LIMITER.tiff or a different .quad?

PiezoDN Digital Negatives
1

Hi,

I decided to add Ammonium Citrate (AC) as an optional developer for my Pd. workflow. I normally use Potassium Oxalate (KOx).

I first determined the minimum exposure time to obtain max density using the 4x5 Stouffer 21 step chart. FYI AC is a little over 1/2 stop slower than KOx in my workflow. Both developers are used a studio temp. (between 64 and 66 year round); at this time of year RH is 40%-44%. Paper is Revere Platinum.

Knowing my max. density minimum exposure amount I printed the Spyder 129 step chart using my master linearized curve for Revere Platinum paper, 100% Pd., and KOx developer. For reference I have enclosed it.

The first thing I noticed on the print after dry down were extremely bright patches in nearly all the first row. After measuring all 129 steps I determined that the first four or five patches are paper white. I have enclosed this .txt file. I have also enclosed a smoothed version (QTR Data Tool, smoothing = 2. Ffile name appended with S=2).

Here are a set of questions:

  1. Can I use this data set to linearize for AC developer?

  2. If the answer to #1 is no should I print LIMITER.tif and proceed with that workflow OR should I print a new 129 Spyder target using the Pro-PiezoDN-Master.quad? Or some other .quad?

thanks!
Michael

18May2020,7880Pro,Pd,RevPt,2800,20190503,linA,E=4K,AC.txt (2.1 KB)

18May2020,7880Pro,Pd,RevPt,2800,20190503,linA,E=4K,AC,S=2.txt (2.8 KB)

7880Pro-Pd-RevPt-2800-20190503-linA.quad (7.5 KB)

2

Put the measurements into PPEv2 and smooth the data.

Then in the “Falses” column do some fudging like his:
96.92
96.91
96.90
96.88
96.85
96.75
…

3

Thanks Walker for the quick reply. Hope you and everyone at CE / IJM are well.

4

We’re doing well. We are living in a functional state (Vermont) with the lowest covid growth rate in the country. :slight_smile:

best,
Walker

5

So I made a linearization. Enclosed is the text file of the 129 patches (also one smoothed with QTR Data Tool with a smoothing value of 2). I have also included the .quad used (this was the one I made based upon the thread above). As you can see from the data the result is not linear (and lighter from 1/4 to 3/4 tones in an arcing curve).

I know I need to linearize again. I’m also writing this followup to see if you see anything obvious that I may be doing wrong.

thank you,
Michael

20May2020,7880Pro,Pd,RevPt,4K,20200519linA(AC).txt (2.0 KB)

20May2020,7880Pro,Pd,RevPt,4K,20200519linA(AC),S=2.txt (2.8 KB)

7880Pro-Pd-RevPt-4K-AC-20200519-linA.quad (8.1 KB)