Wow...first time I've ever gotten a shout-out on a forum. :blush:
I'm not too familiar with Ron Reeder's method, but I think it's incorrect to say that he is not linearizing. He may not use the Linearization tab, but the correction curve he derives is certainly designed to linearize the negative.
FYI...to be clear, linearizing is the method of correlating the values in the digital image with specific values in the print. Specifically, that luminance (L*) values measured from a printed gray scale, when plotted against each step's gray % (or just numbered from 1 to 21 or whatever), forms a straight line. Together with a calibrated monitor, this ensures the closest possible screen-to-print match, further enhanced by using the ICC creation tool in QTR to create an ICC profile for soft-proofing.
Whether the linearization is done using QTR's linearization tab, through a curve loaded into the curve section of a "Gray Curve" or "Toner Curve" tab, or loaded directly as an ink curve will not make a difference in the final print, provided that each is measured and computed correctly.
Furthermore, it is only very recently that QTR has supported direct linearization of digital negatives (maybe only in pre-release still, you might need to contact Roy Harrington about this). Prior to this, there was some mathematical gymnastics that needed to be performed, whether you were using the "Linearization" tab, or deriving a correction curve file. Ron's method far predates direct linearization in QTR, so he chose to use a curve file. I'll note that the gymnastics that were needed for the linearization tab were nearly the same as for making a correction curve.
Since I figured out how to do those gymnastics for the QTR linearization tab, and now that it supports direct linearization, my preference has been to use that method. It leaves the gray curve field available for curves to alter the tonal relationships in a creative way, as opposed to a technical/analytical (linearization) way. Though my ultimate preference would be to achieve that in Photoshop, since the straight linearized process ensures a fairly accurate screen-to-print match. This is a workflow decision that's up to the user to decide what will work best for him or her.
On occasion, I've also used the gray curve to "pre-linearize" some difficult curves (typically, ones with long toe and long shoulder) by adding just a couple of points to get it closer to linear prior to running another print for final linearization. This helps in some cases where linearization has difficulty with steps that are too close together. (e.g. if your first 4 steps are L*=5, 5.25, 5.75 and 6.25, this might cause some difficulty, and not provide a good linearization, since there is some potential measurement error there, as well.) Visually graphing the measured data helps to see where there might be a problem.
Whether you choose to linearize with the the linearization tab inside QTR, with a curve loaded into QTR, or with a correction curve applied to the image in Photoshop, is purely up to the choice of the user. They all can create excellent profiles and images. Using correction curves even has one advantage, in that it does not require uniformly-spaced measurements (i.e. you can measure at 2%, 5%, 10%, 20, 50, 80, 90, 95 and 98, or whatever). If you do that with QTR's linearization, it will be seriously messed up. Personally, I don't think that's a critical benefit, since we're talking about hand-coated images, with minute variations from sheet to sheet, anyway. But again, that's something you need to decide for yourself.
Best of luck...
--Greg
