You might help me with some questions I have concerning the linearization of the Hahnemuhle paper when printing with a plateburner of 4000 W (630 seconds). The maximum xposure time has been checked and is looking good, with Dmax on all targets printed according to what I obtained in the test strips and Stouffer tests.
Basically, I have started with the Master Curve of IJM for PD only. I have printed the target (v1), made measurements (M1.txt), linearized the master quad > obtaining the v1.quad
The result, that I post here, was way off and typical of plateburners according to our great Keith.
Then I printed a second target (v2) by using the v1.quad, made the measurements (M2.txt) and realized that I had the shadows spot on, but the highlights were a bit off (this time in the other direction, lighter).
As I saw the highlights off, I decided to not stop here, and continue to fine tune the linearization.
What I did was to smooth the measurements M2.txt, and relinearize the v1.quad > obtaining the v2.quad.
I then printed another target (v3) by using the v2.quad. I made the measurements (M3.txt) and I obtained now the shadows a bit off (lighter) and the highlights off in the opposite direction (darker now!).
My two questions are:
Is this normal, that after a while curves start playing tennis as we check the linearized values?
What could be happening in my case?
When does one stop linearizing in succesive steps like this? Are we supposed to control the final results and stop only when the results are perfectly linear? Basically, I understand that once one linearizes the quad file based on the last measurements, in theory we should have the system taking care of the deviations from that moment on… but then, I guess if we reprint with the last linearized quad and measure, we should arrive to spot on linear values, right?
My other question concerns the creation of the ICC profile. If you want to obtain and apply the ICC and you have run more than one “round” of linearization, can you obtain the ICC based on a measurement, AND also linearize the quad curve based on those same measurements?: What I mean, is doing the following thing: print first target with master .quad - print Pt and obtain measurements M1.txt - linearize master quad based on M1.txt - obtain quad v1 - print with quad v1 - print Pt and obtain measurements M2.txt - relinearize quad v1 based on M2.txt - obtain quad v2, AND THEN also obtain ICC profile from the very same M2.txt that you will use when printing with the quad v2. In the manual, it is suggested you linearize based on M1.txt, and then obtain the ICC based on M2.txt… basically then, printing with quad v1 (obtained with measurements M1.txt) and using the ICC (based on measurements M2.txt. I just wonder whether, once you have the measurements M2.txt, it does not make sense to fine tune a bit more the quad curve by linearizing these values too…even if you did it just to obtain the ICC like they explain on the manual. I hope you did not go mad with this explanation!
Thanks so much in advance for your help!