ColorNeg (erstwhile NegPos) and color spaces

<p>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.</p>

<p>However, negatives are a different story and I found out I get satisfactory results <strong>only</strong> by using CF Systems ColorNeg. I purchased a registration key last night.</p>

<p>However, I don't completely understand how ColorNeg handles color spaces and profiles.</p>

<p>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?</p>

<p>Is there any setting buried somewhere in the UI that let's me choose the output color space?</p>

<p>It's only a plugin and does not do colour management on that level. It's still just a PS document for your purpose.</p>

<p> </p>

<p>So does it mean I can just assign the ProphotoRGB color space after it has pulled up the gamma?</p>

<p>There hasn’t been a real solution for profiling for color negs since day one. The exposure effect on the orange mask and a number of other issues make it nearly impossible to build a profile as you can for transparency. So various scanner drivers come up with their own internal method of encoding the data which is what you should stick with. I don’t know what scanner driver you’re using. LaserSoft does an excellent job and would allow you to encode into any RGB working space it supports, including ProPhoto RGB.</p>

<p>Arnab: I would convert, not assign. But the answer is yes.</p>

<p>Andrew: I have *never* seen a scan program perform that task to my liking. I prefer the linier raw scan to ColorNeg/Pos approach. It lets each software be the best at what they do well. As for Lasersoft, I don't care for their approach.</p>

<p><em>"Arnab: I would convert, not assign. But the answer is yes."</em> Peter C<br>

Peter, I just noticed ColorNeg automatically converts (or maybe just "assigns") the currently active working color space. In other words, if I have ProphotoRGB working space, after OK'ing out of the Colorneg filter dialog I see the image has the ProphotoRGB profile attached.<br>

<br />Question is -- that the recommended workflow?<br>

I think the key question here is which profile best interprets the color numbers that ColorNeg comes up with after pulling up the gamma and other adjustments?</p>

<p>I don't think it really matters. I never noticed what it would be before I ran the plugin, as I always convert it before I save (I do the rest of my edits in LR),</p>

<p>In the meantime, I have had a couple of email exchanges on this with David Dunthorn, author of ColorNeg.<br>

Looks like the workflow I am following is alright but I had missed one key piece which he pointed out -- setting the "Gamma C" value for the target color space. In my case for ProphotoRGB (which has a gamma of 1.8) -- the Gamma C had to be changed from 2.2 to 1.8.<br>

Hope this helps.</p>

<p>Yeah, I have a complete 1.8 calibrated environment. I do mostly QTR printing and that's what it uses. I set it a while back, and it keeps that setting for everything I do.</p>