Pre – Flashed Paper Negatives for Pinhole Photography

To achieve a paper negative with a wide contrast range it is helpful to pre-flash or expose the paper very briefly to white light in the darkroom before exposing in your pinhole camera. This pre-flash will reduce the contrast of your negative and also decrease the exposure time. Pre-flashing slightly increases the exposure in the shadow detail areas without affecting the highlight detail.

Each brand of paper will require its own pre-flash exposure. Use the following steps to determine the correct exposure for your brand of paper.

1. Set enlarger to F16 and insert a # 3 filter. Set the head to the highest position at the top of the column.  Alternatively you can use a dim light bulb suspended 3 feet or more above your paper. Try a 7-watt bulb for this.
2. Make a test strip with 5 sets of 1-second exposures.
3. The correct pre-flash is the exposure for the first strip that is barely visible. If your test sheet is all white increase the exposure per strip, if it is too dark, decrease the exposure for each strip.
4. Write down the enlarger station, head height, f-stop and exposure used in your notes for further reference.
5. Expose all the sheets you will be using and keep them separated from your un-flashed paper. I put mine in the bottom of the black bag under a piece of matte board.

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