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Thread: New darkroom calibration software.

  1. #11

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    Re: New darkroom calibration software.

    Import manufacturer’s data sheets and overlay expected vs actual results.

    I hope this doesn’t sound like trolling, because I think these are all neat things to add and it seems like you are at the stage where you are fleshing out features.

  2. #12

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    Re: New darkroom calibration software.

    Quote Originally Posted by Bill Burk View Post
    I think these are all neat things to add and it seems like you are at the stage where you are fleshing out features.
    Bill, yes, you are rigth... at this stage I find important to realize what potential needs can be there, this would make easier to keep development open for what matters.


    Quote Originally Posted by Bill Burk View Post
    I’d like to be able to read on my densitometer and enter values for each reading. (Support a ‘debugging’ mode if you would like to call it that).
    This is possible yet, as the tool is intended (for the moment) to source data colums to Excel (or other) then the values in the tables tables can be modified there. I find convenient (for the moment) making the tool extract the data and leaving complete freedom to user to organize data in Excel, each Excel tab may contain a different film for example with several graphs in it...

    Densities can be checked in the tool itself, because by pointing any spot with the tool we see the calculated density.



    (Curves in this sample are arbitrary, I copied several times the same image of a single strip, simulating being 4 different, just for development, I made tests and density calculation by referencing to the stouffer is really fine.)



    Quote Originally Posted by Bill Burk View Post
    In some cases users don’t know their Lux seconds. So it would be nice if you work backwards to it. The way I work backwards is to find the curve that met ISO/ASA and from the 0.1 speed point of that curve (and the box speed) deduce the Lux seconds. Also assume users will be a little inconsistent, don’t allow curves to cross but instead slide the exposure axis of misfits and report the exposure deviation.
    Well, as the LUX*Second exposure is introduced then by changing it all the graphs shifts left-rigt, so that could be done by selecting a point of the Normal curve to tell what's the meter point. OK, I understood that...

    lux meters today are $20, but if not having it then that way will allows something better than the "arbitrary units".


    Quote Originally Posted by Bill Burk View Post
    Also assume users will be a little inconsistent, don’t allow curves to cross but instead slide the exposure axis of misfits and report the exposure deviation.
    For the moments all strips share the same exposure to simplify interface, but in the data structure each strip has its own exposure, it would easy to allows to edit particular exposure for each strip, in a sort of advanced mode.

    ok, a wyswyg edition to shift the curves...


    Quote Originally Posted by Bill Burk View Post
    Draw the ASA triangle. Show the selected points for contrast measures and support Kodak Contrast Index as well as other gamma, average gradient measures. Show a Time/CI curve.
    Quote Originally Posted by Bill Burk View Post
    As well as support the Zone System N’s
    Ok... good ideas.


    Quote Originally Posted by Bill Burk View Post
    Import manufacturer’s data sheets and overlay expected vs actual results.
    What would be easy is importing an image (sceenshot), to be scaled and placed under the graph, ok.



    Thanks for te ideas pointing where development should target.

  3. #13

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    Re: New darkroom calibration software.

    Quote Originally Posted by Jac@stafford.net View Post
    What ever happened to test strips or personal experience?
    It's the same old belief/ delusion that has persisted for many, many decades that art in photography can be reductively turned into a form of applied maths that will hence produce a 'perfect' print. Which while it is fine (great, even) for industrial printmaking, it just doesn't understand the way that making a great print is about far more than sensitometric calculations.

    Fundamentally, it's a worldview that denies the acquisition of aesthetic skill (art) & knowledge (science) & the practice thereof in favour of a techno-fetishistic belief that with all this software, gubbins etc you too can become a great printmaker...

  4. #14

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    Re: New darkroom calibration software.

    Quote Originally Posted by interneg View Post
    Which while it is fine (great, even) for industrial printmaking, it just doesn't understand the way that making a great print is about far more than sensitometric calculations.
    Interneg, this is not the aim of this software. Since several years ago I'm addicted to Sally Mann and Denise Ross ways.

    I'm thinking in this tool as a way to assist those (me the first) wanting learn advanced techniques and to also be useful to speed up boring technical tasks.

    The last thing I want is being intrusive in the optical path. I'm a radical beliver in the purity of the optical crafting.

    There is something that I don't like: positive discrimination for the optical process. To me it's wrong to give a higher value to an optical work because "it's more difficult". What need a positive discrimination are digital works, IMHO.

    ...but optical crafting of a print can be exhausting when a situation is complex.

    I don't plan making great prints from great sensitometric calculations, at all. What I plan is making sensitometry easy, to reach the good point easier, faster and by wasting 1/4 of the paper.

    What the print has to be it's in the photographer's mind. This tool it's not about the photographer's mind. This tool will be about making easier to craft in a print what's in the photograper's mind.

    I hope that if you follow the evolution of the development then you may find that this is the intention.

  5. #15

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    Re: New darkroom calibration software.

    I am not sure what you plan to do with all this sensitometric data to help you print a negative. Is it to select paper grade?

  6. #16

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    Re: New darkroom calibration software.

    Quote Originally Posted by faberryman View Post
    I am not sure what you plan to do with all this sensitometric data to help you print a negative. Is it to select paper grade?
    Yes, we can load:

    > a negative, calibrated with the stouffer, we know densities
    > a film calibration, with several curves
    > a mask (crm/scim) that is obtained from the negative + particular curve of the film calibration + exposure setting
    > we also have the negative + mask sandwich like if it was a new negative
    > a paper calibration, with different grades, a particular calibration is for grades from a color contrast masking of the Alan Ross process
    > a color contrast mask, Alan Ross type
    > a preflash layer

    This is to make a proofing of how the print of a negative will be with a particular BW masking + Color masking + paper curve.

    I don't plan that the result has to be exact, just it will show the path we should follow, allowing for example to know how to expose an scim mask to have more or less the effect we want, delegating in the manual crafting the refined adjustments.

    BTW it plots fim/paper calibrations, and tells how to expose/process BW slides.

    Most of the structural work is done, user interface development is slow and boring. In some two months it may be ready for testing, if someone wants.

    For the moment you scan a calibration alongside the stouffer and it delivers data to Excel to plot the film curves, and works like a densitometer if scanning a negative with the stoffer. This weekend paper calibrations will be up. A paper calibration has 2 wedges, one is the trasmission one to say the exposure each step on paper received, and an additional reflective wedge scanned alongside the paper strips calibrates the resulting densities in the steps.

  7. #17
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    Re: New darkroom calibration software.

    Take my money!

    (especially if it's freeware) I like the idea of this replacing a densitometer. People derided phones being replacement for incident meters and it has happened for many people. Using what people have is appealing compared to getting extra instruments.

    The film testing part I mostly interested in testing different development and this would quantify those differences with very little work on the end users' part.

    Sounds like #5 could be useful to quantify the effect of pyro stains.

    From the screenshots, it seems like someone could run it on linux with wine if needed. I use Linux for work and surfing but it's not as practical for photo editing and scanning where Windows/Mac are the more versatile tools.

  8. #18

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    Re: New darkroom calibration software.

    The densitometer works perfectly yet, you only need an stouffer or similar. If you want to test yet it just PM.

  9. #19

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    Re: New darkroom calibration software.

    Quote Originally Posted by faberryman View Post
    I am not sure what you plan to do with all this sensitometric data to help you print a negative. Is it to select paper grade?
    It’s to help you evaluate whether or not you are getting the quality you want from your negatives.

    And if not, what direction and how much to change development and/or exposure...to make them better next time.

  10. #20

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    Re: New darkroom calibration software.

    Quote Originally Posted by Bill Burk View Post
    It’s to help you evaluate whether or not you are getting the quality you want from your negatives.

    And if not, what direction and how much to change development and/or exposure...to make them better next time.
    Bill, yes, these are the primary objectives, helping to be aware about how we are using the medium, and helping to get a solid criterion about what to do to refine our process, so we would spare energy to focus in on the subject or on the print aesthetics, of course one may not need that help from a software... anyway if wanting curves for something it does it with a few clicks and no densitometer

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