Single filtration times

Discussion in 'Enlarging' started by PVia, Nov 29, 2007.

  1. PVia

    PVia Member

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    Hi all...

    Is there a ballpark figure for the change in exposure time when using single filtration for contrast changes?

    I know that grades 4 and 5 are generally double the time, but how about going from grade 2 to grade 3, etc...?

    Thanks!
     
  2. Stan160

    Stan160 Member

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    It depends on the paper, you need to read the data sheet. Most papers are rated at one speed for grades 0-3, and as you say, half that speed for grades 4-5. The Ilford papers I use certainly behave this way.

    The Fomatone MG Classic I tried for the first time recently has a different speed rating for each contrast grade according to the data sheet. I was split-grade printing so didn't have to make allowances (well, I did of course, but it was built into the process rather than having to calculate the different when switching grades).
     
  3. Dan Henderson

    Dan Henderson Member

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    That very question is what drove me to split grade printing. Despite the instructions saying that there is no change in times between grades 0 and 3, and 1 stop when going to 4 or 5, my experience was that the time wandered all over the place when I changed filters. I would do a test strip with one grade, determine the highlight time, then change filters to get the shadows right....which typically affected the highlight time. Changing that time again might affect the shadows...and round and round. It seemed like I spent half of my time in the darkroom trying to pin down time and grade to get the shadows and highlights that I wanted. Now, 2 tests and I've got my base exposure nailed.
     
  4. Ole

    Ole Moderator Staff Member Moderator

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    All I'm certain of is that the EM-10 gives consistent exposure times across all grades, by adjusting the aperture to give the same reading in the highlights.

    It doesn't take many test prints to save the cost of a meter...
     
  5. Lee Shively

    Lee Shively Member

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    My starting point is to consider the speed of the paper, what exposure is required without a filter and then I figure using any filter from 00-3.5 will cost me one stop. Then from 4-5 it will cost me one more stop.
     
  6. Shawn Dougherty

    Shawn Dougherty Member

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    Indeed. If you haven't tried split grade I highly recommend it. There is so much control built right into the process I don't use MG paper any other way.