profile conversion different from softproof?!?

[rsamco]

Maybe someone can shed some light on this ... I have an image in ProPhotoRGB that has very saturated yellows that changes markedly when I softproof it (using CS3) using AdobeRGB, and even more radically when softproofed using sRGB.  Just as I expect the yellows get much less saturated as the gamut gets pulled in.  However, if (again in CS3) I convert the image to AdobeRGB or sRGB (I also convert it to 8 bits), I see only very minor changes -- nothing close to what softproofing using the same profiles shows.  Anyone know why this is?  TIA

Rick

[colourperfect]

The answer may lie in the rendering intent used for the conversion. When you softproof, really intended for printer profiles not colourspaces I think, you have a choice of rendering intents. When you convert the colour space from prophoto to sRGB or AdobeRGB the Adobe colour engine does this for you.

Go back and check whether changing the rendering intent of the softproof makes a difference. Also check the state of the paper white / ink black check boxes

Ian

http://profiles.colourperfect.co.uk

[digitaldog]

Go back and check whether changing the rendering intent of the softproof makes a difference. Also check the state of the paper white / ink black check boxes
http://profiles.colourperfect.co.uk
[a href=\"index.php?act=findpost&pid=119738\"][{POST_SNAPBACK}][/a]

If he's indeed soft proofing or converting from simple matrix profile to matrix profiles (that sounds like what he's describing if I'm reading this correctly), the only possibility for use is the Colorimetric intent (there's no Perceptual table). Photoshop allows you to select it, but that's now what you're getting.

Rick, can you clarify what profiles you're using here?

[rsamco]

Andrew, to answer your question ... I'll just focus on the ProPhotoRGB to sRGB pair ...

For softproofing, I used a "Customize Proof Condition" using "sRGB IE61966-2.1" as the "Device to Simulate" with "Preserve RGB Numbers" checked ON.  I am not given the option to choose a Rendering Intent, Black Point Compensation, nor Display Options (i.e., "Simulate Paper Color" & "Simulate Black Ink").

For profile conversion, I used "sRGB IE61966-2.1" as the "Destination Space" with the Adobe (ACE) Engine and a Perceptual Intent (with "Black Point Compensation" & "Use Dither" checked ON).

OK, after checking all of this, I went back and set up a new custom proofing condition using "Preserve RGB Numbers" checked OFF.  Now I'm given the Rendering Intent and Black Point Compensation options.  Now I get the same results as for the profile conversion.  So it was pilot error -- I didn't realize that I had checked "preserve RGB numbers".  Why would anyone want to check this on anyway?

Thanks for forcing me to carefully check what I had done!

Rick

[digitaldog]

For softproofing, I used a "Customize Proof Condition" using "sRGB IE61966-2.1" as the "Device to Simulate" with "Preserve RGB Numbers" checked ON. I am not given the option to choose a Rendering Intent, Black Point Compensation, nor Display Options (i.e., "Simulate Paper Color" & "Simulate Black Ink").

What are you trying to accomplsh? The Preserve RGB numbers is an option to show you how the current set of values would appear going out to the profile you select if you DID NOT convert. IOW, show me how ugly the document would appear if I sent these numbers to the device but didn't use the device profile. I'm confused about what you're hoping to see.

[Schewe]

For softproofing, I used a "Customize Proof Condition" using "sRGB IE61966-2.1" as the "Device to Simulate" with "Preserve RGB Numbers" checked ON.[a href=\"index.php?act=findpost&pid=119805\"][{POST_SNAPBACK}][/a]

Then you are missusing soft proofing...as Andrew stated, preserving RGB numbers will _ONLY_ show you what the image would look like if you didn't convert but assigned the ProPhoto RGB as sRGB. You almost always and only want to preserve appearance-that's what color management is all about-preserving the appearance of images through different color spaces and devices.

Obviously, you are gonna get whacked out colors if you assign PP RGB images an sRGB space. That's what "Convert" is all about.