Message
Re: Lightroom and QTR for Windows -- advice for an export for QTR strategy
2016-02-10 by rdeloe1@...
Anyway, I did know that Gray Gamma 2.2 and AdobeRGB are effectively the same as far as workflow goes. But I also thought both are curved spaces; I believe that’s what Roy is saying in the link Brian provided. I think that’s also what Paul Roark is saying in his Eboni-4-Plus.pdf document, which I quote here:
“QTR is not, in and of itself, ‘color managed.’ That is, it does not automatically adjust the output to match the working space or embedded profile of the image file such that the relative densities displayed on the monitor will be reflected in the print…. If a file is edited in Gray Gamma 2.2 it will not result in a print from QTR that looks like the monitor. Because the GG2.2 shadows are compressed and QTR shadows are linear, a GG2.2 file will appear lighter and perhaps lacking in good blacks when printed with QTR.”
It’s this insight that led me to trying the approach I described here (i.e., getting the image “right” on my calibrated monitor in Lightroom, then exporting with a linear ICC – Roy’s RGB_Matte_Paper.ICC, and then printing in QTR with attention to Ink Limit values). Note I also tried it with the ICC I made for that paper and ink, reading the L values from a print of a 21 step chart with a known even distribution of gray values; there was no difference to my eye in shadow detail compared to the export with RGB_Matte_Paper.ICC. Exporting with either seems to have lined things up properly in the shadows.
On the three papers I’m using I can get consistent prints with this kludgy technique, and critical shadow details are being nicely preserved. My own benchmark is an image of mine where being even a bit off in the shadows is very evident. If it prints properly, then I’m happy.
Unfortunately, kludgy approaches like this suffer from the problem of reproducibility across media… and mine is no exception. For two Premier Art papers, this approach works consistently well (Fine Art 205 gsm and Smooth Bright White 200 gsm). Export with RGB_Matte_Paper, and print in QTR with Ink Limit -15. The results are great and consistent.
But… I just profiled my Premier Art Smooth Fine Art 325 gsm (still using Paul Roark’s “generic” Eboni Variable Tone curves linearized for this paper). I can get excellent results that totally match the other two papers in the shadows… but for this 325 gsm paper (same printer, same inks, same image inside Lightroom) I have to export with Adobe RGB and print from QTR with Ink Limit = 0. I can’t begin to explain why this is the case.
In the end the only thing that matters to me is that I can get reproducible high quality results for specific ink and paper combinations, so I shouldn’t be too concerned that something is happening that I don’t understand. But I won’t deny that I’d prefer to know what’s going on!