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  1. #1
    Denis P.'s Avatar
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    Determining exposure for B&W?

    I need some help...
    I'm not an expert in printing, and usually use grade 2 paper for all of my prints
    In determining the "proper" exposure, I use test strips with the same section projected - i.e. I have a crude DIY test strip printer, in which I slide the test strip for each new exposure, exposing always the same part of the negative... But, it takes long, and I never get it right with the first strip.
    So, being inclined to use all kinds of gizmos, I thought about Ilford EM10 exposure meter, but it's not readily available where I live. Since I already have a color analyzer (Philips PCA 060), which I never used, since I don't do color, only B&W, I thought that perhaps this could be used to speed up the process of nailing the "correct" exposure for the straight print.
    Trouble is, I don't know how to use it. It has an on/off switch, and switches marked with yellow, red and blue dots, and dials marked "sec", and "Y", "M" and "C" - and, naturally, an analog scale ("balance") with zero in the middle and +/- scale going to 10 on each side.
    I know I'm supposed to get a "perfect print" and use it as a reference point - but how? Ignore the Y/M/C dials and use only seconds for "zeroing", or what?

    In short, I'd be more than grateful if anyone would be so kind to help me in this regard. I don't know if it's even practical - using a color analyzer to determine B&W print exposure on a fixed grade paper (grade 2). I suppose it would be useful for VC paper, but I don't use those...
    Is this idea practical at all?

    Thanks in advance,

    Denis

  2. #2
    rbarker's Avatar
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    Although it might be possible to use your Philips color analyzer in this manner, I suspect that it would take an excessive amount of testing with each paper type to arrive at something useful.

    As an alternative, I'd suggest looking at the darkroom exposure meters from RH Designs, located in the UK. I use their ZoneMaster II enlarging meter, and it's great. It stores curve parameters for several papers that can be called up as needed, and there are calibration procedures outlined for papers for which they don't have curve data. So, you can tailor it to whatever papers you commonly use. Their site (http://www.rhdesigns.co.uk) provides for online ordering.
    [COLOR=SlateGray]"You can't depend on your eyes if your imagination is out of focus." -Mark Twain[/COLOR]

    Ralph Barker
    Rio Rancho, NM

  3. #3
    Will S's Avatar
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    I'll second the RH Designs idea. I've got one and it has saved me innumerable test strips. Though you do have to recalibrate it for different paper types (with maybe the exception of Ilford Multigrade which it comes calibrated for already.) If you use VC paper it is a real treat to use. Just figure out the exposure and then adjust to the grade of contrast you want/need and put the filter in the enlarger (or dial it in, or whatever)

    good luck,

    Will
    "I am an anarchist." - HCB
    "I wanna be anarchist." - JR

  4. #4

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    My thoughts are that since you already have the color analyzer, I would begin by trying to find a way to utilize it rather then buying a new and possibly unneeded piece of equipment. Departing from that orientation, I will describe what I would do were I in your shoes.

    It should be possible to utilize your color analyzer as a printing aid for black and white. However it probably will require some calibration to arrive at a point determining proper exposure.

    What I would do is this. I would use the analog scale that you mentioned since the color channels (CYM) will typically be used to determine color balance in printing a color image. However every color analyzer that I have ever encountered must also have the ability to read density and the analog scale would seem to be involved with that function.

    What I would begin by doing is this. I would take a typical camera negative incorporating a fairly full density scale (white to black) and I would begin by making a test strip of an important highlight that I wanted to show some detail on the print. I would then take the probe of the analyzer and place it into the projection of that portion of the negative onto your enlarger baseboard/easel. I would zero the analog scale at that exposure. This should give you the value that will then repeat in subsequent exposures.

    Once the highlight print value is determined, the paper grade or filtration changes will determine the shadow placement.

    To recap... I would use the analyzer to determine the analog reading of the highlight value. I would then use paper grade or filtration changes (in the case of VC materials) to determine my shadow tonal placement.

    If this works, you will have saved money that you can spend in other more productive and hopefully satisfying ways. At any rate, you will not have spent any money to try.

  5. #5
    Bob Carnie's Avatar
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    Hi Denis

    Don"t take this as criticism,
    I think you are overcomplicating things. Actually you are making road blocks for yourself.
    There are numerous reference books on how to simply make a test strip , then change filtration and density , then make a simple print, make your evaluation and so on and so on.
    I think the computer in your brain will tell you when you have the perfect print.
    I do not use any analyzers for any of my work as Brett Weston apparently said about not using light meters (what happens if the damm thing breaks)

    Make your darkroom proceedure extremely simple, I still use a sheet of card to do my step offs.
    As well do not creep up on your changes, go beyond what you think the corrections should be and if you have gone to far back off a bit.
    This way you will learn what a 1/2stop change or 2 grade change looks like.
    Micheal A Smith wrote an excellent article years back on printing changes and I believe it is on his web site.
    Keep it simple

  6. #6

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    Hi Denis. I think you might have trouble getting that reference print you're after using your colour analyser. I agree with Ralph, it would take a lot of time and testing (and interpreting of the results you would be getting) to turn it into something useful.
    The RH Designs analyser or enlarger timer would be a good investment of you're serious about printing in the long term, and if you feel comfortable with the cost. I have the analyser, and it is excellent - can recommend it.
    To my mind, however, nothing beats getting your print right the manual way initially. Test strips will help obtain the correct highlight detail. Changing contrast, you are somewhat limited by using the one grade of paper, however Les McLean has some good methods of altering the contrast of graded paper. (It could be worth getting his book if you don't already have it.)
    ... and throw LOTS of paper at it!

  7. #7

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    With a enlarger purchase I received a Colorstar 2000 analyser which sounds like a similar beast (although no analogue aspect) to what you have. I didn't get a manual and couldn't locate one for a Colorstar 2000, just the more recent 3000 model (I have since found somone who'll photocopy their photocopied manual for me... waiting for it to turn up in the post any moment!). With some help from an APUG member who had one or had used one (can't remember which) I/we got it working for the purpose you mention.

    Here's what I did.

    1. Zeroed all enlarger filtration
    2. Made a print using normal test strip methods based on getting a highlight with just a tad of tone in it correct.
    3. Adjusted the colour settings on the analyser until it indicated neutral color balance (this might not do anything.. I just thought it a good idea as I'm printing with VC paper)
    4. Placed the sensor on the highlight and adjusted the analyser sensitivity until the time matched the test print.

    Now I can measure a highlight and be fairly confident the time will be somewhere around that I usually do this then do a test strip around that time in very small increments, eg if it says 6.4secs, I'll do a test strip of 4,5,6,7,8secs (Paterson Test Printer device). What I have found it's very good at is telling me what the time adjustment is for when changing the enlarger filtration. I place the sensor in a spot that gives me the same reading as the time I want (either from the test strip or a test print I've made) and change the filtration (typically adding some magenta in my case) and the time it shows seems pretty accurate.

    For me it hasn't replaced test strips (I think those and full size test prints are needed to see the balance of tones and composition as well as burning and dodging requirements anyway) but I've found it a useful darkroom device. Once I get the manual I might see if my setup method was anything like they suggest

  8. #8
    Denis P.'s Avatar
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    Thanks for the replies!
    I know I need more practice in order to get better at printing, and that no gizmo will be a substitute for that...
    However, I think some general indication of the exposure could be helpful. The ZoneMaster sounds very good, but also relatively expensive, so I think I might try the Ilford one and see if it can help. I'm sure it will be of help - if nothing else, it will be an aid in determining the change of exposure when changing enlargement.
    Off to ebay - unless someone here is willing to part with theirs

    Thanks,

    Denis

  9. #9

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    I haven't owned a EM10 but have played with one and I don't like them because they work from a set time and rely on you changing the lens aperture to get the right exposure unless there's another way to use them?. That's goes against my ideal of using the best aperture of the lens at all times.

  10. #10
    Bob F.'s Avatar
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    Quote Originally Posted by Denis P.
    ... However, I think some general indication of the exposure could be helpful. I'm sure it will be of help - if nothing else, it will be an aid in determining the change of exposure when changing enlargement. ...
    Denis
    There is always the temptation to think that some gizmo will make your life easier. It rarely happens quite as well as you expected. As Nige writes, you use the EM10 by changing the lens aperture and that is bad news as it will take you away from the sharpest aperture for your lens.

    For a given size enlargement, on the same paper, you will soon get a feel for the exposure time. For a properly exposed & developed negative it will usually be within a stop or so of some standard time. A test strip to test 6 or 8 exposure times around that time will get you to the best base exposure time. Cost: half a sheet of 8x10 paper. Even a badly exposed or developed negative will only require two test strips at most.

    Changes to exposure time with different size enlargements can either be calculated or read from a published graph in a darkroom book. As I don't often move from one size to another, I just use another test strip although I think the free software I use (leLab) has a built-in calculator - I never use it.

    It is possible that your use of only one grade of paper is not helping you get the hang of a typical printing exposure time: you may be overexposing the print in order to try and compensate for lack of contrast in the negative (and/or underexposing to obtain low contrast). You need to get used to different grades. You write that you do not use VC paper: unless you have a religious conviction against it, I think you aught to get some - it is soooooo much easier to learn with....

    With VC paper, you may want to look at split-grade printing as described in a recent thread here. I only started using this method last week and already I am finding it very intuitive for homing in on the correct print contrast after only a few darkroom sessions. Otherwise you are looking at the "expose for the highlights, grade for the shadows" method which requires experience and (for me at least) a lot more test strips...


    Good luck, Bob.

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