Determining contrast grade in the darkroom

Discussion in 'Enlarging' started by Marc Leest, Feb 1, 2004.

  1. Marc Leest

    Marc Leest Member

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    I waste a lot of proof prints to find the correct contrast grade. Mostly I will find a satisfactory grade to print on, but I think my technique is not good enough.
    Wat is the best method ? Contactprints ? Proofprints ? Densitometer ? Darkroom lightmeter ?
    -Any tips are welcome.
     
  2. DrPhil

    DrPhil Member

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    test strips are used by many. I know some people that us e a full sheet and expose it in quarters. Each quarter is at a different grade. I have an analyser pro which works as a light meter. With it you can previsualise the final result. However, it takes a while to calibrate the thing. I highly suggest a stouffer transmission step wedge to calibrate the analyser pro. I use a reflection densitometer to set the final results on the paper up.
     
  3. Ole

    Ole Moderator Staff Member Moderator

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    A densitometer is surely a good help. I use my Ilford EM-10 darkroom lightmeter with good results: I took one negative with a very long range, printed it on the full range of Ilford MG IV RC. I then measured points on the negative giving almost full black, almost white, and medium grey for all prints. I can then read key values on any negative and adjust aperture/filtration to fit. Note that my MF enlarger is an Opemus with four filter wheels: C, M, Y and N(neutral) so that I can tune the illumination to print anything at 10s base exposure.

    But this is only useful when there's an absolute minimum of burning and dodging to do. Mostly I just look at the projected image to determine what grade is likly to give a good image, then use the meter to indicate how much burning to do to get the values I want...
     
  4. dr bob

    dr bob Member

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    Densitometers work and may be of benefit in many ways. However in my dark-age darkroom, I rip up a sheet of whatever and use a piece approximately a quarter of a full-sized sheet, and place it in a critical part of the image. Usually it requires no more than a couple of trials to acquire the necessary data (by inspection) to home in on the required contrast grade and exposure for a test/working print.
    Caveat: it requires a lot of paper to arrive at most of the fine images you see, here and elsewhere. So be patient and expect to use some paper.
     
  5. Les McLean

    Les McLean Subscriber

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    I agree with dr bob, there is no repacement for knowledge of technique to support your own judgement. Initially, you will spend a lot of time and use a lot of paper in learning how to put on to paper the tonality and contrast you see as being the most expressive for the image you are printing. Once you know the darkroom dodges you will find that the only thing you cannot do is put detail into a shadow when it has not been given sufficient exposure at the taking stage.
     
  6. jobel60

    jobel60 Member

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    Just a quick thought on the grading problem. I always start at a grade 3 - using RC VC paper - and do a test strip about 2 inches wide. This gives me a good indication of the exposure times and if the grade is to high/low. Sometimes I will choose a grade, do a basic print, then do a grade higher/lower as the wont takes me. It might seem hit and miss but after dry down etc you will be surprised at how you may have misjudged the grade in the first place. Plus it's good experience to look at a print in different grades because after a while you instinctively guess the right one and get it right.
     
  7. CPorter

    CPorter Member

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    I agree with Dr. Bob as well, learn to use your eye and just think of all the money you will save on gadgetry. Not that accumulating equipment is all that bad. I can't think of one reason why I need to purchase expensive equipment to judge the contrast of my test strips/staight prints. The key, I think, is to be patient and view your prints in white light after dry down.

    After I have determined my basic exposure for the most critical area of the print (not a step test across the image), I then expose one strip at that basic exposure at each hole grade contrast number. I already know the extremes will be there at each end of the contrast test, but I find it useful to view those extremes for local contrast controls in mult-grade printing. After I have determined the best contrast for the critical area, I make a straight print with the basic exposure at the chosen contrast grade. Often I will make several straight prints at the basic exposure using whole grades and then half grades. Once I'm happy with an overall contrast, I start to think about dodging and burning needs. I didn't mean for this reply to get so "wordy".

    Good Luck
     
  8. kkranis

    kkranis Member

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    I normally use the test strip method, but start with 2 - 2.5 grade.

    Grade3 is a bit on the edge (more contrast and after that, the exposure times change...
     
  9. L Gebhardt

    L Gebhardt Subscriber

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    I use a Multigrade head and VC paper. I try and find the correct time for the highlights in the print at grade 2 or 2.5 and make a print. I then look at the print and decide if if needs more or less contrast. I then make another print at the new contrast. The Multigrade head is nice because the exposure times really do not move much as you change grades. My method wastes some paper, but it works very well.
     
  10. DrPhil

    DrPhil Member

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    Some details on my method

    Even with my analyzer pro I still use several test strips. I have an odd method; however, it seems to work for me.

    I first look at the print on the easel and decide if anywhere is going to need burning in. This is where the analyzer pro is really handy. I can measure if a certain area will need 1 stop 2 stop etc.

    I then decide where the highlights will be with my base exposure. The analyser pro will often give me a starting point; however, I usually expose three or four pieces of paper to get the highlights right. To do this, I tear up a sheet of paper into small pieces and position them where needed in the print. I use the f stop function on my timer to print each piece above and or below the starting point suggested by the Analyser pro. On each piece I write the time and develop them all together.

    Once I've decided upon my highlight time, I print a full sheet at grade two to start working on the correct contrast grade. This is where having a calibrated system is really great. I spent a weekend once figuring out the contrast grades for my dichroic head. Now all of my settings are the same density. Thus, my highlights stay the same when I change grades. From the grade two print I decide if I need more or less contrast. Once this is decided, I return to dodging and burning.

    For dodging and burning I again print on small pieces of paper. The Analyser is often hand to get a starting point; however, I print several pieces, write the exposure info on the back, and develop all of them. Often, I will take all of the pieces and lay them on top of my working print. As I sit around with a cup of coffee, I decide how much burning/dodging that I like. Once I've decided which parts I like the best, I create a burning dodging plan. Often though, I return to the darkroom and make many more little pieces of areas at different grades. The end result is a base exposure and burning/dodging plan that covers several grades.

    My method uses alot of paper; however, having a calibrated system saves paper in the long run. I have two densitometers, f-stop timer, Analyser, and more; however, the method that produces the best reults is lots of little test prints. I think that my results improved the most when I started sitting down with the puzzle pieces and building the picture.
     
  11. Donald Miller

    Donald Miller Member

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    My printing until recently amounted to what others have indicated.

    More recently, however, I have taken to printing at a contrast grade 1/2 to 1 grade higher then what the negative would normally be printed. I then do a test strip that provides me the shadow tonal values that I want and preflash the paper to compress the overall contrast range. This provides greater local contrast in the print and makes the print "glow".

    The alternative to this is to prepare shadow value masks from lith film. In that method, I do a test strip to determine my highlight tonal scale then I mask the negative in the first exposure to hold shadow values back and then burn them down to the appropriate value in a second exposure using the second mask of the set.

    Both methods work to provide greater local contrast while compressing overall contrast. Which is better? That depends on the subject matter and the presentation that the photographer wants. Sometimes a print needs greater highlight separation at the loss of some of the shadow separation and sometimes a print needs greater shadow separation at the loss of some highlight separation. The use of these two methods will allow the photographer the choice of which presentation to use.

    There is no doubt that these methods will give greater print vibrancy due to greater local contrast.
     
  12. Juraj Kovacik

    Juraj Kovacik Member

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    I'm feel really uncertain at this point, becouse I've printed on MG papers only few tens' of prints. The amount of possibilities you can choose from it is enermous. I afraid it would take some time and lot of bad prints to take sense for what filter could be the best for that or another print... Yesterday I printed first time with 0 filter and was amazed how rich gray scale it can produce...

    Gennerally I think question of contrast is - in some and sometimes relatively wide range - question of taste and there is nothing as "the best solution", or not "the best solution for everybody". But that is maybe more about my current uncertainty then about the facts... jk
     
  13. John McCallum

    John McCallum Member

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    Hello - I'm new to this forum (about 10mins old) but I read this question with a bit of interest since it's a prblem I've had recently as well. I have been trying a method of assessing correct contrast which seems to work very well on many of my negs. It goes ...
    First print for the highlights on a very low grade contrast filter (1 or less). Ignore all shadows (I know it's hard to do). When you have the correct print exposure/paper combination to give the highlights you want in the final print, then look at the shadows. Are they clean with good density, or 'muddy'? If muddy, then try a higher contrast filter. Check the shadows again - clean/dense or muddy. Keep going until you have the look in the shadows that you want without too much loss of detail there.
    Only rule - never change exposure time and filter at the same time (the old don't change two variables at once rule) it will throw all your hard work out the window! and practice (until the Zen thinking takes over!!!) :?
     
  14. Ross Chambers

    Ross Chambers Member

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    John McCallum's approach sounds very close to split grade printing, which I have recently found to be of great assistance in reaching a good starting point print 3 sheets into the process. John hasn't said that the second high contrast exposure is made as an incremental series of timings on top of the low contrast one, but this works for me.

    Ross (a member for 5 minutes!!)
     
  15. Rick Jones

    Rick Jones Member

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    Marc-I believe anyone interested in making the best possible print uses a lot of paper but I have never thought of it as wasting paper. It's just part of an inevitable process. For me the first step is determining the proper exposure for a key area in the print at a relatively low contrast (2 or 2 1/2 filter). Something that has been a great help to me is a test stripper which enables me to make six different exposures of the exact same area on the print. I then make an unmanipulated work print and start the process of considering how to make improvements with burning ( seldom use dodging) and changes in contrast. Maybe I too waste a lot of paper but it sure is fun!
     
  16. Tom Duffy

    Tom Duffy Member

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    I think you'll find a good range of techniques used by the folks on APUG. Some use densitometers, and are devotees of the Phil Davis BTZS system, which certainly makes sense if you're printing platinum, with its very high material costs. Others develop by inspection and print until it looks right. The densitometer approach is probably the most accurate, but seems like a huge learning curve when the "experiential" approaches will probably get you close enough.
    For a normal negative, I usually print one picture at grade 2 and another at grade 3. Once I pick the appropriate contrast grade (even with VC paper), I then do my fine tuning from there.
    The way I get burned, even to this day, is with print drydown. I end up printing several variations and picking the print I like after they dry. Not very professional.
    Take care,
    Tom
     
  17. mobtown_4x5

    mobtown_4x5 Member

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    My method?...

    Anyone want to buy about 1000 pounds of exposed, soggy, partially fixed VCFB?

    :smile:
     
  18. victor

    victor Member

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    in my practice there is split print. u can do everything with it. simply everything. read more about the split method, and with time it will be the best thing and the most creative and rewarding.
    about the test strips - with all the respect to the all analyzers (which are a great tools mostly), i think there is no substitution to test strips. there u can see really how the things look like and how u would prefer them. what analyzer can do, i can do it intuitivly. yes, not so scientifically acuratly - but i dont really want to print scientifically. i want to see, to sense, to have the vissual dialog with the test papers.
     
  19. Ka

    Ka Member

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    I have been advised to try split printing, at first 2 filter followed by 5 filter. How does one know when to stop the #2 and go to the #5? Or which ever filter grade preferable?
     
  20. c6h6o3

    c6h6o3 Member

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    I start with grade 2 and an educated guess as to the proper exposure. I always use a metronome when printing. After I've pinned down the highlights, I judge contrast and then make the decision which way to adjust it and by how much. I use Michael Smith's "outflanking" approach in tweaking all variables, which not only tells me the optimal overall exposure quickly but gives me most of the dodging and burning information along the way. This technique enables me to arrive at the print I want using the fewest sheets of paper, almost never more than 5. Furthermore, once I have the times down for a given negative, the prints are repeatably identical no matter how many I'm printing. This method applies to enlargements as well as contact prints, and on any paper no matter what I develop it in.
     
  21. Julia819

    Julia819 Member

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    I usually take a good look at the negative in light before I print and make an educated guess as to what f-stop and filter to start at. Assuming it's a good negative, I start at a 2.5 (I like my prints a little contrasty) and then make tweeks in time, etc. If I'm pretty confident in my exposure, then I make a test print with a couple different times to get my exact exposure. It works pretty well for me.

    Julia