test strips for large enlargements

Discussion in 'Darkroom Developing and Printing' started by John Bartley, Jan 7, 2005.

  1. John Bartley

    John Bartley Guest

    Again, wanting to do larger size prints, I need to tackle the idea of
    test strips for exposure. Having priced 16"x20" paper and keeping in
    mind that this is just a hobby for me, I'd like to reduce my cost as
    much as is reasonable without being a complete cheapskate. My idea is
    that if I buy 16"x20" (my target size) paper in the same brand and style
    as I am currently using in 8"x10", then I should be able to do the
    following sequence ::

    1) cut my 8"x10" into four 4"x5" parts

    2) set up my enlarger so that it is focussed and prepared including the
    having the 16"x20" easel ready to load with the final print sheet

    3) set a piece of the 4"x5" paper into a critical area of the print and
    hold it down with a temporary weight (doesn't have to be fancy)

    4) make my test strips on the 4"x5" pieces - hopefully, four pieces
    should be enough, so one 8"x10" sheet will suffice

    Then, having decided what my ideal exposures and aperture settings are,

    6) place the 16"x20" sheet into the easel and make what will hopefully
    be the final print

    My idea is that the papers should be almost identical and as long as the
    placement of the easel and the enlarger settings remain constant, then
    exposing a bigger or smaller piece for test purposes shouldn't make any

    Any thoughts?

    regards from ::

    John Bartley
    43 Norway Spruce Street
    Stittsville, Ontario
    Canada, K2S1P5

    ( If you slow down it takes longer
    - does that apply to life also?)
    John Bartley, Jan 7, 2005
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  2. John Bartley

    Ken Hart Guest

    There _might_ be variations from one size paper to another, even in the same
    brand/type/style. Then again, there might not in the paper that you buy! I
    would cut down the 16x20 sheet into test print sizes. Additionally, I would
    not go all the way down to 4x5 test prints for 16x20; I would use 5x8 or
    8x10 for test prints, depending on the subject neg.

    Ken Hart
    Ken Hart, Jan 7, 2005
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  3. John Bartley

    McLeod Guest

    I don't even bother to cut the paper, just rip it into strips.
    McLeod, Jan 7, 2005

  4. jan705 from Lloyd Erlick,

    Using sheets from a different package may be a problem.
    Unless it is from the same production batch, there
    could be small differences that result in small but
    significant exposure differences.

    I'd say it's better to sacrifice one of the sheets of
    larger paper to have test strips from the same
    material. This means it's best to buy paper in the
    largest size package possible, so the proportion of
    sheets used for test strips is relatively small. (It's
    also best from a unit cost perspective.)

    Lloyd Erlick Portraits, Toronto.
    voice: 416-686-0326
    net: www.heylloyd.com
    Lloyd Usenet-Erlick, Jan 7, 2005
  5. On Fri, 07 Jan 2005 06:02:43 -0600, McLeod


    jan705 from Lloyd Erlick,

    You must have proper humidity in your darkroom! If I
    did that without my trusty humidifier, I'd have specks
    on my prints. I'd advise doing all cutting or ripping
    of paper at a distance from the enlarger. In fact, I'd
    advise making the to-be-test-strips all at once, from
    one sheet, and storing them in a separate bag within
    the package of large sheets.

    Lloyd Erlick Portraits, Toronto.
    voice: 416-686-0326
    net: www.heylloyd.com
    Lloyd Usenet-Erlick, Jan 7, 2005
  6. This ought to work.

    What I generally do is this, I work with 8x10 paper to figure out the
    exposure, contrast, dodging/burning etc that I want to get the image
    that I want. I then use an Ilford EM-10, set it on the easel, in a
    place on the image with a mid-tone and turn the dial until you get a
    green light. Now move the enlarger head up and focus on the 16 x 20
    easel, then put the EM-10 on the same part of the image that was used
    for the 8 x 10, and open the lens aperture until the light goes green.
    Then do the same thing that you did with the 8x10 - cuts way down on
    the number of 16 x 20 sheets that you use before you get an image that
    you like.
    Mark in Maine, Jan 7, 2005
  7. John Bartley

    John Bartley Guest

    Thanks for the many great replies guys!!! It'll be a big help to me.
    Next I'll think a bit and stew on these thought of yours, then head out
    for paper etc.


    regards from ::

    John Bartley
    43 Norway Spruce Street
    Stittsville, Ontario
    Canada, K2S1P5

    ( If you slow down it takes longer
    - does that apply to life also?)
    John Bartley, Jan 7, 2005
  8. John Bartley

    jjs Guest

    news:%9mDd.62033$P%... [...]

    It is just plain better to cut up the 16x20" paper. Sure, you might find the
    lot (batch) number on the box and try to match it with some smaller paper,
    but I truly doubt you will find a match.

    When making very large prints for the first time, guestimating exposure for
    test strips can seem daunting. I suggest you use 'F-Stop' times to get the
    gross times.
    jjs, Jan 7, 2005
  9. John Bartley

    Art Reitsch Guest

    Here's another thought, the way I do it. I make an 8x10 workup print,
    doing all the burning and dodging, bleaching, etc. until I'm happy with
    the final product. With a little practice I don't waste much 8x10 paper
    doing this. Then I set up the 16x20 easel and frame the larger print in
    the same way, crank in the same filter setting, and finally open up the
    lens 1.5 stops (I had to test strip this a bit to get this setting but
    it remains the same from neg to neg). I often nail the 16x20 on the
    first try but rarely have more than one or two hit the bin until I get
    what I want. Of course, I use the same brand and style of paper in
    moving from the small to the large size.
    Art Reitsch, Jan 7, 2005
  10. That's what I do: I keep a paper package just for test strips, prepare a bunch
    at once (using my trusty paper trimmer) in various sizes. Then just reach in
    and grab the size piece I need.

    Today's bullshit job description:

    • Collaborate to produce operational procedures for the systems management
    of the production Information Technology infrastructure.

    - from an actual job listing on Craigslist (http://www.craigslist.org)
    David Nebenzahl, Jan 7, 2005
  11. John Bartley

    jjs Guest

    How can one have low humidity in a room with large open trays of liquid and
    running water?
    jjs, Jan 7, 2005
  12. John Bartley

    Jim Phelps Guest

    Proper ventilation. Behind my 190cm sink I have a duct running to a 125cm
    (5") variable speed exhaust fan to the outside. In this duct I have 8 vents
    about 5cm above the sink lip. Works great. I also have a hygro/thermometer
    mounted above the sink line to assure I keep a balance between bearable and
    too high/low humidity. Runs between 50 and 60% even during the summer.
    Right now (I just turned around and looked) it's at 55% - 21C.
    Jim Phelps, Jan 8, 2005

  13. jan805 from Lloyd Erlick,

    Where I live, a line of open trays would have very
    little effect. Even a humidifier next to the enlarger
    can't raise the whole room above fifty per cent
    relative humidity in the winter (dry season...).

    A device to give the darkroom worker a readout of
    relative humidity is invaluable.

    RC paper is a great way to judge the humidity - it will
    lie pretty close to flat under the enlarger at around
    50%. If the room is too dry the paper will curl visibly
    toward the photosensitive coating side. Too dry, and it
    arches around the other way. To watch it happen before
    your eyes, or at least nose, breathe gently on a corner
    of a sheet laid out on a flat surface like and easel or
    enlarger baseboard. This works best if the room is very
    dry, so the full 'travel' can be seen.

    Dry powder chemicals can absorb moisture, lenses and
    camera bodies and gear can develop fungus, stored
    finished prints can mildew, human mucous membranes hurt
    in excessive dryness -- all point to controlling (or at
    least monitoring) the relative humidity in one's

    Lloyd Erlick Portraits, Toronto.
    voice: 416-686-0326
    net: www.heylloyd.com
    Lloyd Usenet-Erlick, Jan 8, 2005

  14. jan1005 from Lloyd Erlick,

    In my earlier post, I made the above statement, which
    is incorrect.

    It should read as follows:

    If the room is too dry the paper will curl visibly
    toward the photosensitive coating side. Too humid, and
    it arches around the other way.

    There is a fortune waiting for the writer of the spell
    checker that knows what you mean ... (such as for
    instance, a spell checker might be suitable for Harry
    Potter and his girlfriend [girl friend? girl-friend?],
    whereas I would like a spelling checker ...).

    Lloyd Erlick Portraits, Toronto.
    voice: 416-686-0326
    net: www.heylloyd.com
    Lloyd Usenet-Erlick, Jan 10, 2005
  15. That's what happens here, until last night:

    This morning I took a set of FB prints off an Arkay flat-bed
    drier (started last night, set on low, 30 min timer, emulsion
    to the belt) and they came out image side convex. A lot
    convex. Never happened before and the humidity is low ...

    I'm going to soak them in Pakosol and try again.

    Chalk it up to general perversity.
    Nicholas O. Lindan, Jan 10, 2005
  16. Subject: test strips for large enlargements
    I set up exactly as you have described, but in addition, I have an 8X10 Jobo
    test printer* that has barn doors and makes four, 4X5 test prints on one piece
    of 8X10 and normally expose each sheet @ 5, 10, 15, and 20 sec. etc.

    After working out the basic exposure, I go on and work out the VC settings on
    subsequent pieces 8X10 paper.

    I then expose a whole sheet of 8X10 on what I have perceived as the most
    important part of the photo, then develop the 8X10 dry it and evaluate this
    photo in lighting similar to the lighting where it will be displayed.

    After it's all said and done I will go on and read the exposure with my EM-10
    and record the paper settings on the paper envelope or box for future

    Quite honestly, I normally use 3 or 4 sheets of 8X10's for each 16X20.


    Bob McCarthy

    *available new (60.00) or on Ebay at around $15-30.00 USD. Wish I had one in
    TheYankeeSnapper, Jan 10, 2005
  17. John Bartley

    Mike King Guest

    There will be variance in batch to batch both with process and with age.
    Better to test out of the same box. Sometimes a 2x16 is what you really

    I think one sacrificial sheet in a ten sheet pack or 2-3 in a 50 sounds
    about right. That's 10% or less, pretty good if you can keep your darkroom
    "sacrifices" to that ratio.
    Mike King, Jan 11, 2005
  18. John Bartley

    dplotusnotes Guest

    With test strips I'm more concerned about coverage than anything else.
    The goal of a test strip is, for me, to cover enough area to provide a
    sampling of the tonal variations of the result.
    So I make them 1" wide for the width of the sheet.
    This makes them long enough to be held down by the easel.
    As needed I'll use two to get the needed information.
    What they don't do for me is take the place of *all* exposure
    variations. They let me get really close very quicly.
    Then I'll do two or three full-size to get what I really want. Because
    there comes apoint where strips are useless and
    to continue using them is also a waste.
    My net benefit here is that I can compose on the easel and leave it
    stationary during and after the test strip process.
    So from a box of 50 I'll usually only need to cut up one or two sheets.
    dplotusnotes, Jan 11, 2005
  19. John Bartley

    stewy Guest

    I'd suggest getting some really thick card (2 or 3mm) or thin plywood. Chop
    out a frame slightly smaller than 10x8 or 7x5. Then cut out rectangles for
    card about 22-25mm wide, giving you 5 strips on the 7x5 or 8 on 10x8. Cover
    all but one strip & expose. Remove another strip and expose etc.
    stewy, Jan 31, 2005
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