Azo like emulsion in several grades

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by Photo Engineer, Dec 6, 2006.

  1. Photo Engineer

    Photo Engineer Subscriber

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    I am now able to make an Azo like emulsion in up to 7 contrast grades. This paper is about 1 stop faster than traditional Azo, and has a spectral sensitivity tilted more to the UV than visible region (less blue, more UV).

    Some of the grades are designed to give a softer toe so that there is a longer tone scale with better highlight detail.

    The range is obtained by use of one emulsion formula, but the use of variations in the final coating formulation, so that there is a minimum of lab work involved. In fact, with practice, you can make up one batch of melted emulsion and make 3 grades from it by adding addenda as you coat to vary the end result. So, make the melted emulsion, coat 10 sheets, add an ingredient, coat 10 more and add another ingredient and coat 10 more and you have 30 sheets of increasing contrast. Of course, by varying levels of these ingredients you can obtain custom results of intermediate contrast.

    I have coated it on 4 types of paper. Strathmore Smooth, Vellum, Watercolor and Glossy Baryta. Difficulty increases in the order given, but sharpness is in the order Watercolor, Vellum, Smooth, Baryta in increasing order.

    A coating defect appears on the left (soft grade) print which is not untypical of coating on Watercolor or Baryta.

    I am posting two samples of a soft and hard grade on Watercolor. This particular paper has a rich surface similar to canvas, so the pattern you see is not a defect, but rather an artifact of the scanning process.

    They were both exposed for 10" and developed in Dektol 1:3 for 1', followed by stop and fix. The fix was an acid hardening fix. I have used a variety of developer for processing this emulsion including the M&P Amidol developer. All work quite well.

    PE
     

    Attached Files:

  2. Sean

    Sean Admin Staff Member Admin

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    very cool Ron. I've enjoyed following your progress :smile:
     
  3. JBrunner

    JBrunner Moderator Staff Member Moderator

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    Very cool.
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    Thanks, more coming.

    PE
     
  5. doughowk

    doughowk Subscriber

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    I'm still holding my breath for Lodima; but this may be an attractive alternative. Looking forward to seeing more results.
     
  6. John Bartley

    John Bartley Member

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    This is very interesting news. I've been following your posts on emulsions and will follow them even more closely now.

    cheers
     
  7. JBrunner

    JBrunner Moderator Staff Member Moderator

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    Yup, this one got my full attention.
     
  8. Kobin

    Kobin Member

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    The progess you've made in the past year is very encouraging. I might be coating my own papers with custom emulsions some day.

    K.
     
  9. MattKing

    MattKing Subscriber

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    P.E.

    1) this is fascinating; and
    2) where did you get the picture of my Dad in his late 20s:wink: (maybe it's the "Kodak look").

    Matt
     
  10. Curt

    Curt Subscriber

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    Well there you go. PE has done it in a method traditional of early scientists. A very high praise to you, and the best of luck and success in your progress.

    Regards,

    Curt
     
  11. Photo Engineer

    Photo Engineer Subscriber

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    Matt;

    It is my uncle who went to Brooks and who got me into photography.

    PE
     
  12. Photo Engineer

    Photo Engineer Subscriber

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    Guys;

    It can be done. The emulsion takes about 1 hour to make with 4 ingredients including distilled water. The final melted emulsion adds up to 2 more ingredients depending on contrast, plus hardener and surfactant. The emulsion keeps for 6 months in the refrigerator if you add Thymol as a preservative. The coatings have kept for weeks.

    This is doable by anyone. It uses methods from the 40s.

    PE
     
  13. juan

    juan Subscriber

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    Does your emulsion have the 3-D look that I was able to get from Azo? I have an Azo print hanging in my office. I bring in prints I've made on other papers to look at them in average room light, but the Azo print hangs on the wall and mocks the other papers' lack of 3-D.

    Thanks for all your hard work.
    juan
     
  14. avandesande

    avandesande Member

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    Nice work PE. I would interested in seeing how the baryarta prints look...
     
  15. Jim Noel

    Jim Noel Member

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    :D WONDERFUL!

    I wish I could get to Montana to take your workshop this summer, but I am already scheduled somewhere else that week. Do yu plan to publish your work in some form? I believe many of us would willingly purchase the information.

    Jim
     
  16. Photo Engineer

    Photo Engineer Subscriber

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    Juan, you would have to get the opinion of some experts in Azo. I doubt it though as I cannot get the Azo paper support.

    PE
     
  17. Photo Engineer

    Photo Engineer Subscriber

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    I plan on publishing all of the work. I have some problems facing me.

    1. I need one more grade of enlarging paper. I can only get grades from 0 - 2. I cannot get a grade 3.

    2. I cannot get a repeatable film emulsion. It varies in fog and contrast and that is probably due to the ammonia digest. There are ways around this, but so far my attempts have failed. I also need more speed. I'm working on a high iodide emulsion at the present time which does not use ammonia.

    3. I'm tweaking the Azo formula to improve results.

    4. I'm tweaking surfactant to reduce coating defects. So far, it can run as high as 50% on baryta and watercolor, but I want less than 10% which is what I get on the Strathmore Smooth. My average on baryta with a custom formula is about 90% good stuff, and the same with watercolor, but I don't want to have a formula for every paper support.

    Thats about it.

    PE
     
  18. Photo Engineer

    Photo Engineer Subscriber

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    I have one ready now.

    If you look closely, you will see the minute dots and imperfections typical of quite a few baryta coatings. I have a very good enlarging paper example, but this one is good because it is the soft grade emulsion, but on baryta.

    This paper will require a slight modification to the coating formula to optimize the result.

    The benefit is greater sharpness and a bit more percieved contrast due to the whiter support.

    PE
     

    Attached Files:

  19. Photo Engineer

    Photo Engineer Subscriber

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    Thanks to all for the kind comments.

    Please, I am not looking for kudos, but rather I'm trying to prove that analog photography is not dead and you can do it yourself.

    PE
     
  20. Petzi

    Petzi Member

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    With your "blade" coating method, how do you achieve even coating of the textured surface?
     
  21. Photo Engineer

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    My rank ordering puts baryta and watercolor at the top of the 'difficult' list. However, with a 'thin' emulsion and slow application with the right surfactant, the emulsion spreads over the hills and valleys of the textured surface papers just fine, but not always. There are a fair number of failures.

    Baryta has problems due to its hard surface after the calendaring process.

    PE
     
  22. juan

    juan Subscriber

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    The thoughts expressed at Michael and Paula's site was that the 3-D effect in Azo came from a combination of the emulsion and development in amidol. Supposedly, the emulsion developed from the bottom up. I'm not sure if this is correct or not - nor do I know, if this theory is correct, whether the development is due to the emulsion or the paper support allowing the developer through from the back.

    juan
     
  23. Photo Engineer

    Photo Engineer Subscriber

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    Juan;

    I find it difficult to believe that development starts from the bottom up in a diffusion limited process. The emulsion always wets from the top down, even on FB support. Development follows the wetting process, downward.

    As for the 3D effect, I wouldn't call it that, but I have seen prints as good as Azo prints on other papers. I think that it depends on the skill of the operator and the care taken.

    PE