Pre-exposure Flashing

Silver Gelatin Pre-exposure Flashing (a PDF version of this is also available)
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Silver Gelatin Print Processing Steps
setup, basic steps video
making a contact print
making an enlargement print
cleaning up vimeo.com/506852727

Printing: Pre-exposure Flashing

This technique is best used with silver-gelatin enlargement printing.

Sometimes, a negative’s densities (highlights when rendered in the print) are such that they cannot be exposed without either severely blocking up (over-exposing) the shadow and mid-tone values or, if burned in, leaving unpleasant visual edge marks beyond the highlight areas. 

The paper may be given an overall threshold exposure to white light before the main exposure to the negative. This can bring the extreme tonalities closer to each other and render a more harmonious and luminous print. We refer to the method as “flashing,” “pre-exposure flashing,” or “preflashing.”

To flash a print, you will follow this general pattern:

  1. Set your enlarger up as you normally do for enlarging a negative, including arranging the enlargement height, the negative, filter, and easel.
  2. Flash the paper.
  3. Expose the flashed paper to the negative.
  4. Process.

Some of these steps are detailed below:

  1. Setup for enlarging the negative by setting the enlarger height, filter, and easel blades. This is a normal part of your workflow.
  2.       A. Establish the flash exposure
    1. Remove the negative from the enlarger. You may take out the negative carrier too, but it is better to leave this in to minimize light spillage.
    2. Reduce to lens aperture to its minimum (f16 or f22).
    3. Set the timer to 1-second intervals.
    4. Replace the filter (in Step 1) with a #0 
    5. Cut a strip of unexposed paper to about 4 x 10 inches in size. Make a set of marks (Sharpie or similar indelible ink)along its length, about 1 inch apart, and number each of these from 0 to 8. Place this in the easel so that about 2 inches of the width of the paper is under the easel blade while the remaining portion, along with the numbered marks, is visible within the easel window.
    6. With a piece of opaque cardboard covering up all of the paper up to mark 8, tap the exposing timer. Move the cardboard to mark 7, and expose it for another second, and so on, until you get to mark 0.
    7. Process this test strip.
    8. After fixing, towel dry the test strip and examine it in white light. Locate the exposure that has the lightest discernible grey tone. The flash exposure is one step less (lighter) than this.
      At least the “0” step should be clear white. If there is no clear white step, then set the timer to 0.5 seconds and repeat this section. If there is no discernible grey by the “7” step, then open the aperture by 1 stop and repeat.

      B. Flash the paper

    9. Leave the enlarger set up as in the first section (A) of this step.
    10. Cut a strip of unexposed paper to about 4 x 10 inches in size. 
    11. Reduce the curl as much as possible, and place the sheet within the easel frame. It may be necessary to tuck corners or the slightest edge of the sheet under the blades to help keep it flat. 
    12. Flash the sheet with the exposure time established in step 2.B.8
    13. Remove the flashed sheet of paper and store it in a light-proof box or drawer. You should lightly pencil a note on the back to remind you of the pre-exposure flash time. Also, make a note of the enlarger height, aperture, and filter #.

      C. Return negative to enlarger

    14. Go to step 1:Reset the enlarger so that you are ready to enlarge and expose your negative, checking the height, filter#, focus, and aperture.
  3. Return the flashed paper to the easel, this time placing it under the blades and at a location that allows you to make a step test across as full a range of tones, and especially the highlights, as possible. Do a step test of at least four exposure times.
  4. Process the exposed paper. Towel dry and examine the test print in white light. Find the most suitable exposure and repeat the cycle with a full sheet of paper* from steps 1 to 4. *Note: Always mark the back of the sheet so that you know how to return it to the easel with the same orientation.

Make Notes

Either in pencil on the back of the print or, more preferably, detailed notes in a notebook with a corresponding number penciled on the back of the print: any negative information/numbers, time and date of processing, solution temperatures, enlarger height, lens aperture, contrast filter, development time, developer type and concentration, and any other process notes such as dodging and burning.