Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,205   Posts: 1,531,727   Online: 1057
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 15
  1. #1
    Mustafa Umut Sarac's Avatar
    Join Date
    Oct 2006
    Location
    İstanbul - Türkiye
    Shooter
    35mm RF
    Posts
    3,796
    Images
    108

    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 ?

    Umut

  2. #2

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,606
    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.

    See Haist.
    Last edited by Michael R 1974; 01-05-2014 at 05:09 PM. Click to view previous post history.

  3. #3

    Join Date
    Mar 2013
    Location
    Madrid España
    Shooter
    Medium Format
    Posts
    24
    Even influence what type fixer used, as if acid removes the stain

  4. #4
    Mustafa Umut Sarac's Avatar
    Join Date
    Oct 2006
    Location
    İstanbul - Türkiye
    Shooter
    35mm RF
    Posts
    3,796
    Images
    108
    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

  5. #5

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,606
    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)?

  6. #6
    Mustafa Umut Sarac's Avatar
    Join Date
    Oct 2006
    Location
    İstanbul - Türkiye
    Shooter
    35mm RF
    Posts
    3,796
    Images
    108
    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

  7. #7
    Bill Burk's Avatar
    Join Date
    Feb 2010
    Shooter
    4x5 Format
    Posts
    3,191
    Images
    46
    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.

    http://www.apug.org/forums/forum37/8...-contrast.html

  8. #8

    Join Date
    May 2013
    Location
    US
    Shooter
    Large Format
    Posts
    2,060
    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.

  9. #9

    Join Date
    Sep 2002
    Location
    Oregon and Austria
    Shooter
    4x5 Format
    Posts
    833
    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

  10. #10

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,606
    Quote Originally Posted by Mustafa Umut Sarac View Post
    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
    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.

    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?

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin