Determing the Correct Development Time

Discussion in 'Darkroom Developing and Printing' started by rgans, Nov 15, 2004.

  1. rgans

    rgans Guest

    (I asked a question about using Photoshop to determine the correct dev.
    time...this is another question):

    If I have two negs, one shot at 1 sec at f/22 (the metered speed) and the
    other at 1/15 at f/22, the first one should be at Zone V and the second at
    Zone I (correct?).

    If so, after development, if I meter a gray card (using the Pentax Digital
    spotmeter) and get, say, a reading of 5 and one dot. Is there a way I can
    meter the negs for a comparison? If this is possible, what should I place
    the negs over to meter? White paper? A gray card? What?

    THANKS!!!

    RON
    _________________________________________________________________
    B&W Landscape and Still Photography: http://www.ronaldgansphotography.com
     
    rgans, Nov 15, 2004
    #1
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  2. rgans

    Frank Pittel Guest

    I always determined film speed by making zone I exposures at different film
    speeds and a densitometer. I then determined development time by exposing at
    zone VIII at the proper film speed and after determining a "standard print time"
    The amount of print time required to get maximum black through a developed but
    unexposed negative, printing for that time and determining which development time
    gave me a proper "zone VIII" print.


    : (I asked a question about using Photoshop to determine the correct dev.
    : time...this is another question):

    : If I have two negs, one shot at 1 sec at f/22 (the metered speed) and the
    : other at 1/15 at f/22, the first one should be at Zone V and the second at
    : Zone I (correct?).

    : If so, after development, if I meter a gray card (using the Pentax Digital
    : spotmeter) and get, say, a reading of 5 and one dot. Is there a way I can
    : meter the negs for a comparison? If this is possible, what should I place
    : the negs over to meter? White paper? A gray card? What?

    : THANKS!!!

    : RON
    : _________________________________________________________________
    : B&W Landscape and Still Photography: http://www.ronaldgansphotography.com



    --




    Keep working millions on welfare depend on you
     
    Frank Pittel, Nov 15, 2004
    #2
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  3. Correct if your meter is accurate and your shutter is accurate.
    Rather difficult and the accuracy is questionable, however in theory and general
    practice you can do it by placing the two negatives on a light table of even
    brillance or by placing the negatives over the spot meter and shining the enlarger
    light through the negative. A densitometer/or analyzer is the best way to establish
    accurate results. You could also print both negatives using the same exact enlarger
    exposure, paper development time and visually determine the difference. You would
    have to determine first black on the photo paper before hand
    because the Z1 neg is going to print all black.
     
    Gregory W Blank, Nov 15, 2004
    #3
  4. I am assuming you were photographing a gray card or something
    similar.
    Each zone in the zone system is one stop apart. The difference
    between 1 second and 1/15th is about 4 stops (1/16th to be exact) so
    the two should be 4 zones apart. This assumes no reciprocity effect.
    The zones of the zone system are related to printing paper density,
    running from paper white to paper maximum black. The density range of
    a reflection print is somewhere around log 1.5 to log 2.0. This bears
    no direct relationship to the densities on the negative because
    nothing is said about the contrast grade of the paper. The paper
    contrast relates the contrast, or density range, of the negative to
    the density range of the paper. The higher the paper contrast the
    shorter the density range on the negative that is needed to produce
    the full range of densities on the paper.
    Development controls negative contrast. In this way negagives vary
    from prints. Prints are nearly always developed to the maximum
    contrast the material is capable of. Film for pictorial puposes is
    developed to a much lower contrast than the maximum. The idea is to
    match the contrast of the negative to the contrast of the paper. The
    Zone System was designed to help photographers make negatives which
    would print with good tonal rendition. The idea is to fit the scene
    contrast onto the film so that the desired range of tones will print
    on _normal_ grade paper. Since varying development also varies the
    minimum and maximum densities of the film it is desirable to expose
    the film so that it is neither too low in density for the shadows to
    have good detail or so great in density that it requires long printing
    exposure times.
    I think one reason for choosing to vary the negative contrast
    rather than matching by paper grade was that the curve shapes of the
    different paper grades did not always match so the tone rendition was
    not always the same for a lower contrast negative printed on higher
    contrast paper and a higher contrast negative printed on lower
    contrast paper even though both negatives were exposed correctly. Some
    graded papers are better than others in this respect, but there are
    few graded papers on the market today. For variable contrast paper
    there may still be an advantage to controlling negative contrast
    because some VC papers do not vary highlight contrast much from grade
    to grade.
    I am rather of the opinion that more conventional senstometric
    methods may be less confusing than the zone system but they are really
    just different approaches to the same end: getting consistent and
    predictable tone rendition on prints.
    Most B&W negative materials will produce good tonal rendition over
    a wide range of increased exposure once a certain minimum exposure is
    given. The main advantage of keeping exposure to a minimum consistent
    with good shadow detail is that thinner negatives tend to be less
    grainy and sharper than denser ones. This makes much more difference
    for small negatives than for large format ones.
    Now, after all this exposition I am still not sure I am even
    addressing your question, my excuse being I have been awake too many
    hours.

    Richard Knoppow
    Los Angeles, CA, USA
     
    Richard Knoppow, Nov 15, 2004
    #4
  5. What are you talking about?
     
    Uranium Committee, Nov 15, 2004
    #5
  6. rgans

    jjs Guest

    Be nice. He's not only got Zonsystitis, he's got Photoshop!
     
    jjs, Nov 15, 2004
    #6
  7. To Ron,

    1. Run a test roll, (or several sheets) of a smooth blank surface, e.g.
    a wall. Meter for Zone V, and then stop down four stops (less exposure)
    for Zone I. Make five or six exposures, bracketing 1/2 stop each time
    (e.g. 3 half-stops above and 3 below the Zone I reading). Leave a frame
    or two unexposed. Keep the shutter speed the same if possible and vary
    the f/stop to bracket. Record your exposures. Develop at some time
    that's going to be "in the ballpark," i.e. the manufacturer's suggested
    time.

    2. Since development time does not affect the lower zones as much as
    the higher ones, as long as you're not a mile off, you're OK. Then, on
    an evenly illuminated section of a lightbox (mask a spot the size of
    your neg with a card or tape), take a piece of the developed film from
    an unexposed frame. Place this on the masked area of the lightbox, lay
    on top of it a .10 Wratten neutral density filter. Then put your
    digital spot meter on the film/filter sandwich and make a reading. This
    is your Film base/fog plus .1 density reading. Write it on the piece of
    blank film.

    3. Next, place each exposed negative in turn over the masked area of
    the lightbox and meter it with your spot meter. Record the reading for
    each. When you find the one that is the same as your Fbf plus .1
    reading above, note the f/stop you recorded for that exposure. This
    will tell you your true film speed for that film and that camera shutter.

    4. Determine minimum exposure time (under the enlarger) for maximum
    black. Three-second increment exposures on a test strip with a piece of
    the unexposed clear film in your carrier. Let's say you get a maximum
    black in 8 seconds at f.11 with your enlarger at the height you'd use
    for making contacts. Mark the enlarger column so you'll know where the
    head was positioned.

    4. Now expose another roll (several sheets) at that film speed, of the
    same wall, but this time, opening up three stops to place the exposure
    on Zone VIII. Expose all frames at the same exposure. If roll film,
    cut off 1/3 of the roll (or one of the sheets) in the dark, and develop
    it for the manufacturer's suggested time. When finished, make a print
    of one of the frames at the exposure time for maximum black that you
    previously determined. If there is more than a very slight tone and
    texture to the print, you've overdeveloped. If there is no tone or
    texture at all, you've underdeveloped. Repeat using another 1/3 of your
    test roll, this time, developing for 20% less or 20% more, whichever is
    appropriate. Make another print at the exposure time for maximum
    black. You should be right on or very close. If necessary repeat with
    the last 1/3 roll (or third sheet) and tweak the development time again
    in whichever direction is appropriate. By now, you'll have your Zone
    VIII exposure time for that film, paper, developer combination.

    This was essentially Fred Picker's film speed/development time testing
    method. It's always worked well for me. The difference is he
    recommended a densitometer, and I couldn't afford one, so I improvised
    with my spot meter and a Wratten filter, and it worked well.

    Larry
     
    LR Kalajainen, Nov 15, 2004
    #7
  8. rgans

    rgans Guest

    I don't think you actually answered my question, but, as usual, I totally
    enjoyed reading your reply and, as usual, learned a lot from it...so
    THANKS!!!<G>.
     
    rgans, Nov 15, 2004
    #8
  9. rgans

    rgans Guest

    Thanks. That helps me tremendously!!!
     
    rgans, Nov 15, 2004
    #9
  10. rgans

    Frank Pittel Guest

    : : > message : >> (I asked a question about using Photoshop to determine the correct dev.
    : >> time...this is another question):
    : >>
    : >> If I have two negs, one shot at 1 sec at f/22 (the metered speed) and the
    : >> other at 1/15 at f/22, the first one should be at Zone V and the second
    : >> at
    : >> Zone I (correct?).
    : >
    : > What are you talking about?

    : Be nice. He's not only got Zonsystitis, he's got Photoshop!

    Ignore!!

    --




    Keep working millions on welfare depend on you
     
    Frank Pittel, Nov 16, 2004
    #10
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