When scanning slides I scan into a linear tiff and then assign my scanner's color space (for linear tiffs) in photoshop. Then I do a perceptual conversion to ProphoRGB. However, negatives are a different story and I found out I get satisfactory results only by using CF Systems ColorNeg. I purchased a registration key last night. However, I don't completely understand how ColorNeg handles color spaces and profiles. The input file is 16-bit linear tiff without a color profile, as asked. But after conversion -- what is the recommended approach for assigning/converting to ProphotRGB? Is there any setting buried somewhere in the UI that let's me choose the output color space?