Dmax Exposure Time on Paper vs ICC Profile


#1

Dear All and Walker

How are you?

I have been working hard on looking for the “best timing” for obtaining Dmax of Beggar COT 320 paper in the past days for Palladium print. I follow exactly the instruction as state in the manual and reviewed so many times…

Finally, I guess i should use 360 secs in order to obtain maximum black of the paper (originally, i use 300 seconds and can get pretty good photo print out, but since i want perfect print out, perfect in a sense means… i really want to obtain maximum black in my photo).

3 days ago…i output the negatives (2 different negatives, one with limiter and one without, both curve were linearized by Excel smoother tool). I let it sit for 24 hours…and then do the “developing out palladium process” in my studio. I used 360 seconds as exposure time, and all the workflow are standardized.

Then i use the print out for producing ICC (of coz i let the paper sit for 1 day again)…

Now, in front of me…it seems the print out is a little bit darker than the monitor when i use the specific ICC for soft proof for each print under Photo soft…(just a little bit, not a lot)

Actually, my core question is: it is not difficult to obtain information about maximum black of a paper (because those are patches and i can easily use a densitometer to check the Dmax without solarization) …but when it comes to print… how come the print looks a little darker than my monitor.

Would anyone teach me a little bit on this??? what is the relationship between getting maximum black and PiezoDN “calibration”??

Thanks a million in advance…

Harris


#2

Your proper exposure time should be determined before anything else in the calibration process. If you change it after you’ve linearized, your result will no longer be linear. In this case, it sounds like you have increased exposure time by 20% from 5 to 6 minutes. That is a significant change, and the result you are seeing, a print that is darker than you want, is exactly what I would expect.

There are no shortcuts in getting a good calibration/linearization, and the steps must be done in a particular order because each one affects the next. If you decide to change something in an earlier step, all subsequent steps need to be redone too.

For an ICC to function predictably, it must be used in conjunction with the .quad from which it was derived. Are you sure you are doing that?

You mentioned making one neg with limiter and one without. I don’t get this. All .quads are limited. Are you using one of the IJM supplied .quads, or have you made a custom one? Since Walker has designed the master .quads for Pt/Pd, you really shouldn’t have to tweak the limits unless you are using a process with a very different exposure scale. The slight variations that result from different ratios of Pt and Pd are not significant.

There is no relationship between getting maximum black and PiezoDN calibration. Maximum black occurs only where there is clear film. It is independent of calibration in this or any method of making negatives.

The effect of using an ICC profile in conjunction with your linearized .quad is to darken the image overall with increased contrast through the midtones into the shadows, but at the expense of compressing the deep shadows (from ~90% to 100%) towards black. In my personal opinion, the effect is too strong resulting in the loss of deep shadow detail that I prefer to keep. This is a matter of personal taste. Have you tried printing the image without the ICC, using No Color Management with the same .quad?

By the way, I have found it very useful to run the linearization process twice in order to get a really good linearization. The attached graph shows each stage of my linearization process: base (master), first linearization, second linearization, and ICC from first linearization. Not shown is an ICC from the second linearization which, as expected, was identical to the ICC from the first.

[attachment file=1275]
Hope this is helpful.


#3

Dear Keith

Thank you very much for your answers. Let me clarify my workflow:

  1. I use Berggar COT 320 paper and try to find out the maximum black…i did 2 test…one use 100 seconds as increment…and the other use 90 seconds as increment… (the reasons why i did this is because i discovered that my previous print out did not get maximum black). that’s why i decided to do another calibration all over again.

  2. finally, i decided to use 360 seconds based on the paper test… i even use an EXACT densitometer to check the paper back (Pantone company lend it to me : )

  3. Of coz…i follow the whole instruction as stated in the PiezoDN manual…and do linearization using the 129 i1Pro2 targets…and loaded the workflow for getting CGats LAB values… and then use the Smoother tool to smooth it…this time i use strength 4… Both curve us Walker’s PD IJM PD curve…one of them is limited and the other one is not…i just want to see the difference… because when i print the 256 target…i discovered that there are more than one patch is pure white… and i guess i should limit it. Any my final limit number is 251 / 244.

  4. after that…i printed another 129i1Pro2 negative…and paper print another piece of print out…using 360 seconds …( i use 360 seconds as decided from the beginning…) for ICC purpose

  5. I calibrated my Dell U2713H (99% adobe color)…using D50… luminance 100 or 120… (of coz before Step 1.

  6. Then i try to print a photo to test the result vs monitor ICC… it seems the print out is around 1/3 stop darker…

Harris


#4

Dear Keith

thank you very much for telling me that if i use ICC…the shadow area from 90 to 100 percentage…will be even darker…then i think i will try to print another negative to see the results…

i use both ICC under Print Tool and select my custom .quad during printing under PRINT TOOL FYI.

Harris


#5

Dear Keith

How can i do linearization twice??

Do you mean once the first linearization is done…then i use the linearized curve to redo the whole process again?

Which means…i should use the second 129 patch print out to do linearization AGAIN…instead of using it for ICC purpose??

Harris


#6

Harris. That is correct.


#7

Dear Keith

Any recommendations on monitor profiling using i1Pro2?? should i use D50 or D55, and should i set luminance to 80, 100, 120???

Please advice.

Harris


#8

Hi Harris -

One of the beauties of PiezoDN is how easy it is to make an adjustment to a previous adjustment. I have run through the linearization process now on 2 printers with different inksets - a 1430 with K6 Selenium and a 3880 with K7 Carbon, and 3 different papers - Arches Platine, Hakkinshi (a lovely thin Kozo/Gampi paper from Japan), and Gampi Torinoko ( a heavy-ish Japanese paper with a lot of texture that I have chosen for my current project). The Japanese papers are very tricky to profile. On none of them did I get a good enough linearization on the first attempt, but on all of them the second iteration (built on the first) was as close to perfect as I think is possible with a hand-coated process. And the Platine linearization that I posted above is the best I’ve ever seen. The ICC is made from the linearized .quad, and I guess it is designed to fit someones idea of how tones should be distributed. I’m not so sure I like the effect, but I’m going to try it for a few weeks side-by-side with non-ICC’d negs and see if I have a consistent preference in the prints. I may end up using the Curve Adjuster tool to customize it to somewhere between them.

So yes, make a new neg with the 129-step using the first -lin.quad (No Color Management), print it, read the results, and use that to make a second linearization. Name it -lin2 or something like that.

About your monitor profile, I use a Spyder rather than i1, so I am not familiar with the X-rite software, but I think 100-120cd may be too bright. I used to set my Eizo (and Dell before that) at 80cd. Walker suggested 85cd which is what I’ve been using for last few months. Switching between the 2 it’s hard to see a difference. Somewhere in that range might encourage you to lighten your shadows a bit in your files, which could be why your prints now look darker than you expect. My black level is 0.5cd, white point is set to 5700K, and Gamma is set at 2.20.

Hope this helps. Hope it makes sense!


#9

Dear Keith

Thank you so much for your detailed explanation.

I am trying to use the first .quad print out to do another linearization now… : )

Many thanks

Harris