Pyro Developers, Stain and its importance compared to Edge Effect and 3D Relief

[Mustafa Umut Sarac]

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 ?

Umut

 

[Xuco Martin]

Even influence what type fixer used, as if acid removes the stain

 

[Mustafa Umut Sarac]

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.

Umut

 

[Mustafa Umut Sarac]

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.

Umut

 

[Bill Burk]

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.

(there was a url link here which no longer exists)

 

[Tom1956]

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.

 

[Doremus Scudder]

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.

Doremus

 

[Mustafa Umut Sarac]

Doremus and Michael,

Thank you very much.

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.

Michael , That was what I was after to invent and been invented long ago. I was not aware of it because DPUG is at other planet and I rarely visit there.

Now , the big question , you can print colored areas on bw digital negatives to control the local contrast. I understood that. But is there such a thing print colored dots which will affect as semi transparent or controlled transparency dots. I never read anything about hybrid processes and I dont have any idea if there was such a process ?

Thank you,
Umut

 

[DREW WILEY]

Tanning is really a huge subject that goes way beyond currently popular black and white techniques, into dye transfer and Technicolor, and
numerous less familiar obsolete color printing methods, and even into medical applications. You might want to get ahold of some serious photo chem textbooks from the relevant eras. And now hybrid tweaks can hypothetically go all kinds of new directions. But you do need to differentiate tanning relief per se from the concept of image stain, which might or might not be related.

 

[Mustafa Umut Sarac]

Drew,

I need to find a term to use at search engines for finding the wildest applications on tanning. If that is medical application , there might be lots of pdf articles. How do I need to search ?

Umut

 

[DREW WILEY]

Your initial keywords should be something like "gelatin tanning", "gelatin crosslinking", and obviously, "tanning developers". Recent forays into
medical gelatin might involve traditional chemicals, or some very nasty expensive things that I certainly wouldn't want to fool with.