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  1. #71
    Bill Burk's Avatar
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    Quote Originally Posted by Michael R 1974 View Post
    I don't know, I'm reading a lot of very questionable things regarding exposure, film speed, shadow detail etc. here.
    I think you're reading a lot of subjective information describing film speed... Where you are more familiar with interpreting sensitometric descriptions.

    For instance what I hear when David Allen writes about increased speed with sacrificed shadow detail, sounds to me like something I define as "pushing". Everything he says makes perfect sense in that context. While I wouldn't categorize it as a real speed gain, the resulting prints have a look that many photographers love and the fact is you use a higher Exposure Index setting. So - no matter what you call it - I accept the discussion as a valid description.

    When I think of "speed loss" or "speed gain", I think of a sensitometric comparison of film developed to ASA gradient 0.62 in two different developers - standard and the comparison - and the comparative shift of the curve where it crosses 0.10 density above base & fog. I'd expect a real speed loss if I took a standard developer and added Potassium Bromide or omitted Metol. I also expect a real speed loss from decades-old film - due to the fog which some films acquire with extreme old age.

    I expect Michael R 1974's tests could show us the real speed loss or speed gain in different combinations of time in solution A and concentration of solution B of Barry Thornton's Two Bath Developer. And I would expect MrBrowning and David Allen could enjoy some real rewards from the graphs because they could help answer the original question, what combinations will achieve N-1 and N+1 development. Personally, I'd use a standard developer for N+1, but it's helpful to have full family graphs with some overlap.

  2. #72
    Rudeofus's Avatar
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    Quote Originally Posted by Bill Burk View Post
    And I would expect MrBrowning and David Allen could enjoy some real rewards from the graphs because they could help answer the original question, what combinations will achieve N-1 and N+1 development. Personally, I'd use a standard developer for N+1, but it's helpful to have full family graphs with some overlap.
    Mr. Browning already stated, that he reused Bath B about 15 times. Michaels test charts are most likely made with fresh soup, so they will not replicate Mr. Brownings results. Mr. Browning's perfect recipe would most likely be: "Use the same recipe as before, but replace bath B after a few rolls of film. If negs are important, use a fresh bath B."
    Trying to be the best of whatever I am, even if what I am is no good.

  3. #73
    baachitraka's Avatar
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    If negs are important, use a fresh bath B."
    I may know how important this statement is...
    OM-1n: Do I need to own a Leica?
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  4. #74

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    Quote Originally Posted by Bill Burk View Post
    I think you're reading a lot of subjective information describing film speed... Where you are more familiar with interpreting sensitometric descriptions.

    For instance what I hear when David Allen writes about increased speed with sacrificed shadow detail, sounds to me like something I define as "pushing". Everything he says makes perfect sense in that context. While I wouldn't categorize it as a real speed gain, the resulting prints have a look that many photographers love and the fact is you use a higher Exposure Index setting. So - no matter what you call it - I accept the discussion as a valid description.
    I'm thinking about it all within the context of tone reproduction in the print. We'd have to discuss David's assertions in post #57. Film speed is a means to an end - securing the required shadow detail. And as you know, detail = local contrast.

    David would have to show that a developer such as DDX is actually losing speed from a tone reproduction perspective, similar to the push analogy you made. But this is not the case. A developer like DDX shortens the toe slightly (compared with say D-76), and in Zone System parlance, Zone 1 is nearly on the straight line. There is an increase in deep shadow detail.

    I think all David can really say is he prefers to downrate the film because he develops to a lower-than-normal gradient for less burning at the printing stage, which results in a loss in effective film EI (I'm not saying this is necessarily true either, but most of us do it anyway). The issue of "blown highlights" is also an interesting one.

    Having said all that, I have found two-solution procedures such as D-23+alkali, BTTB etc. can help preserve "effective film speed" (ie based on a fixed density point) in low contrast processing. Just to get back onto that original topic, the experiments I ran on some of these things was aimed at determining which variables constitute effective controls from a sensitometric perspective. To briefly recap, generally to reduce contrast while preserving EI, reduce development time in bath A. Keep it simple.
    Last edited by Michael R 1974; 06-23-2014 at 08:29 AM. Click to view previous post history.

  5. #75
    David Allen's Avatar
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    David would have to show that a developer such as DDX is actually losing speed from a tone reproduction perspective, similar to the push analogy you made. But this is not the case. A developer like DDX shortens the toe slightly (compared with say D-76), and in Zone System parlance, Zone 1 is nearly on the straight line. There is an increase in deep shadow detail.
    Michael, I couldn't comment authoritively on DDX or the other developers that I mentioned simply because I have not used them enough. For many years I exclusively used HC110 but, as my subject matter changed (from natural landscapes to urban landscapes), I was unhappy with the results I was getting and so set out to test a bunch of other developers. Generally, I found none of the developers that I tested provided any particular advantage over HC110 in terms of shadow detail, tonality, etc. The one developer that did stand out for me (i.e seemed most suited to my way of working) was a two-bath developer formula (based on a replenishment system). This (rather complicated formula) then became my standard developer until I came across BTTB developer. This gave me the same results as the other two-bath developer but with the added benefit of it being very simple and cheap to make.

    I think all David can really say is he prefers to downrate the film because he develops to a lower-than-normal gradient for less burning at the printing stage, which results in a loss in effective film EI (I'm not saying this is necessarily true either, but most of us do it anyway).
    I have no idea if I am developing to a lower gradient as I do not undertake sensometric tests. All that I can say is that I process in each Bath for 5 minutes and this gives me negatives that print very easily of Grade III when using an Ilford 500 diffusing head on my enlarger. The prints demonstrate a full range of tones with minimal requirement for dodging or burning. In general, I print on a slightly harder grade for exhibition prints as that is the look that I prefer.

    Click image for larger version. 

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    In this example, placing the shadow area under the barbed wire and the underside of the lamp on Zone III placed the white wall in full sunlight on Zone IX - X. Nevertheless full detail was retained throughout on the negative. When I did my first test print (using my tested minimum black time) the shadows and highlights demonstrated both detail and good micro-contrast. For the exhibition print, I did a bit of graduated burning-in on the left side to make the image more balanced and did a bit of burning-in on the bottom right corner to give that area a bit more weight.

    I would have thought that, if I was developing to a lower-than-normal gradient, then the image would not demonstrate such a dynamic range and the feeling of intense sunlight. However, as I stated earlier, I am not one to do technical tests with a densitometer but fall in the camp of those who prefer practical tests out in the field (no disrespect for Michael and the others that test differently - it is just how I have always worked).

    David.
    www.dsallen.de

  6. #76
    Bill Burk's Avatar
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    Quote Originally Posted by David Allen View Post
    I would have thought that, if I was developing to a lower-than-normal gradient, then the image would not demonstrate such a dynamic range and the feeling of intense sunlight.
    Looks like a print from a well-exposed negative that was developed to a normal gradient... I would bet that you have so much shadow detail that if you look at the negative, you could make out the shape of the light bulb.

  7. #77
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    Quote Originally Posted by Bill Burk View Post
    Looks like a print from a well-exposed negative that was developed to a normal gradient... I would bet that you have so much shadow detail that if you look at the negative, you could make out the shape of the light bulb.
    Hi Bill, that is what I am thinking. I presume that full development in BTTB should give a normal gradient - although I have no way of testing this.

    For web use, I re-photograph my exhibition prints with a Sigma SD9 and then adjust to match the prints as well as possible. However, I am well aware that everyone's monitor is different (generally I find that the images tend to look slightly darker and slightly softer on Windows machines in comparison to my Mac). Nonetheless, I would think that the overall dynamic range would come across.

    Visually, the exhibition prints tend to look quite contrasty (think perhaps of Adams' later printing style or the typical difference between tonal taste in more eastern parts of Europe / Japan and that of the UK, France, etc) but you can see detail in both the shadow and highlight areas.

    Here are two details to show the shadow information from the original SD9 copy of the exhibition print.

    Click image for larger version. 

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    Click image for larger version. 

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    Bests,

    David.
    www.dsallen.de

  8. #78
    Rudeofus's Avatar
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    Quote Originally Posted by David Allen View Post
    Hi Bill, that is what I am thinking. I presume that full development in BTTB should give a normal gradient - although I have no way of testing this.
    The term "gradient" assumes that your density curve is a straight line, and that is most likely not the case with two bath developers. You get normal to high contrast in the shadow regions, and decreasing contrast as you go towards the highlight sections.
    Trying to be the best of whatever I am, even if what I am is no good.

  9. #79

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    Quote Originally Posted by Rudeofus View Post
    The term "gradient" assumes that your density curve is a straight line, and that is most likely not the case with two bath developers. You get normal to high contrast in the shadow regions, and decreasing contrast as you go towards the highlight sections.
    Maybe but please see the HD's kindly provided by Michael, for his post bath experiments

    posts #45 & #53 earlier

    Not what Id have expected either

  10. #80

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    Two-solution development tends to straighten the curve, giving a more constant slope. You can see one illustration of this in post 53. Note the two-solution curves have a longer straight line than straight D-23 1+3, while the slope of the straight line sections of the curves are virtually the same.

    It is worth noting this as a difference between two-solution development and compensating developers in cases where one is developing to low contrast (note this is a different case from the one in post 53 - ie: no, D-23 is not a compensating developer). Two-solution processing tends to retain the straight line rather than exhibiting "compensating" action (ie lengthening the shoulder). Sandy king wrote an interesting article about this in View Camera some years ago. It was about the utility of both two-solution and true two-bath development for negatives destined for scanning - a case where presumably a straight line negative is then easier to manipulate with software. For wet printing, a straight line negative might or might not necessarily be ideal, depending on the subject matter, printing practices, desired tone reproduction, etc.

    With respect to N+, N, N-, etc., again, with this type of two-solution process where development occurs in both baths, you can achieve whatever contrast you want by shortening or lengthening the time in bath A. Agitation in bath B can also have an effect depending on alkalinity. Remember that with BTTB, D-23+alkali bath etc etc, bath A is a functioning developer on its own. So you can develop to whatever contrast you want with this process. Lots of flexibility. By giving 5 minutes in bath A, I suspect David is getting normal contrast. Perhaps even slightly higher than normal. This would have to be tested.
    Last edited by Michael R 1974; 06-24-2014 at 10:21 AM. Click to view previous post history.



 

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