Contrast and pyro developers

[John Bond]

Since becoming familiar with pyro developers, I have understood (or misunderstood) that the proportionate stain acts to attenuate contrast more in the denser parts of the negative than the less dense parts when printed on variable contrast paper creating some degree of highlight compression or compensation. Recently, I have been wondering if this is really true. Variable contrast filtration changes contrast according to the relative amount of yellow and magenta. Does the denser yellow stain in the negative highlights change the proportion of yellow to magenta compared to the less dense shadows or does the actual color stay the same leaving the contrast the same across the entire density range of the negative?

 

[w35773]

John,

A couple of thoughts, but I'm not the best person to answer. I was advised by Sandy King (directly and indirectly) that when using Pyrocat, development time needed to be extended when printing on VC papers. I am certain this is due to the color of the pyrocat stain. Since different pyro developers have different stain colors, I imagine this effect would depend on the type of developer.

 

[gainer]

The contrast on VC paper is lower than on graded paper, but slightly higher than that of the silver image alone. The response of VC paper to blue or magenta filtration of the Pyrocat negative is in the normal direction. A few experiments will tell you all you need to know. You need not change development just for VC paper.

 

[Thomas Bertilsson]

Interesting fact (hopefully). I shot a lot of Tri-X over in Oshkosh, Wisconsin in 2006. I developed all of it in Pyrocat-HD. They are dense negatives (on purpose) and they print nicely on grade 3 paper, while if I use a VC paper, I have to jump to between G3.5 and G4 to get the same punch in the image.
That tells me that the stain has greater effect on graded papers than VC.

Just a thought.

- Thomas

 

[noseoil]

When all is said and done, it still boils down to doing some test method to find the correct film contrast for the correct paper. Try printing an image on a graded paper, then print the same image on VC paper. This should give you the basic imformation about contrast you need to adjust things for a decent image.

I've found I like the effects of Pyrocat stain better than those of PMK, in most cases. The yellow-green general stain from PMK acts as a mask in all zones of the image, making shadows muddy or murky. For portraits I tend to use PMK because it has a nice smoothing effect on skin tones and shadows are not as important to me in a portrait as higher values. For landscapes and industrail work, Pyrocat has a better finish. Just my opinion. tim

 

[George Collier]

My experience re PMK vs Pyrocat agrees with Tim's. Also, no one mentioned (that I saw) the type of bulb. I find that with my Arristo V54 lamp and Pyrocat negs, I keep needing to lower the filter (#0 - #1) to get normal contrast. I could lower the development time, but I can tell by looking at the negs that they are not excessively contrasty, even a bit flatter (to the eye) than my HC110 negs, and I don't want to decrease tonal separation.
I should say that I'm still finding the "sweet spot" between development (30min for FP4, 1.5:1:250, 72F, agitation at the 10 minute marks for the moment) and filtration for this combination, so my opinion may change later. For what it's worth also, I'm using Dupont filters and Forte V fiber, and I may go through this again when I eventually have to go to Ilford paper.

 

[John Bond]

I appreciate everyone's input. It is very clear that staining developers require a higher contrast grade or longer negative devolpment time when printed on variable contrast paper. But, my question is, is this effect greater in the highlights than the shadows.

Sandy King writes in his article on unblinkingeye.com, "When printing with variable contrast papers, pyro stain, which is always proportional to silver density, functions as a continuous variable color mask that reduces printing contrast, particularly in the high values. This allows shadow and mid-tones to be printed without compressing or blocking the highlights, reducing time spent burning and dodging." It is this notion of a "continuous variable color mask" that I am wondering about. Does the increased stain in the highlights attenuate contrast more there than it does in the shadows? Or, another way of asking, does the proportionate stain really have a different effect than a general stain other than to simply build up density?

 

[gainer]

I have a feeling that there will be no satisfactory answer but your own. I don't mean that I think you are being contrary, but that it is a fact of human nature, even if the humans involved are photographers, to have different tastes in such matters as gradations. It will generally be possible for you and me to make photos that have Zones II to VIII of the same subject but with everything between different, and for me to like mine better than yours and you to like yours better than mine.

The effect of a printing filter is not to counteract the effect of a pyrogallol or catechol stain. The MG filter is of constant density everywhere, whereas the stain in the negative is proportional in some way to the negative's silver density.

The effect of a VC filter will not be the same as using the corresponding graded paper, which responds to the color of the negative as if it were some added silver density, nor will either be the same as if a POP process had been used, which is intrinsically self-masking. The VC filter provides an exposure level in the projected image where the stain of the negative and the color of the filter may be thought of as being equal. On one side of that level the filter color begins to predominate while the negative color predominates on the other. While I can use this mental image to estimate quantitatively what may happen when I print a stained negative through a given VC filter, I have not figured out how to predict the effect from density measurements.

Suppose the image color to be yellow and proportional to the negative's silver density, and the filter to be blue. At some value of silver density, the projected image would be neutral. Densities below that, the blue would prevail and the image would be bluer as negative density decreased, thus making microcontrasts, at least, higher in shadows of the final print. The implication is that in order to produce the or nearly the same overall result from VC paper as from graded paper, one should choose a filter whose blue content is such as to cancel the yellow content of the highest negative density. The idea of a certain filter rendering the same contrast as a graded paper thus goes out the window when the negative is proportionally stained. I would expect the filter that would match a print made on grade 3 paper would produce a considerably higher contrast with an unstained negative.