Sharpness and quality of handcoated prints

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by Photo Engineer, Nov 3, 2006.

  1. Photo Engineer

    Photo Engineer Subscriber

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    For the last few days, I have been making comparisons of the sharpness of hand coated prints using my own emulsions. This should also be true using Liquid Light and other similar products.

    Sharpness appears to decrease in the order:

    Baryta > Hot press untextured > cold press > cold press textured

    Sharpness seems to decrease in the order:

    Blade coated/dip coated > spray > brush

    Since I have only done Blade, dip and brush, I cannot comment exactly on the spray coating other than what is published.

    This work is based on making defninition chart exposures of negative and positive images (which reveal bloom and fill in).

    Some of the papers tested include Strathmore, Lanaquarelle, Cranes, COT320, and a host of others including 3 grades of Baryta and RC.

    All are acceptable and yield some spectacular results, espeically the textured Strathmore Watercolor which is simply beyond description for some pictures (but is not very sharp). I think Denise Ross has said it best. These images can be stunning and repeat what some of the old textured surfaces gave us.

    I encourage you all to try making your own coatings on some of the textured papers out there. Please be aware that you must coat more emulsion on cold pressed papers than on hot pressed papers and you must 'learn' how to do this. It is like learning how to paint a picture with extra steps.

    My best wishes to all of you who try it.

    PE
     
  2. dwross

    dwross Member

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    I think I'm finding that the developer makes a difference, too. I'll be more sure of that after a couple more runs of tests. My results this week are up here: http://dwrphotos.com/blog/EmulsionResearch.htm#Current and one date back (Oct 30 - Nov 3)

    I'm with PE in encouraging more folks to work on this. I just finished reading "Memoirs of a Photochemist", by Fritz Wentzel, and I was struck by how the past and future keep circling around each other. In many ways, APUG'ers are recreating the excitement and investigative energy of those early photographers. So much knowledge has been lost and even small machine shops and mechanical skills are getting harder to access. We're pioneers and historians at the same time. Very cool.
     
  3. Donald Miller

    Donald Miller Member

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    Excuse me for asking what seems to me to be obvious. If we are going to engage in hand coating our printing materials, why not go to a known process and go with pt-pd? Or even Kallitype toned in Pt which seems to be indistinguishable from pt-pd.

    The collectors of photographic art will buy pt-pd ten to one over silver.
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    Printing speed, grades, tone, and a host of other advantages.

    But then you might be right.

    PE
     
  5. dwross

    dwross Member

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    A knownprocess? Where's the fun in that? And, if money if the motivation, photography may not be the very best profession to be in. Far more important is this: they are different works of art, as different as watercolor is from oil. Color, texture, appearance, best negatives for the process - all different and in my opinion, viva la.
     
  6. Donald Miller

    Donald Miller Member

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    Certainly true that each has it's own advantages. Pt-pd does have the capability of altering contrast contrary to popular belief. The advantages of Pt-pd are longer tonal scale. The disadvantage, to some, is lower dmax than silver.

    The fun in doing something that is known is not having to reinvent the wheel at each and every turn. I have lived the better part of my time on this earth and would rather spend it making good photographs. But to each his/her own.
     
  7. Photo Engineer

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    Donald, I've often wondered about that. It seems to me that a longer tonal scale and a lower dmax are contradictory, as a longer tonal scale to me requires a higher dmax.

    In any event, if you make your own emulsion you can control the tonal scale rather than take what the manufacturer thinks you should have.

    You are correct about contrast, I had forgotten that, but can you devise a range over 4 grades? You can with silver. IDK personally if you have that range with Pt/Pd.

    And, you can keep the emulsion for quite a long time, as well as the coated paper or film. Can you do this for Pt/Pd? I really don't know.

    I'll probably think of more reasons, but cost comes to mind as well. Silver nitrate costs a LOT less than either Pt or Pd salts.

    PE
     
  8. Donald Miller

    Donald Miller Member

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    Yes, cost is a factor...no doubt about that. But I think that is offset by the higher esteem in which Pt-pd prints are held by most.

    I think that because of the higher cost and perhaps the greater degree of experience/knowledge that pt-pd printers usually possess, that most know how to expose and process the camera negative so that it exhibits repeatable and foreknown density scale characteristics.

    The one characteristic that hand coating silver would offer is that the print would exhibit more of the pt-pd characteristics so far as the emulsion residing within the paper rather than sitting on the baryta layer.

    So far as the requirement of a long tonal scale requiring a high dmax, I don't follow your reasoning on this. The difference in the materials is such that the dmax (whether it is 1.65 or 2.10) is not related to the distribution over which the rest of the tonal scale is represented.
     
  9. Photo Engineer

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    Donald, the tone scale is the total length of the sensitometric curve from where the curve starts to rise above dmin (toe) to where it levels off at dmax (shoulder). If the dmax is lowered, then the shoulder is closer to the toe and the tone scale is shorter. That is the definition I learned at EK with all of the diagrams and technobabble removed.

    PE
     
  10. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I'd bet you that Strathmore 500 Plate finish falls somewhere between baryta and hot press watercolor paper. This is what I'm using for albumen.
     
  11. Photo Engineer

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    David, I use the Strathmore Smooth, as I can't get the Platae. I used the cold press Watercolor. I have not found any hot press. The finish on the cold press is beautiful, but it is hard to coat. I think I showed you some examples of that.

    PE
     
  12. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Yes, I've seen it, and I've also tried some Arches cold press and Arches hot press for albumen and for Polaroid transfers--both very nice papers.

    PM me your address, and I can send you some Strathmore 500 1-ply Plate to experiment with. I've been buying it online from Jerry's Art-a-rama.
     
  13. Photo Engineer

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    David, thanks, but I can order it. I have to get several types of paper support and some film supports as well.

    I really appreciate the offer.

    PE
     
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  15. Kirk Keyes

    Kirk Keyes Member

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    Perhaps Donald is referring to the exposure range...

    I hear people often (just this last weekend actually) say pt-pd has a "longer" tonal scale, much like they say that Azo has a "longer" tonal scale. They seems to be confusing either the exposure range of the paper, or they percieving something that is not backed up by math/physics/optics.
     
  16. Donald Miller

    Donald Miller Member

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    Whatever the correct term is, what I mean is that pt-pd and grade two Azo, for that matter, will require a camera negative with a greater density range than an equivalent grade two photographic enlarging paper. (1.65- 1.70 vs. 1.10 -1.25)

    Yet when we examine the characteristics of prints made from optimally produced negatives, pt-pd will not have the dmax of a silver print. So if you have an explanation for that, I am open to hearing it.
     
  17. Photo Engineer

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    Donald, what are the contrasts of those two negatives though? That is what also enters into the final print. That density range may have been achived by a variation in the negative contrast which makes a big difference in the final print.

    I might also add that both Azo and Pt/Pd have a majority of their sensitivity in the UV region and visual contrast may therefore be misleading even when using a tungsten bulb.

    PE
     
  18. Kirk Keyes

    Kirk Keyes Member

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    This is known as the Exposure Scale. It's the x-axis in your BTZS software.

    This is the Density Scale -From Answers.com:
    A value for the range density for a photographic material that corresponds to the difference between the maximum density and the minimum density. Also known as net density.

    It's the y-axis on the BTZS software.

    You're comparing apples and oranges when you ask that question.

    The Azo and pt-pd paper have a low contrast, hence the greater exposure scale than greade 2 silver paper. Combine this with negatives that have a high density range, and you get a print of normal reproduction range.

    The Azo print will produce the neg with greater d-max than the pt-pd, but the same range of exposure scale is recorded onto the paper. (By the way, my Ilford MG IV FB with grade 00 can print that same negative exposure scale range.)

    I'm sure PE can explain the multiplication of negative and paper gradients/contrasts to come up with a normal reproduction range and how it applies to this question better than I...
     
  19. Photo Engineer

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    Kirk;

    Thanks, you did so well, I don't think I need to add anything, unless Donald wants more detail about curve shapes.

    PE
     
  20. Donald Miller

    Donald Miller Member

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    This still does not answer the position that PE made that higher dmax is necessary for a longer tonal scale. If a material such as Azo Grade two has an exposure scale of 1.65-1.70 and a grade two material such as Nuance has a exposure scale of 1.25 with a condenser enlarger than something is darned sure different. I agree that it takes a negative of corresponding density range (high density minus low density and not minus FB +fog) to match the paper. The paper or process (in the case of Pt-pd is longer scale) or lower contrast in your description.

    By the way, PE, I do understand curve shapes so there is no need for you enlightenment on that score.
     
  21. Photo Engineer

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    Donald;

    If two papers are identical in all ways but dmax, the paper with the lower dmax is necessarily shorter in latitude and will reproduce a shorter tone scale.

    I think that you can see the logic in that. You can demonatrate that for yourself by taking a paper curve from the Kodak web site and altering it to show the two curves.

    Without such curves, I guess this is about all I can do in the way of explanation. I hope it helps.

    There are other curves possible, but this is the simplest case. I hope it helps you.

    Use what works for you or what you like best though.

    PE
     
  22. Donald Miller

    Donald Miller Member

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    I hope that you recognize one thing about this discussion. It is that you have chosen to move it into an arena apart from what my original response and all subsequent responses have said. You are the only one who is placing the qualification of all things "being equal" into this discussion.

    That is the basis of the disagreement that we have. Pt-pd and Azo are not the same as all other papers. I think that you will agree to that. You are making a global judgement based upon a limited view of things.

    I will agree that if all things are equal that certain conditions will exist...but in this case all things are not equal.
     
  23. dwross

    dwross Member

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    Donald: I went back over this thread (much more compelling than going back outside to dig the drainage ditch around our house even deeper. The PNW is flooding. AZ sounds really good right now :smile: The silver gelatin emusion that I (and PE) have been working with doesn't enter the paper in the same way as pt/pd or the salted POP types. When it is applied it looks like white jello - still warm and thin enough to flow. Even though it sits on the paper's surface, it is very durable. I haven't had any peel off or scratch (though I tend to be a tender technician). It is just thin enough to allow the texture of the paper show through. A print coated on baryta paper is very smooth, but the emulsion can be coated on all textures, greatly influencing the character of the final product.
     
  24. Photo Engineer

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    Donald, I am quite familiar with the characteristics of Azo paper. After all, one of my emulsions is a very close duplicate of Azo. I am therefore in a position to state that I have coated the experiment I describe above and can verify that Azo exibits the characteristics that I describe if the curve is controlled as I describe. And, due to my familiarity with a number of other papers, including color, which I have coated, I can say that they all behave the same within their own class and even cross compared if they are made to equivalent curves.

    The result is limited due to physics and we cannot get around the natural laws involved.

    I too love the character of Azo and Pt/Pd, but they behave according to the same laws of reflectance and transmission and can be cross compared under the conditions I have described.

    But, again, I say use what works. That is the underlying theme of everything I propose.

    PE
     
  25. Kirk Keyes

    Kirk Keyes Member

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    I think the first problem here is that "tonal scale" isn't really a precisely defined term. My understanding is that "tonal range" may be more appropriate and is sometimes used here as well. But even then, that term seems not to be well defined.

    The 3rd edition of The Focal Encyclopedia of Photography doesn't have an entry for "Tonal Scale" or "Tonal Range." They do use the term "Tonality" and define it as, "The overall appearance of the densities of the component areas of a photograph or other image with respect to the effectiveness of the values in representing the subject."

    Please correct me Donald, but I think this is what your question is about:
    "Why is a higher print d-max necessary to achieve a print with greater Tonality?"

    If so, then let's look at a print that has a density range of 1.5 (maybe a pt-pd print) and compare that to a print that has a density range of 2.1 (maybe an Azo print). Remembering that one stop of reflection density is equal to 0.3, our pt-pd print can reproduce a range of tones that will be compressed into a reflection density range of 5 stops, while the Azo print will reproduce a range of tones that will be compressed into a range of 7 stops.

    This pt-pd print will only be able to display a "shorter" tonal range than the Azo print, which comparatively will display a "longer" tonal range. So the Azo print will have greater Tonality than the pt-pd print.

    Back to our definition of tonality - "The overall appearance of the densities of the component areas of a photograph or other image with respect to the effectiveness of the values in representing the subject." Note the part about effectiveness of values in representing the subject. That means our eyes have to take part in this question.

    Since our eyes can can't really get much more information out of a reflection print with a greater density range than about 2.1 or so, we can't really get a print that can display a greater range of tonality than really around 7 stops.

    Using Zones as a reference - we probably can agree that there are 9 or 10 zones that can be reproduced in a print. The photographic process does this by compressing the tones. It's the toe, shoulder and overall contrast of the paper and films characterisctic curves that work to our advantage. They compress highlight and shadow densities from the original scene so that they can be reproduced in the range of tones that our printing paper can reproduce.

    Even a material with a relatively low dmax like pt-pd can reproduce a wide range of tones - all 10 Zones even, but it can't do so without reproducing those tones at a reduced visual contrast. It does so by compressing even more than a paper with a greater density range. And of course, if a negative gets a minus development, it can allow the reproduction of more Zones, but again it must be at a lower overall print contrast.

    Whether this meets our need for "effectiveness of the values in representing the subject", is the question to ask next.
     
  26. sanking

    sanking Member

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    Sharpness and resolution are primarily determined by paper surface. The water color and drawing papers we use with Pt./Pd. are simply not able to show much more than 10 lppm, if that. The paper texture simply breaks up any detail or resolution over 10 lppm. Silver prints on glossy papers, on the other hand, are capable of showing resolution well over 40 lppm.

    My carbon prints placed on art and drawing papers do not show nearly as much detail as an image from the same negative placed on a hard surface, fixed out photographic paper.

    Bear in mind, however, that the limit of human resolution is below 10 lppm for the great majority of persons.

    Sandy King
     
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