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Thanks Paul, it seems like I envisioned.. in my otherwise ignorant world.Do all transparency materials work just as well as another, or are there some better than others for this specific purpose?
It's amazing that there are so many different opinions as to Photo/Matte Black, Epson driver/QTR, AB&W, PDN, Chartthrob...it really confounds the beginner. I'm willing to do the work. I just wish there was a baseline that could be "in the ballpark". Maybe one of the ones above will do that for me.
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QTR -- The advantage of QTR is that you can adjust the profile to give as much UV blocking density as needed. The problem is that in order to carry out the tests and make the adjustments you really need a UV transmission densitometer, which very few people have.
Sandy King
Sandy—
I respectfully disagree that you need a UV densitometer to make QTR profiles for digital negatives. A UV densitometer is a convenience, especially if you are making several of these profiles as I sometimes do. But in my QTR Manual I go through the whole process without using a densitometer. Instead I use a contact print of a step wedge negative to assess UV blocking ability of a particular ink setting (not too different than what the PDN system does).
My own guess is that a beginner would find the PDN system easier to wrap his/her head around than the QTR approach. In the long run, however, I think that QTR offers the ultimate control over a printer’s inks. And thus offers the chance, at least, of making a superior negative (although you might not be able to see any difference on a forgiving surface such as Pt/Pd).
Ron Reeder
Ron,
I am not in disagreement with you as to the fact that one can make QTR profiles without a UV densitometer. It just seems to me that it would be much more complicated to do so, which is why I remarked one "really needs a densitometer." But I recognize that it is not absolutely necessary. But since I have a UV densitometer I have never had to try to make a profile without one. In fact, even when I experiment with PDN or the MKS color array the convenience of using a UV densitometer is great compared to contact printing and then examining the step wedge densities. Ultimately the contact print is necessary because UV reading of the colors is not entirely reliable.
Also, I am in agreement with you in that QTR offers the ultimate control over the printer's ink. However, even though I have a good understanding of how to create and modify profiles I still have not found something to put my hat on in terms of accurately predicting how a change to the profile will modify some of the tonal values, especially those in the middle. Hitting the maximum UV blocking density is pretty easy, but getting the tones in the middle right has been very tricky for me. And very time consuming too, I might add.
Sandy
I would agree that QTR offers the most control, but I find this the most difficult method. Creating QTR profiles is an art. Personally, I have had much more success making paper prints using QTR than negatives. I'm sure I could get this to work for me if I invested more time. The simplest process I have found is:
- find a printer/inkset that *does* provide sufficient UV blocking
- print negatives using all inks (composite black) with the native printer driver
- linearize with a Photoshop curve (transmission densitometer required)
I am currently using an Epson R1800 to print my digital negatives. This is only a 13" printer, but I make small prints so this works for me
I'm curious, has anyone ever successfully used someone else's QTR profile for digital negatives?
I'm curious, has anyone ever successfully used someone else's QTR profile for digital negatives?
I've posted a few curves on various threads, but quickly became breathless with all of the particulars of my workflow, and felt a little silly in the bargain.
Case in point- I recently had to return a 3800 and was surprised that I had to start over when the new printer arrived. I got head banding with the old inkset profile and had to tweak the k boost and dark inks to get around it on the new printer. It seems they are subtle enough variations even within the same printer to make curve sharing ultimately unfriendly, to say the least.
Naturally, every time I make a new batch of carbon tissue I run a test with Charthrob to fine tune results. I don't have to do anything for vandyke or palladium because I always work with the same chemistry, but carbon needs the constant updates because of variation in tissue, most of which are deliberate.
Sandy King
For QTR, fine tuning means fiddling the dark ink limits up and down until they just give you pure white at their darkest. Then redo the gray curve, if needed, to get things linear. Doing a gray curve is no harder and takes no more time than making a regular Photoshop .acv correction curve (well, alright, it does take maybe 30 seconds more fiddling with pencil and paper).
With regard to Sandy's stated problem with getting the midtones correct in QTR -- if your profile gives you a linear response with a step tablet negative -- and I usually do not find it very hard to get to that point -- then problems with the midtones lies somewhere else in your workflow. So seemeth to me.
Cheers, Ron Reeder
Ron,
The problem with adjusting the internal curve in QTR is that if you don't get it right the first time it is necessary to step back and create an entirely new curve. There is no mechanism for adjusting the internal curve to fine tune results, or is there?
Sandy
My experience has been that it is impossible to predict exactly how a tweak in the QTR profile would impact output. For me, this results in endless poking and retesting, and not much printing. I also find that it is far easier to tweak using a Photoshop curve.Ron,
My problem is definitely not workflow. I have enough control of the carbon process to make repeat prints of a Stouffer TP-45 step wedge and not have variation of more than log 0.05 in any step.
The problem with adjusting the internal curve in QTR is that if you don't geet it right the first time it is necessary to step back and create an entirely new curve. There is no mechanism for adjusting the internal curve to fine tune results, or is there?
I may be mistaken as to how this work, but my recollection from working with you on several dozen of these profiles is that if the internal QTR profile is not exact you have to throw it away and go back to the original profile without curve to make adjustments.
Sandy
The gray curve tab in the QTR GUI provides a field for importing a Photoshop acv. As far as I know this field doesn't accept number pairs.What about simply adjusting the curve within the QTR profile? I find those curve adjustments very predictable and easy to work with, just like an .acv curve in PS. In the curve creation tool GUI, just enter the number pairs in the curve field under the gray curve tab. Then there's no need to make a whole new curve when tweaking. Sorry if I've misunderstood the problem.
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