Pyro Developers, Stain and its importance compared to Edge Effect and 3D Relief
Could you please list me all variations of stain colors from Pyro Developers ? And I want to know how much percent is this stain color important to vary and separate the visual tonal difference on print when there is the 3D relief and its result the edge effect ?
Tanning (not the stain per se), edge effects and the relationship between them are complex topics and there is a lot of misinformation. It also depends on the emulsion and developer.
As for stain/dye colour, it generally varies from brown to orange-yellow to yellow to yellowish-green.
Last edited by Michael R 1974; 01-05-2014 at 06:09 PM. Click to view previous post history.
Even influence what type fixer used, as if acid removes the stain
Michael and Xuco , thank you.
Michael , I take tanning effect as 3d relief in gelatin layer proportional to tone. May be I am wrong. But It seems to me such a thin relief could not elaborate to such difference. Rotogravure process - printing press technology which National Geographic Magazine uses at USA - uses dots tones with either dot width and dot depth in the copper cylinder. Their dot depths are faraway more than the pyro relief and with that technology , it is even print every page stunning is difficult. It seems to me an illusion but may be edge effect is the most important.
I want to know what do you think.
ps. at rotogravure dot depth , cylinder gets more ink and print wider tonal range and deeper tones.
ps2- may be its off topic but I am thinking , preparing a digital negative with different color dots where their light diffusion or transparency controlled , there would be more tone and control. I did not hear anything as digital semi transparent dot or paper optimzed color dot.
If you share your idea , I would be happy.
I'm not entirely clear on what you're asking or what you are specifically trying to achieve. First, is this about optical printing of B&W negatives, or using a relief image on a negative in a transfer process (litho for example)?
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I am asking if pyro developed negative is really spectacular when there is such a thin relief - 3d relief -in gelatin ? I am saying when there are such deeper relief technology-rotogravure-, is it possible to give such a honor to thin relief ? May be such a success is the result of edge effect not thin relief at pyro ?
Rotogravure , rotational gravure , there is a gravure carved in to the copper printing press medium , not optical photograph printing process but magazine printing process from gravure to the paper. Gravure depth is variable and so ink transfer to the paper.
My third point is if we make our digital negative dots , colored and semi transparent , what happens.
Thank you and good night.
I found this thread about Pyro interesting. Nicholas Linden tested how the staining color is reputed to affect variable contrast paper in a special way. My take on this study is that there is a real effect... so it's not a delusion. But the effect is very subtle - the kind of effect that a sensitive artist may be able to take advantage of pictorially. But so little that a scientist might rule it out as a normal process variation.
Once again reaffirms my contention that we have all lost 50% of photography when the graded papers were all discontinued in favor of the VC variety. I despise VC paper. Makes printing a ..... (speechless here). I just plain don't like it.
PMK negatives at least show a slight 3D relief similar to old Kodachrome slides. I do not believe it has any effect on the image when printing, as you seem to imply. It is simply a side-effect from the tanning developer. What ever made you think that the slight relief of a negative developed with a tanning developer was a factor in image reproduction. I have never seen any such suggestions.
Stain color itself for PMK is an orangish-yellow (bleach the silver out of a few pyro negs and you can see just the stain). Different developers, different films and even different batches produce slightly different stain colors. I use exactly the same Formulary PMK in the USA and in Europe and the negatives from the same film (320Tri-X) have different stain color. I'm not sure why; perhaps water quality.
There's a lot of misinformation running around about whether or not stain color affects VC contrast. Mr. Linden has laid this pretty much to rest. If there is an effect, it is small enough as to be unimportant.
I develop sheet film in PMK in trays and agitate once through the stack every 30 seconds for the first half of the development time and once every 60 seconds for the second half. Edge effects, i.e., Mackie lines of varying density between adjacent areas of different density, are apparent in my grain focuser and, in my opinion, the characteristic that lends pyro negatives their "look."
I am a bit unclear as to what you are trying to get at. Perhaps you could explain a bit more clearly.
The tanning properties of a low-sulfite Pyro developer are complex and there are various effects - depending on the film and developer formula. But the relief effect itself is not something that would have any appreciable use in normal optical printing of tanned negatives. The relief image can have other uses though - but the "strength" of the relief image has a lot to do with the film, developer, and process.
Originally Posted by Mustafa Umut Sarac
Briefly, tanning both hardens the gelatin and reduces its solubility in water. With a suitable film and process (for example exposing the "matrix" film through the base), you can than wash away the unhardened gelatin, which leaves you with a stronger relief image. Transfer printing plates could be made this way and various complex processes based on this principle led to dye transfer, technicolor, etc. However the materials and developers are specialized, and none of this has anything directly to do with optical printing of B&W negatives.
In optical printing of B&W negatives which have been developed in a tanning developer, the favourable imagewise tanning effect typically claimed is restrained highlight development resulting in increased definition. The low-sulfite content of tanning developers is said to contribute to increased definition due to low solvent effect, and the resulting imagewise dye formation is said to reduce perceived graininess (relative to other non-solvent moderate pH developers) in two ways: 1) dye spreading between developed silver and 2) the dye represents optical density, meaning less silver is required for a given optical density.
The dye mask generated is of limited use for B&W contrast control in standard optical printing with VC papers and depends on the colour, the amount of imagewise dye formed and the printing paper. I don't know of any "process" by which current tanning/staining developer and general purpose B&W films are used to locally control printing contrast. There are however, hybrid processes used for local contrast control: A normally developed B&W negative is scanned. Colours are applied selectively to areas of the image (usually varying amounts of yellow and magenta) and the resulting "colourized" negative is then printed on some sort of suitable support. What you then have is a B&W negative with built-in local contrast filtering.
Does this help at all?