Pyro negs for VC paper - densitometry

[Jan_6568]

I am doing BTZS tests of pyro negatives to print on VC paper (but I do not intend to use VC filters). I wonder which channel of X-Rite 810 I should read. Visible?

kind regards,

Jan

[Bjorn Nilsson]

Use the blue channel. The paper is most sensitive to blue light anyway.

//Björn

[Ole Tjugen]

VC paper is sensitive to both blue and green light - high contrast blue and low contrast green.

So you really should measure both.

[steve simmons]

I go for a density of 1.35 above fb+fog with the blue channel. However, if I test the Picker way with VC paper and no filter I get that same density for the zone 8 tone I want (just barely perceptably darker than paper white). You end up at the same place either way. This is with PMK.

There is a general article on staining developers and one on the Picker method of testing in the Free Articles section of the View Camera web site.

steve simmons

[Jan_6568]

VC paper is sensitive to both blue and green light - high contrast blue and low contrast green.

So you really should measure both.
Ole, the two channel give different readings with pyro negatives? Would you use an avarage?

Jan

[Ole Tjugen]

Ole, the two channel give different readings with pyro negatives? Would you use an avarage?

Jan

I wouldn't use an average, but record both curves. That would be a good thing to have, since it is by no means certain that the curves would be the same.

I have given up Pyrocat-HD with Agfa APX 100 after getting one negative that prints far too soft on Ilford MG (with full magenta filtration, even), yet has too much contrast for POP! It's nice as a salt print, though...

[Jan_6568]

I have given up Pyrocat-HD with Agfa APX 100 after getting one negative that prints far too soft on Ilford MG (with full magenta filtration, even), yet has too much contrast for POP! It's nice as a salt print, though...

Too soft for VC paper and too contrasty for POP???
I am using only one VC paper, Fomatone MG (w/o filtration), but it is way more contrasty then POP.

Jan

[Ole Tjugen]

Exactly Jan - the stain blocks blue light and lets green through, so the VC is exposed with green only giving very low contrast. Since the POP is not sensitive to green, the stain is added (and proportional) density to that paper, giving very very high contrast. I tried it on graded paper too just to make sure that there wasn't something wrong with the other papers, and got almost pure black and white with no greys on G1 paper...

[Jan_6568]

Yes, you are right Ole. At least in case of Fomatone stain's color does not compensate enough, though.
But probably it is better to give up staining developers with the images intended for VC papers.

cheers,

Jan

[steve simmons]

Staining developers work very well with VC papers. Try something like Tri-X or FP4+.

From what I am reading in this thread you re making things much too complicated. Try the Picker method and use a VC paper without a filter with is about the same as #2. Do you testing here and then you will have a lot of leeway for silver printing and alt process printing.

steve simmons

[Jan_6568]

thanks, Steve,

Jan