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  1. #11
    MDR
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    A small correction the higher the agitation the higher the contrast not the sharpness. Constant agitation lowers sharpness.

  2. #12

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    Quote Originally Posted by MDR View Post
    A small correction the higher the agitation the higher the contrast not the sharpness. Constant agitation lowers sharpness.
    Thanks for the correction. So, sharpness is mostly depending on the dilution, where for example 1:25 would give a sharper result than 1:50?

  3. #13
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    Quote Originally Posted by Rikard_L View Post
    Trying to summarize what I think I learned and understand so far:

    1. The higher the dilution the lower the overall contrast (all other things equal of course)
    -- 1:25 or 1:50 will give me a higher global contrast than the one I get from stand dev at 1:100.
    Not really, though that would be true if you did not adjust your development time. When you dilute the Rodinal more, you need to develop longer but (assume you use appropriate times), you will get the same overall contrast for differing dilutions.

    The main purpose of changing dilution is to obtain (or not) compensation and adjacency effects, which both depend on local exhaustion of the developer. Read this.

    Quote Originally Posted by Rikard_L View Post
    2. I donít mind grain, but I donít want the grain to dominate too much.

    -- The higher the agitation frequency the more grain.
    -- 1:25 will yield sharper grain than 1:50.
    Not really. The appearance of grain is mostly related to how much total development (contrast) you do. Whether you develop at 1+25 or 1+50, as long as you develop to the same contrast, you will get the same grain. Rodinal is not very flexible with respect to grain, unlike solvent developers like D76 that have a softening effect when more concentrated.

    Rodinal ALWAYS gives you sharp grain.

    Quote Originally Posted by Rikard_L View Post
    3. Resting time between agitation will mostly affect the shadows.
    -- An interval of 2 minutes will push the shadows more than one of 1 minute.
    Pretty much. A better way to think of low-agitation approaches though is this:
    - shadow speed relates mostly to total time spent in the developer, because shadows don't exhaust the developer much so agitation doesn't have much effect
    - highlight density (therefore contrast) is related to the total amount of agitation performed during development

    In the extreme, you can do continuous agitation for example. Development times are pretty short (remember, total agitation matters) otherwise your contrast goes too high and you get a fair bit of speed loss (about a stop) because the total development time is short. Traditional agitation (first minute continuous, then a couple inversions once a minute) will give you a bit more speed but the photos won't look *that* different. Semi-stand can give you a lot of speed, but you run the risk of photos looking quite dead and flat, especially in the highlights, for example.

    Personally when I want film speed, I don't use Rodinal; the fact that you need to do stand development (and what that does to the highlights) to get a speed increase out of it puts me off. Instead, I use faster films and speed-increasing developers (TMY2 and Xtol). I use Rodinal when the quantity of light is no issue, so I can use slow fine films that don't show much/any grain, and I use continuous development to get maximum highlight contrast.

    Stand development can give you adjacency effects but they aren't very visible on medium- and large-format images, so I don't care so much. It matters much more in 35mm but there are easier ways of getting more sharpness (change films!).

  4. #14
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    The first thing to keep in mind is that the grain size and edge effect differences you may see are visually entangled with contrast rate. What I'm saying is that the basic characteristics of the film developer combo controls the grand majority of the look. Changes in dilution and agitation are useful for fine tuning. The effects you can see with a microscope may or may not matter in the print.

    The second thing is that there are always competing priorities. Higher contrast can make a print look sharper. Nice sharp visible print grain can make a print look sharper too, because it gives the viewer's eye something to latch onto. Every characteristic contributes to the print, when you change one you change the rest.

    The third thing is that a negative is normally just a storage medium. Placement of any point, on any negative, can be printed black or mid tone or highlight, period, but relationship between that point and the rest of the subject matter in the negative may or may not be what you want.

    The camera can only give you one exposure setting at a time but your main subject may need one setting and your background another to get the "subject placement" you want in the print.

    Changing placement, like getting shadows darker in the print in relation to the main subject can be done in a variety of ways; less camera exposure, adding artificial light on the main subject in the scene, burn and dodge when printing... Adjusting film development can change the global placement relationships, by say bringing all the whites and all the blacks closer to the mid tones too but that has its limits, it doesn't change the basic relationships between subjects.

    Here's a resource that may help with understanding the global changes http://www.apug.org/forums/forum216/...-negative.html
    Last edited by markbarendt; 10-11-2013 at 05:56 AM. Click to view previous post history.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." AnaÔs Nin

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