert command. I'm assuming this is to specify a
*source* (first
profile) and *destination* (second profile) color space for
the
conversion.

My question is this... if I use a (simplified for this
example) command like:

convert /path/to/image.tif -profile "sRGB.icc"
/path/to/output.jpg

Will convert automatically perform a conversion from
*whatever* profile is
embedded in a given image to the specified profile? Or do I
need to first
extract the embedded profile, and then use a command like:

convert /path/to/image.tif -profile
"extracted.icc" -profile "sRGB.icc"
/path/to/output.jpg

Hope this makes sense.

Best,

Rh

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Ok, I got a response (offlist), the gist of which is that if
the  
source image has a profile, then a single -profile
"target.icc" will  
convert from the source image's profile to the specified
target  
profile. This is what I was hoping.

However, in (quick) further testing, it seems that this is
the case  
for TIFF and JPEG, but not for PSD files. Can anyone confirm
that  
Imagemagick is unable to read ICC profiles from PSDs?

A simple demonstration is to take an image and save it to
both PSD  
and TIFF (with the same ICC profile in both). These images
should be  
a perfect colorimetric match in an ICC aware image editor.
Then run  
them through the same convert command, such as:

convert source.psd -profile "target.icc"
output-psd.jpg
convert source.tif -profile "target.icc"
output-tif.jpg

If PSD and TIF were both supported (with respect to ICC
conversions)  
then both of the output JPEGs should be a perfect, or at
least nearly  
perfect, match. Alas, they are clearly not, at least on my
end.

Is this a known limitation with the PSD support in
Imagemagick?

Best,

Rh
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