I use the same curve for all three separations. I linearized my QTR curve using the traditional cyanotype formula at a 2A:1B dilution @ about 1/2 full exposure ( my typical blue layer ). And then adjusting my magenta pigment & exposure with test strips to get it close to linear, by inspection, with that curve. Yellow was just some trial and error tests with prints, as the step wedges were impossible to read.
I think it was Loris who suggested using the cyanotype curve for all the separations. I like that I only use a single curve and it's close enough.
I use the same curve for all three separations. I linearized my QTR curve using the traditional cyanotype formula at a 2A:1B dilution @ about 1/2 full exposure ( my typical blue layer ). And then adjusting my magenta pigment & exposure with test strips to get it close to linear, by inspection, with that curve. Yellow was just some trial and error tests with prints, as the step wedges were impossible to read.
I think it was Loris who suggested using the cyanotype curve for all the separations. I like that I only use a single curve and it's close enough.
I linearize all three colors. The adjustment curves are all different and color rendition comes out much more precise. My method is to abstract in the computer with Photoshop and then print colors as accurately as possible although I do physical development at times. I build my curves with PDN.
I'm also interested to learn how Keith Taylor uses ICC profiles to print tri-color gum.
I linearize all three colors. The adjustment curves are all different and color rendition comes out much more precise. My method is to abstract in the computer with Photoshop and then print colors as accurately as possible although I do physical development at times. I build my curves with PDN.
I'm also interested to learn how Keith Taylor uses ICC profiles to print tri-color gum.
Don
That sounds like a far more precise accounting, well beyond my simple endeavor.
So are you making the separations and then reassembling them again, with appropriate colors, to check for accuracy and fine tune?
As I recall the article, Keith Taylor really did go to some extremes to fine tune his process. He brought in a specialist to create those profiles for him.
So is your goal to use QTRs ability to create ICC profiles? That would be very cool indeed. I don't see why you could not create a curve for each layer in QTR. Cyan and magenta are easy enough, but yellow just seems to fade into the paper.
If I can get this file printed very accurately with my adjustment curves then I know I'm pretty close.
As I recall the article, Keith Taylor really did go to some extremes to fine tune his process. He brought in a specialist to create those profiles for him.
I'm not sure how the ICC profiles were made and applied. I could print a set of standard xRite/Gretag targets (as tri-color gum prints) and have a friend derive an ICC profile, which I assume I would apply to the image before generating the CMY seps in PS.
So is your goal to use QTRs ability to create ICC profiles?
No I don't think so.
That would be very cool indeed. I don't see why you could not create a curve for each layer in QTR. Cyan and magenta are easy enough, but yellow just seems to fade into the paper.
I don't think a yellow curve is any harder than the others. Remember also I'm using a colorized negative for each separation color. All three maybe different as well as their curves.
A perfect match is not what I am looking for as well, I would really like to see some of your prints, even in jpeg.
Is it possible to contact me via email, bob@elevatordigital.ca
If you are getting good grey card balance and good blacks , I feel you are on to something.
Do you every make a black Mask for detail and contrast?
Originally Posted by Don Bryant
Hi Bob,
The image shown is the reference image from Adobe. I can get very close to this, though I've never been able to get a perfect match.
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Originally Posted by R Shaffer 
