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  1. #1
    BWGirl's Avatar
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    Making enlargements - how long & how do I know?

    I just got my photo from a fellow APUGer as part of the recent negative exchange. He sent a very detailed explanation of what he did when he made the enlargement (for which I am extremely grateful). But it got me to thinking (a dangerous activity at best)...

    What determines how long you expose a negative for when making a print? Does fiber-based paper need a longer exposure than RC?? How do you know when you should maybe open the lens up a stop and reduce the time of the exposure?

    This was a great exercise! I hope my 'print partner' will not be worried now that he knows I'm full of all these questions! haha

    Jeanette
    Jeanette
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    Isaiah 25:1

  2. #2

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    Jeanette,

    Thanks for posting this because I now understand your question. The exposure time is determined by the length of time that is necessary to give the desired tonal representation in the highlight areas of the print.

    This is typically done with a test strip with increments of increasing exposure. I place a strip of paper that I have cut down across the projected image on the easel. I then give increments of exposure by exposing the paper while incrementally uncovering portions of the unexposed paper strip.

    The shadow areas are controlled by the contrast filtration or paper grade that one uses. If the shadows are weak the filtration is increased or the paper grade (in the case of graded paper) is increased. If the shadows are too dark and lacking in detail then the filtration and or paper grade is decreased.

    Insofar as adjusting enlarger lens aperture...I try to hold my exposure time to no more then 25-40 second time and no shorter then 12 seconds. This is to provide time to burn and dodge the print in whatever way is required. I have at times had negatives that required longer times and I have at times had exposure times below 12 seconds when no burning or dodging is required.

    Re fiber and RC paper exposure times...someone else will need to answer that since I haven't used RC paper in over twenty years.

    Hope that this answers your question.

    Quote Originally Posted by BWGirl
    I just got my photo from a fellow APUGer as part of the recent negative exchange. He sent a very detailed explanation of what he did when he made the enlargement (for which I am extremely grateful). But it got me to thinking (a dangerous activity at best)...

    What determines how long you expose a negative for when making a print? Does fiber-based paper need a longer exposure than RC?? How do you know when you should maybe open the lens up a stop and reduce the time of the exposure?

    This was a great exercise! I hope my 'print partner' will not be worried now that he knows I'm full of all these questions! haha

    Jeanette

  3. #3

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    Jeanette,

    The short answer is that it's determined empirically, i.e., by trial and error. Exposure is usually dictated by the high values of the print. Low print values (shadows or dark areas) usually are set by choice of contrast grade (either the paper grade or, in variable contrast printing, the printing filter). Most people make a test strip on which successive exposures are incrementally longer (darker). There are other methods.

    Your best bet would be to start with a good book on the subject of printing, of which there are many. I've heard good things from knowledgeable folks about The Ansel Adams Guide : Basic Techniques of Photography - Book 1 by John P. Schaefer, but haven't seen it myself. Most any edition of the original Ansel Adams series would be good for basics and should be at your public library. Personally I like Way Beyond Monochrome by Lambrecht and Woodhouse, but it may be a little technical if you're just getting started. Others will have good suggestions, I'm sure.

    -Will
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    Anyone can appreciate a fine print. But it takes a real photographer to appreciate a fine negative.

  4. #4

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    Don's post was seconds before mine. Sniped again!

    -Will
    My Verito page

    Anyone can appreciate a fine print. But it takes a real photographer to appreciate a fine negative.

  5. #5

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    That is one of the few benefits of a life misspent on Ebay...my kids are becoming resentful at not having an inheritance to look forward to.

    Quote Originally Posted by wfwhitaker
    Don's post was seconds before mine. Sniped again!

    -Will

  6. #6
    VoidoidRamone's Avatar
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    Here's basically what I do to determine exposure... after getting the negative focused, etc. Cut a piece of photo paper in strips, I'd go with strips approx. 2"x8", so you can get 5 strips per 8x10 sheet. Then place a strip on the easel and get a piece of opaque matboard or something of that sort. Set your timer for about 3 seconds, cover all but about 1-2" of the strip with the matboard and expose the paper... then repeat until the entire strip has been exposed, moving the mat board 1-2" each time and exposing for about 3 sec each time (remember to keep it constant for each strip)... then develop the strip, and look at which area is the "correct exposure". If the whole strip is too light, do the same steps except expose the whole strip for something like 10 or 20 seconds before.

    Also I tend to make my first prints (work prints) with a relatively low grade of contrast and move up from there... I'm not sure about the difference of exposures for FB and RC, but I do know that you can get higher contrast on FB if you use a larger aperture... this is not as drastic an effect with RC. Also remember to account for drying down with FB, when FB paper dries it tends to be about 10% darker. Also, like Donald, I try to keep my exposures around 30 seconds, for dodging and burning.

    Hope this all helps, good luck. -Grant

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    Jeannette,

    Donald covered most of your question perfectly, like he always does. Here is what I know about RC vs Fiber, with Ilford MGVI my times do not change when everything else is the same. I use the same exposure for fiber that I use for RC (have been using up my stock of RC for test prints). Now, if you change paper, say from MGIV to MGWT that is a different story, my experience with MGWT is it is a much slower paper. The first time I noticed this, I posted a question too! All I really had to do was read the package insert that came with the paper.
    That said not all of the paper I have tried recently has had a package insert - but most info is available via a web site.

    Good luck...BTW Donald, Thanks for reminding me I need to start cutting up my paper into strips for these test - cuts down on the waste, plus saves paper and money.
    Mike C

    Rambles

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    yes, the info sheet that comes with the paper usually has a speed rating, usually by filter value (drop in filters, not colour head settings). In theory if the numbers are the same, you should be able to expose the same for RC and FB versions, however I think it's a guide only, as I've found them not to be directly equivalent, I think it's probably a number of factors, the paper itself, how it reacts to the developer and the dry down affect.

  9. #9

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    Quote Originally Posted by Nige
    yes, the info sheet that comes with the paper usually has a speed rating, usually by filter value (drop in filters, not colour head settings). In theory if the numbers are the same, you should be able to expose the same for RC and FB versions, however I think it's a guide only, as I've found them not to be directly equivalent, I think it's probably a number of factors, the paper itself, how it reacts to the developer and the dry down affect.
    Nige, you are correct of course - as with most of what we do, it is a guide only. Light source, filters (and age of filters), plus our own darkroom habits can be a factor.
    Mike C

    Rambles

  10. #10
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    Jeanette, there is another way of exposing, but the rest has been well covered by previous posts. If you decide that a 20 second exposure (just to pick a number) is about what you feel comfortable working with in an image, try setting your timer at 20 seconds and then vary the f-stop instead of the time. Assuming your setup is already correct with respect to focus, crop, etc, a change in stops will enable you to see the relationship in tones you need fairly quickly.

    If, for example, you have a portrait you are working with and know the values for highlights you want, work that area initially and get the exposure you need for that portion. If the rest of your technique is correct (film speed, exposure, development, lighting, etc.) the print will be very close and you will just have to do a bit of fine tuning to get it to work. This is just another method of doing a print, but you might give it a try.

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