How to estimate exposure times?

Discussion in 'Enlarging' started by CHHAHH, Dec 26, 2013.

  1. CHHAHH

    CHHAHH Member

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    Hi!

    New to the forum and wow, this will be fun! So much information to read that will help me getting started! :smile:

    I would like to have a first, very very basic question that i am currently thinking about:

    How to you estimate the exposure time for enlarging?
    I mean, i will do a test stripe to find out what the perfect exposure time will be like...but how to you set the first time to start with?
    Or the time for contact prints?

    Maybe i am overthinking something here (or just being really stupid) but i seriously have no idea :smile:

    I am using Ilford Multigrade Paper...


    Thanks for your help! :D
     
  2. Sirius Glass

    Sirius Glass Subscriber

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    Welcome to APUG

    This is one way to get the time. http://www.freestylephoto.biz/41621-Delta-Projection-Print-Scale

    Another way is to have most of the paper covered by a card. Expose for 10 seconds, then move the card and expose for 10 seconds. Continue until the sheet is completely exposed. Ralph W. Lambrecht in his book describes how to do this by doubling the exposure time for each position. He is on APUG and the book is worth buying especially if you are just starting out.

    After a while you will know that with lens A set at aperture B and paper C it take D seconds, is the starting point.
     
  3. Tom1956

    Tom1956 Inactive

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    Yeah--a projection print scale pie-wedge doohickie gets you in the ballpark, and you go from there with test strips.
     
  4. Allen Friday

    Allen Friday Member

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    Do you use a consistent time for making contact (proof) prints of your negatives? If so, then you should be able to look at the contact sheet and know if the enlargement will print close to a standard time, need more time or less. After you have made a few enlargements from your negatives, you will know the base exposure time for each enlargement size. If a proof print of a 35mm negative looks good and it normally requires a 12 second exposure for enlargement, you know to do test stops with 12 seconds as the mid point.
     
  5. ataim

    ataim Member

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    Also a Ilford EM-10 will get you close. I shoot either 8x10 or 4x5 and will make an 8x10 enlargement of each shot. With the EM-10 I find my D-max point take a meter reading and set the enlarger to the pre-determined time and f-stop. 80% of the time I get a good enough idea on weather I want to mess with that print or not. I also have a pie wedge, But prefer the EM-10
    .
     
  6. cliveh

    cliveh Subscriber

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    10" X 8" at 2 stops down using a 2.8 lens, 6 seconds.
     
  7. Sirius Glass

    Sirius Glass Subscriber

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    How can you say that if you do not know the wattage of the enlarger bulb, whether he is using a condenser or a diffuser, which paper ...?
     
  8. cliveh

    cliveh Subscriber

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    He states he is using multigrade and I take it his bulb is standard to the enlarger. I am trying to give him a ball park time without confusing him with too much information.
     
  9. Christopher Walrath

    Christopher Walrath Subscriber

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    Yeah, you can guess half a dozen times or run a test strip or two and have an answer for sure. Even for contact prints.

    Oh, and welcome to the insanity.
     
  10. RalphLambrecht

    RalphLambrecht Subscriber

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    pure talent!
    my first 10,000 prints were way off.after that experience and economic need replaced the guesswork:wink:
     
  11. ic-racer

    ic-racer Member

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    Just guess any number for the first one. If it is too dark half the time. If too light double the time. I use little pieces about 2.5 x 2.5 cm. You can zero in on the correct time that way. As you get closer reduce your multiplier from 2 to 1.4 or 1.26. Just keep putting the new pieces in the same place on the projected image. I have done it like that for almost 30 years. The problem with the other type of test strip is that it shows different exposures for different parts of the image which is of not much benefit to me.
     
  12. Tom1956

    Tom1956 Inactive

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    To the OP...Lambrecht's material is what you want to be paying attention to. Search up some of it.
     
  13. Bill Burk

    Bill Burk Subscriber

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    CHHAHH,

    Welcome to APUG,

    I never know. I just make a test strip and if I don't see "too light" and "too dark" on that strip, I'll change something and try again.
     
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  15. CHHAHH

    CHHAHH Member

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    Hi guys!
    Thanks for all the nice answers. I guess i will just do test strips...
    If i won't change paper and enlarging size, the time should be stable at least for the contact prints, right?
    For each larger print i will then do a dedicated test stip...

    Btw: This community is huge! I spend hours reading stuff last night instead of sleeping :smile:
     
  16. pdeeh

    pdeeh Member

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    careful how much you read ... too much, and you could easily end up thinking photography and printing are impossibly complex activities requiring intensive research, sophisticated scientific knowledge and many pieces of expensive equipment ...
     
  17. RalphLambrecht

    RalphLambrecht Subscriber

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    test strips are your friend if you want it done right. no piece of expensiveelec tronic circuitrycan replace a good old test strip. I usually start with a 16stest strip +/-1stop in 1/3 stop increments,pick the one withe best highlightand do another one in 1/6 stop incrementsaround that.lastly do it again in 1/12 stop increments.3 sheets of 5x7"paper and I have the exposure nailed.:sad:
     
  18. Doremus Scudder

    Doremus Scudder Member

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    That's the basic idea.

    There are lots of refinements, gadgets and systems for determining print exposure, but you can, as I do, just take the low-tech and simple route. IMO it saves time and a lot of frustration.

    1: stop your enlarging lens down 2-3 stops from wide open.

    2: make a test strip. Start with a ten-second base exposure and then cover the strip in intervals. I like expanding intervals, so I use 2 seconds, 3 sec. 4 sec, 5 sec. etc. Your goal is to end up with a strip that has from approximately 10 to 30+ second strips on it.

    3: develop your test strip fully. Evaluate it. If you don't have a strip that is too light and too dark, you need to make a new test strip. Choose a different time sequence or change your lens aperture appropriately and use the same sequence you used before.

    4: repeat till you have a test strip with a too light and a too dark strip. Now, use the highlights as a guide to proper print exposure. Choose the highlight value you find correct and make a test print at that exposure.

    5: evaluate the print. If the contrast is not correct, change paper grades. This will change the print exposure time, so you need to make a new test strip at the new contrast grade.

    6: repeat the above till you get a print that has the approximate highlight and shadow values you want before beginning manipulations (dodging, burning etc.)

    Keep notes. That and experience will tell you next time what exposures you need for a test strip from a particular paper at a particular contrast grade.

    Best and good luck,

    Doremus
     
  19. tkamiya

    tkamiya Member

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    Here's what I did when I started out.

    10 seconds at whatever aperture and whatever size. Printed it, developed it, and looked at it. Too dark? Expose less. Too light? Expose more. It's actually that simple.

    In little while, you'll be able to guess a little better.

    If this is your very first time, I wouldn't worry about making good prints with least waste. You'll waste plenty no matter what you do....
     
  20. CHHAHH

    CHHAHH Member

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    Short update:

    I just did it! My first selfmade print last night! Was fun and i am feeling kind of addicted now. Yay!

    One thing puzzled me, and i think i am just not getting my head around the corner here: the test strip showed me, that a 4sec
    exposure time gave me rich blacks, nice highlights. I think it was f16.

    If i want to get a longer exposure time...let's say to do dodging and burning...i need to open the aperture more?
    Because at a camera you would close the aperture to get a longer exposure time. But with paper it works the opposite..
    Correct?!

    "Too dark? Expose less. Too light? Expose more"
     
  21. Rick A

    Rick A Subscriber

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    No, you need to stop down same as a camera. If you are already at f16, your negatives are thin, you need more exposure to the film, or more developing time, depending on results. Overall thin image but strong printing on film rebate means underexposed film. Weak image and weak printing on rebate caused by under development of film.
     
  22. baachitraka

    baachitraka Subscriber

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    Actually you have made one thing very clear by printing, that is how important is to make good negatives or how important is to give a proper exposure for the negative.

    Keep printing, you will end up fine tuning the entire system.
     
  23. Mark_S

    Mark_S Member

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    +1 Ralph's book 'Way Beyond Monochrome' will answer the question in great detail and give you everything that you need to get well exposed prints - but may be overkill when you are first starting out.

    What may be easiest is to set your aperture to something in the middle of the range of what your lens does (probably f8 or so), and then do a test strip where you double the amount of time for each section of the strip - cover 4/5 of your paper, expose for 30 seconds, then move the cover over so that only 3/5 of the paper is covered, and expose again for 16 seconds, move so that 2/5 is covered, expose for 8 seconds, move so that 1/5 is covered, and expose for 4 seconds, then expose the entire sheet for an additional 2 seconds. Now develop and you will have 5 sections with times of 2, 6, 14, 30, and 60 seconds. Hopefully one of those exposures looks close to being right and you can start fine tuning from there. If the exposure that looks right is at one end or the other of the strip, adjust the aperture on the lens - if the 60 second exposure is the one that looks best, open up by a stop or two, if the 2 second exposure looks good, close down. I usually like having exposure times which are on the order of 15-30 seconds, since this gives me time to burn and dodge, and is not overly long.
     
  24. bazzinga

    bazzinga Member

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    well, how i found my exposure. i did all test strip stuff'n'all, but as a beginner i had problems evaluating dry down and how picture will look in "regular" light. some pics that i loved after printing were too dark, some too light in "real life". but after some time i found out that when i place exposed paper in developer and picture starts to appear 17(+- sec) latter, i get result that i like next day. and it's constant, not depending of enlargement size.
    so i guess (actually i don't) it's just trial and error. find your way.

    //btw using only one developer (for now) -> Ilford Multigrade developer
     
  25. cliveh

    cliveh Subscriber

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    When making test strips, you may care to place a bit of photographic paper on the darkest, lightest and midtone of your negative projection.
     
  26. Konical

    Konical Subscriber

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    Good Evening,

    Allen Friday gives good advice. Be absolutely, fanatically consistent in making contact sheets. Before long, just a glance at the contact-sheet image will probably get you close to a good print exposure. In addition, write printing data on the back of your contact sheets; using that information for subsequent printing will, again, be very helpful. Obviously, a test strip is a good follow-up.

    Konical