Best Practice for Verifying Linearity in Digital Negatives

digitalfilm
pzdn

#1

I just made the conversion to Digital Negatives Meth 1 and was wondering what was the best way to verify the linearity I was achieving on my printer with QTR and the Meth 1 curves. Is creating a new greyscale document with a gamma of 2.2 in 16bit then creating a gradation ramp from black to white and printing it in 16bit at 2880 and unidirectional a good practice. Evaluating the smoothness of the ramp visually upon laying the printed film on a white sheet or do I need an evenly lit light table? Or should I be evaluating only the smoothness of a print made from the negative? My guess is that I could simply evaluate the negative but just not sure hoe it’s best to display the negative for evaluation and creating a proper linear scale to test the printing.


#2

If you have installed the inks in the correct positions according to the curves - and there are several versions of curves - and you are using Pictorico OHP or OHP Ultra film - and using QTR to OUR directions rather than the QTR download manual instructions - the ink output will be smooth and linear. There is nothing you can do to adjust that.

This smooth film output is then put into your alternative process and the medium can be linearized through use of a PhotoShop curve.

For silver print, platinum print, carbon print and other alt proc which require similar UV or density blocking, methodology 3 curves are used and five different density curves are available. The final linearization if required is done with simple Photoshop curve.

If your film output is NOT SMOOTH and linear - then something is wrong in your process. Let us know.


#3

Thanks for answering this Jon. FYI, for the most part, the film output is smooth just not perfectly smooth. I can see a little breathing as it moves through the ramp, but it’s a smooth breath. I’ve, since my initial post, purchased a light table to see things a little better so I think it’s good enough for Jazz. But what exactly did you mean when you mentioned above that “there are several versions of curves”? Are you referring to the Meth 1 and meth 3 curves or are there different versions of Meth 1 curves? Also, now that I have installed the Meth 1 ink set, am I correct to assume that I can also print using the Meth 3 curves without changing anything at the printer and achieve the lower DRs? Thanks.


#4

What I meant is that there are actually different versions of the methodology 3 curves V1 V2 that have different ink assignments… Methodology 1 changed as well at some point.

If you can tell me - the actual name of the curve from beginning to end - I can tell you where your ink shades should be by color position.

Meth 1 and Meth 3 are two different ink sets that can not be used at the same time.

Have you referred to our latest manual to see if you are on our current versions? The two methods can not be used at the same time. The new manual is here:

If you are making silver prints - you should be on meth 3. For most alt proc that require very very high density - them meth 1 is better. Let me know what you are using it for and I can advise…


#5

The name of the curve I installed is “PZDN-X800-Meth1” and I’ve installed it on a 4800 EPSON. The alt proc I am currently using this ink set for is “Dye Transfer” printing. I am interested in making enlarged tricolor (RGB) separation negatives for this process. I am currently just testing this process by having someone else make prints from my negs and once I establish the first part of the workflow I will take on the printing part of the process. I currently have sent a set of seps to the printer using the curves “unlimited” to see what results I get and then I hope to adjusted the negs (in photoshop with a curve) accordingly. My guesstimate is that I will be needing the extra density provided by Meth1 for this process but I’m really not sure. Although I did get a “I don’t think I’ll be having any problems with your negatives” upon delivery of my first set of seps. I’m just waiting to see what that means :wink: As for my questions about being able to use Meth3 curves, I was just under the impression (without reading details in the manual) that Meth 1 was an extension of the smaller Meth3 ink set which also swopped in 2.5 and 4.5 into the selenium ink set and that maybe I simply needed to add shade 2 in place of the flushing fluid and I was there. But I’m also considering trying my hands at Platinum/Palladium printing. Would I be needing Meth3 or Meth1 for this process? Based on Sandy Kings’ UV density readings published in the PZ blog, Meth3 densities might be all I need but I’m not sure never having worked with the process. Any ideas? Thanks again -Louis