VC Papers + Staining Developers

In his article on Unblinking Eye , Sandy King points out that depending on the color of the stain, we can expect to see different results when printing on Silver papers, both Variable Contrast and Graded.



..."Brown stain blocks green light more effectively than green stain, and for that reason there is much less shouldering in the highlights with Pyrocat HD than with PMK. The result is that prints made with Pyrocat-HD negatives on VC papers will have more contrast in the highlights than prints made with PMK negatives, but there will less compensating effect."



When enlarging Pyrocat HD negatives onto Variable Contrast Silver papers, is the compensating effect basically lost ? - or is there still enough effect to merit the use of a staining developer anyhow ? (I hope the answer is yes, and I am aware of the other advantages: smoother grain, enhanced local contrast, etc).



Thanks !

I had very good luck using PMK and enlarging on a number of VC papers, mainly Agfa fb stuff in Ansco 130. The key for me seemed to be split contrast printing (independent high and low-grade exposures of varying times and ratios). That said, the difference wasn't mind blowing, and I ended up going back to HC-110 as I got tired of developing 4x5 in trays (go Jobo!).

I had a total failure with PMK, an almost brand new kit. It changed colors as I mixed the working strength indicating everything was OK. The negs were almost clear, so I know fix was not used first.

Home made D76 works fine for me. HC110 ok to, but I had a failure with that once too. It was in it`s last month, but a new bottle and the color was ok.

Scratch mix your own. If something is bad, it is your fault. And you know how old it is and it turns color if bad. Use once and throw it away.

BTW, PMK was ok, but nothing special.

if you are calibrating neg development times to fit the paper then by using staining developers, your end result is that the neg scale will fit the paper just as if you were using a non staining developer and had calibrated dev for the paper. There will be differences in the curve shape.
Personally I beleive the most advantage from staining developers is to be had when using graded papers. This was illustrated to me by Barry Thornton at one of his workshops. Take a stained neg and print it on graded paper and VC paper and see the difference. The Graded paper will generally show much more contrast, especially local contrast which gives the print some real kick.

A brown/yellow neg on VC is equivalent to INCREASING Yellow filtration. A green stain is equivalent to REDUCING Magenta filtration. Its not quite that simple because the stain is not linear across the neg.

On VC paper brown/yellow stain reduces local contrast. On Graded paper it increases local contrast.

A green stain does the same on VC paper but on Graded paper(only sensitive to blue light) then it should have little effect.

If you have a stained neg which doesn't have enough contrast to print easily on VC paper then try Graded paper. And similarly, if you have a stained neg which has too much contrast for graded paper then try printing on VC paper.

Ken,
Of course, Sandy probably knows best how PyrocatHD works. What I read in the article you referenced follows my experience in that the effect you are asking about varies with film and technique. I speak about PyrcatHD - I have no PMK experience to compare with.

I found TriX to take a strong orange/brown stain in PyrocatHD while HP5 and FP4 stained very faintly and seemed a different color. And TriX printed -very- differently from HP5, it was not pretty. These observations are from visual inspection of the negatives and making prints, no densitometer here. My results printing with FP4 and HP5 on VC paper showed what might be some compensation effect in the highlights or rather I thought a general depression for lots of my subjects. I like bright skin tones and generally bright high values and sometimes (not always) I felt like my human subjects might be a bit swarthy looking. For "landscapes, peeling paint or rocks and ferns" kind of scenes the result might be just great. I think you'll have to try this for yourself and see if your prints look like what you want.

"When enlarging Pyrocat HD negatives onto Variable Contrast Silver papers, is the compensating effect basically lost ? - or is there still enough effect to merit the use of a staining developer anyhow ? (I hope the answer is yes, and I am aware of the other advantages: smoother grain, enhanced local contrast, etc). "

Ken,

There is no absolute answer to your question because the compensating efffect with all staining developers varies a lot by film, and even type of processing. However, as a general rule, and with most films, you will find that there is still quite a bit of compensating effect in the extreme highlights with Pyrocat-HD negatives when printing on VD silver papers. Much more, for example, than with most non-staining compensating formulas, though less than with PMK.

As I have stated before, the compensating efffect is a two-edge sword with VC papers. It allows control of very extreme highlights, but at the expense of separation in the upper mid tones. Unfortunately, the differences are subtle rather than great, and many people simply don't appear to be aware of them, or how to test the differences.

VC Paper

To understand the effect of a stained neg on VC printing paper, it is necesary to have a basic understanding of the way VC papers work, and of color theory. Both subjects are complex and a thorough treatment of either is beyond the scope of this post, so I'll simplify.

VC papers have multiple emulsion layers; some sensitive to Blue and Green, others only to Blue. Contrast, or Exposure Scale (ES) is adjusted by varying the ratio of Blue to Green. It is important to remember that Green is Blue+Yellow (B+Y), so the two colors we're really working with are Yellow and Blue. More Blue=more contrast. VC papers are relatively insensitive to Red light, which is why it's possible to use a Red safelight.

Stain color.

The stain colors produced by pyrogallol and catechol are generall described as green (Y+B), and brown (Y+R), respectively. Both are oversimplifications, but might prove useful for our discussion. It is helpful to think of a stained neg as a filter. If we start with pure yellow light, we get the lowest contrast, or longest Exposure Scale (ES) the paper is capable of. If we add blue to make green, we get higher contrast/shorter ES. If we add red to make brown, we get longer printing times, but no change in contrast/ES.

The above is an example of additive color mixing, but if we think of a stained neg as a filter, we should think in terms of subtractive color mixing. If we start with white light, we get equal proportions of blue and yellow, and a mid-grade contrast/ES. If we add a green (Y+B) filter, representing a pyro neg, we still get equal proportions of yellow and blue, but block part of the red portion of the spectrum. In theory, we should still get a medium grade contrast/ES, because we've added equal portions of B and Y, but in practice, our pyro negs aren't really 50/50- yellow/blue, but more yellow than blue, which would serve to reduce contrast/ES to some extent. If we substitute our green pyro neg for a brown (Y+R) cat neg, in theory, we get equal parts Neutral Density (ND) because VC paper is insensitive to red, and yellow. In theory the combined effects would be to reduce contrast, and increase exposure time, but this ignores a central component of image stain, which is proportionality. The proportional nature of image stain dictates that whatever effect the stain has, it is more pronounced as siver density increases. Accordingly, the Neutral Density portion of a cat neg's color serves to increase contrast/ES in the same way that silver density does, and the yellow component mitigates this increase to some extent. A pyro neg, on the other hand, serves to decrease contrast/ ES in proportion to density, giving the compensating effect for which it's known and loved.

I am conducting some simple experiments to test these theories, and measure the effects of various staining developers on various VC papers, and will publish my results when I have them.

Jay

In reading my post above, I don't feel I've made my point very clearly, so I'll add the following:

The stain color of either pyro or catechol negs work in essentially the same way. They both produce mostly neutral proportional density, and effect contrast/ES, and therefore compensation to the extent that their stain color is more yellow than blue.

Jay

In a comparison about 18 months ago I tested PMK with FP4+ and also with HD. I liked the PMK much better. The high values with PMK had better separation and I also got a little better shadow detail.

This debate will go on forever with everyone having their favorite anecdotal story to support their conclusions. I tested for fiom speed and normal developing time before making any actual photos. I preferred the PMK. There will be a group of people who prefer the HD.

steve simmons

"In theory the combined effects would be to reduce contrast, and increase exposure time, but this ignores a central component of image stain, which is proportionality. The proportional nature of image stain dictates that whatever effect the stain has, it is more pronounced as siver density increases. Accordingly, the Neutral Density portion of a cat neg's color serves to increase contrast/ES in the same way that silver density does, and the yellow component mitigates this increase to some extent. A pyro neg, on the other hand, serves to decrease contrast/ ES in proportion to density, giving the compensating effect for which it's known and loved."

Jay,

What you write is IMO a very accurate description of the difference between the effects on VC papers of a typical pyrogallol type stain (green) and a pyrocatechin type stain (brown). I hope you will do more experimentation on this and write up your finding somewhere. The subject is of interest to me but because I am primarily involved in priniting on graded silver papers and with alterantive processes I am reluctant to spend the time studying VC silver papers, with with I rarely print.

Folks should understand that the color of the stain only impacts compenasation with VC silver papers. With graded papers contrast, as measured by the appropriate color, is contrast. Negatives developed to the same average contrast in any staining developer (as read by a densitometer in the appropirae color, blue for graded silver papers, UV for alternative processes), will print with the same tonal values on graded silver papers and with any of the alternative processes.

The issue of VC papers versus graded papers with different staining developers was treated by Barry Thornton in his book The Edge of Darkness. In this book Thornton describes and illustrates the difference between the green stain of PMK and the brown stain of his Diaxactol formula (pyrocatechin based) on VD and graded papers. In studying this issue we must also take into account the nature of film curves to determine how much compensation is appropriate. Howard Bond gives some interesting information on this in the article he published in Darkroom Techniques a y ear or so ago in which he compared a traditional non-staining developer with PMK, using several different films.

I encourage anyone interested in studying this effect to read what Thorntoin and Bond have to say and do their own testing. In the end the issue is choosing a developer that best matches the curves of the film to the subject lighting conditions and process. And especially the process, since the preference of someone who works only with VC silver papers is pretty much irrevelant to folks printing on AZO and alternative processes.