Non-DI RC papers?

Discussion in 'B&W: Film, Paper, Chemistry' started by Paul Verizzo, Mar 15, 2008.

  1. Paul Verizzo

    Paul Verizzo Member

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    I see that Photomek..whatever Varycon has no developer incorporated into the emulsion.

    Are there any others?

    I've also picked up on assorted web pages that the glossy version of Varycon is not so glossy. True?

    Thanks!
     
  2. Ole

    Ole Moderator Staff Member Moderator

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    I don't think there are any DI papers left - those were made for rapid processing in high-volume labs, which has been completely replaced by d*g*tal. Just like the repro industry.
     
  3. Paul Verizzo

    Paul Verizzo Member

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    I thought Foma was, for instance.

    Ilford RC? Kentmere? No? (I wish I could insert Kodak and Agfa here.....)

    And why would Varycon make note of that if no DI was now the norm?
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    Ole;

    In spite of Ilford's comments, MGIV tests positive for ID.

    PE
     
  5. Paul Verizzo

    Paul Verizzo Member

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    Wish I could type....

    "None other DI RC papers?"

    Don't know how my fingers did that. Should have been something like "Are there any other none DI RC papers?"
     
  6. srs5694

    srs5694 Member

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    I don't know about DI, but Fotokemika Varycon's glossy seems about as glossy as other papers to me -- or at least, I didn't notice much difference in the few sheets I've printed. (I only bought a 25-pack of 8x10-inch sheets out of curiosity, and I don't have a sample in front of me.) It seemed hard to get a good rich black out of it, but maybe I just needed more practice with it.
     
  7. dancqu

    dancqu Member

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    Freestyle carries one, a Graded RC. Even that requires
    a usual developer. Used for class instruction. I doubt you'll
    find one which responds to the usual developer activator,
    sodium carbonate.

    To test expose a piece of paper and develop it in
    a weak solution of that carbonate. Dan
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    Dan;

    Many activators were Sodium Hydroxide or Sodium Phosphate to get the desired pH value that would unblock the developing agent. Many developing agents are blocked and require this stronger alkali for activation. Therefore, they fail the test with dilute carbonate. Strong carbonate, or one of the above that I mention would be better.

    PE
     
  9. Simon R Galley

    Simon R Galley Subscriber

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    Dear All,

    Whilst I would never refute Photo Engineer, in terms of his experience and knowledge and also would never, ever doubt his test results, no ILFORD Photo paper has developer incorporated.

    Simon ILFORD Photo / HARMAN technology Limited :
     
  10. Ian Grant

    Ian Grant Subscriber

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    The early Ilfospeed paper was developer incorporated, something Ilford kept quite quiet at the time as they were selling Ilfospeed processing machines. It was processable in the earlier Ilfoprint machines but for best results required a modified Activator. I processed many thousands of prints usingactivator and Hypam in place of the stabiliser in the late 70's early 80's until Ilford changed the emulsion.

    Once the emulsion formula was changed the paper was no longer suitable and that was the end of my machine processing.

    Ian
     
  11. Photo Engineer

    Photo Engineer Subscriber

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    Simon;

    Since I don't know your formulation, I cannot comment with authority. Lets just say that Ilford MGIV darkens rapidly when light fogged then treated with an alkaline solution. Kodak paper does darken even more so than Ilford paper. Many other papers do not. For example, the Kentmere papers I have all fail to test positive.

    So, there appears to be a reducing agent there somehow that is forming silver. The intention may not be for development, but it does test positive. The test, of course, detects any reducing agent which acts on silver halide, and which is also the generic and broad definition of a developing agent.

    PE
     
  12. Photo Engineer

    Photo Engineer Subscriber

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    I've been pacing the floor here trying to figure this one out.

    It is probably the case where an addendum in the paper, added there for one reason or another, can give a false positive with the fogged paper + alkali treatment test. That is the only explanation for the results.

    So, I would like to warn you that this test can give false positives. AFAIK, it cannot give false negative tests as long as you use strong alkali.

    PE
     
  13. Photo Engineer

    Photo Engineer Subscriber

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    Simon;

    Here is an interesting test. I coated some of my Azo emulsion which I know has no developing agent or reducing agent in it. I then took 3 pieces of paper, namely:

    1. Kodak PCIV
    2. Ilford MGIV
    3. My 'azo' work alike.

    In the light I placed about 5 drops of 4% Sodium Hydroxide on each.

    Results: Kodak paper blackened instantly, Ilford paper blackened slowly and the droplets took on a visible orange or lemon color. The paper I coated did not change.

    Now is the interesting part.

    I held the Ilford paper over my paper and let the orangish drops of Sodium Hydroxide run off onto my paper from the Ilford paper. My paper instantly began to blacken.

    So, this looks like strong evidence for a 'developing' agent in Ilford paper and it is so strong a reducing agent that it can cross develop other sheets. IMHO this represents a difficult case for processing mixed batches of paper then, if there can be crosstalk between paper types.

    So, I know I am not going crazy!

    PE
     
  14. Paul Verizzo

    Paul Verizzo Member

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    And despite some previous posts here.....

    Kentmere and Arista II (same, of course) actually state that they have a DI, although the statements are a bit cryptic.

    Arista II:

    "Coated Emulsion Layer:
    The light-sensitive silver halide emulsion layer has a silver content of approximately 1.5 g/m2 . This is covered with a gelatine supercoat which protects the emulsion from stress fogging and physical damage, as well as containing a developing agent. (Machine processable but can not be used in activator/stabilization processors.)"

    Kentmere says the same thing.

    So, yes, Virginia, there definitely are DI papers still out there.......
     
  15. dancqu

    dancqu Member

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    You and I have pointed out that some papers
    have DI supercoats. Freestyle states that their
    Arista EDU.Ultra has a DI emulsion. With that
    it is still not activator developable.

    The issue is more complex. As PE has alluded,
    there may be substances, 'reducing agents', which
    might be considered developing agents under certain
    circumstances. These suspects may or may not interact
    with the processing chemistry.

    I believe that Simon is correct in a real world context.
    Also Freestyle, who a few years ago assured me that
    NONE of their Graded papers have DI emulsions.

    I've tested at least a half dozen emulsions and not
    found by a straight carbonate test any to show even
    a trace of development.

    In the Freestyle example the purpose of the
    DI emulsion in that one Graded paper is to speed
    the students along. As for DI papers; activator
    process, no developer needed.

    As for myself, I do test; expose then develop in
    a weak sodium carbonate solution. Beyond that
    the matter is purely academic. Dan
     
  16. Paul Verizzo

    Paul Verizzo Member

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    I think you hit the nail on the head, here.

    The original intent of my post was to avoid having a developer in the emulsion interfere with my chosen developer intentions.

    It looks like it just won't happen.

    Thanks.
     
  17. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I'm not so sure it won't interfere. It is said that older papers were more amenable to developer controls and to toning than many modern papers, and the presence of reducing agents in the emulsion may be partly responsible for that. Another factor is probably the pre-hardening of modern emulsions.
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    David, you are right. Modern papers are formulated in a much different way than the older papers and one thing in particular is true. You cannot easily 'push' a modern paper. They basically stop development when done. Older papers continued to gain contrast and speed and fog. That isn't to say that modern papers do not, just that they 'resist' change beyond a certain point.

    PE