One of the problems with using a wide-gamut profile like ProPhoto is that you get all kinds of gamut compression issues when you try to export back to something more 'real'. LR uses ProPhoto internally I recall. In the preferences under external editing, you might find PS CS5 is set to AdobeRGB. This is a confusing dialog and you have many other settings for other editors using the combo box below the PS one. You need to configure and save each one individually.
As far as I know you have no control whether LR uses Perceptual or relative colourimetric conversion processes. Which, if you care about colour are pretty significant reason to just not bother with LR at all. If you print large format, I can give a whole bunch of other reasons to dump it.
The only way you really have any form of control is if you never leave LR in the first place. So go through the whole workflow, to print from within LR. This would mean, C One -> TIF. Edit the TIF in PS or wherever else, then finally put it into LR. If you want to re-open the TIF in PS (for printing or further editing) you need to edit the original file in the popup (sorry I cannot test it now to tell you the precise term).
- Paul
Not sure where you are getting all of this, and why you think AdobeRGB is more "real", but this isn't very sound advice. Just because ProPhotoRGB contains "man made" colors doesn't make this a "non real" working space. ProPhoto (originally ROMMrgb) was specifically created to make sure it could contain any natural occuring color. Because it expands that far it does encompass other colors, but that doesn't affect the actual color data of your files or make it "unreal".
The size of a color space has little to do with anything other than whether it can contain all of the colors of the file. The working space is simply a container, and the key is making sure the container is actually large enough to contain the data without having to compress or clip it to begin with (which is what happens if you go from a camera to AdobeRGB). In the workflow all colors are viewed via an appropriate transform through a profile regardless of output device (monitor when editing, printer, etc) , the intent of which is to make various output devices look similar. As such the key is not having to do any transform into a permanent space until the file is purposed. The correct workflow is to always stay in 16bit/ProPhotoRGB for all files unless the file is specifically created with an end purpose in mind (such as sRGB for web). At that point correct processes to convert to the output space included whether to use relative or perecptual intent can be made, including tools such as soft proofing to determine which method delivers the best results. Whether you compress all the data to preserve color relationships into the output space (perceptual), or clip the out of gamut colors into the output space (relative) really needs to be a decision based on visual feedback. But in the workflow if you move from ProPhotoRGB to AdobeRGB as your working space, you will clip the colors, you can't get them back, and you don't accomplish anything positive.
There is no reason to knock LR, because it manages colors very well. It is important that when moving from LR to PS you stay in full 16bit/ProPhotoRGB space so the colors are not modified at all.
As far as the original poster, whatever the problem sounds like a workflow issue somewhere. An exported TIFF file from lightroom in ProPhotoRGB/16bit should (and does) appear identical if opened in PS. If it doesn't something in your export or PS color management polices is not set up right. Maybe I'm misunderstanding your question/issue.
