about LIMITER Number


#1

Dear Members

I have some questions about PiezoDN.

I’m Japanese, so I’m not good at English.

There is a part which I do not understand in the description of the manual.

First I determined the minimum exposure time for Plutinum Print and printed LIMITER.TIF with that exposure time.

For example, suppose that there are 245 slightly toned parts of the photographic paper.

I do not understand how to calculate LIMIT Number from this number.

There is another question.

In contrast to printing LIMITER.TIF and PiezoDN - 129 step - i1Pro1.tif with no color management in Print - Tool, why use Print color management in normal printing?

Please teach it in English as simple as possible.

My equipment

EPSON 4880

i1Pro2


#2

Dear Yoshifumi. The limiter target is only for the highlights.

To fine minimum time for maximum black simply place OHP Pictorico Ultra Premium Film over a strip of coated paper and expose in increments from under exposure to over exposure. Mark the increments. Where you see the print solarizing it is over exposed. Usually I will go and actually measure these increments with a spectrophotometer because sometimes my eyes can’t tell exactly what is blackest.

Keith (the top contributor on this forum currently) uses the classic Stouffer strip method over the film. This is quicker and can be more precise.

best,

Walker


#3

In contrast to printing LIMITER.TIF and PiezoDN – 129 step – i1Pro1.tif with no color management in Print – Tool, why use Print color management in normal printing?

The reason for choosing to use color management (printing with Default_PtPd.icc in Perceptual mode) is to simulate the contrast of your monitor in the final print. All color-management does is match the print to your screen. This is really an optional thing. I think many people who are familiar with the flat and open tonal scale of Pt/Pd prints actually prefer to print a truly “linear” image (aka no color management). Because of the limited contrast of the medium itself (not a dark black) a perfectly linear platinum print will look much lighter than your monitor, especially in the shadows. The result of a perfectly linear Pt/Pd print is actually very “classic.” It looks like a Pt/Pd print should look.

Others prefer to exactly match the Pt/Pd print with their monitor and that is where the ICC profile comes into play.

best,

Walker


#4

Thank you, Walker. I understand that LIMITER.TIF ​​is for highlights, I also know that I found the minimum exposure time. What I'd like to ask is how to find LIMITE number in highlight. I am sorry that my English is not good.

The Piezography Manual 2017 Deluxe Edition P108.

Suppose, for example, that a patch that prints LIMITER TARGET and looks a little tone is 240. 241 is pure white. Subtracting 4 from 241 is 237. Is this LIMIT number?

one more. In item J, "Set the INPUT to 251 and

The OUTPUT to the LIMIT number. "

Where did you derive this 251 number?

Best

Yoshifumi


#5

Thank you Walker

I understand that LIMITER.TIF is for highlights,I also know that found the minimum exposure time.

What i’d like to ask is how to find LIMIT number in highlight.

ThenPiezograohy Manual 2017 Deluxe Edition P108.

Suppose,for example, prints LIMITER TARGET and looks a little tone is 240.

241 is pure white.Subtracting 4 from 241 is 237.Is this LIMIT number?

Another question.

P108- J, "Set the INPUT to 251 and The OUTPUT to the LIMIT number. "

Where did you derive this 251 number?

Best

Yoshifumi


#6

First questions: Yes, 237 is the limit number. Set the input to 251 and the output to 237.

Because photoshop does not allow for any input data-point higher than 251 in the curve, this is how I came up with the INPUT number. Because this input number is (4 points less that the top input (256) we must also minus 4 points from the output (241 - 4 in this case).

Best,

Walker

 


#7

Thanks Walker ! I understood!!