I would really be interested in hearing some ideas about the right way to flash prints during enlarging. What exactly is flashing? When is the technique appropriate and what is the best way to do it. A friend told me he has a seperate enlarger in his darkroom just for flashing then he switches the easal to his main enlarger for printing. If this is a good idea, does the secondary enlarger need to be the same negative format as the main enlarger? Also, I have heard that printers use a grey card exposed negative for flashing purposes. I really want to learn to use this technique and would appreciate the experiences of people in this community. Thanks-so-much, Paul

-- Paul MInkus (dkurtz@mc.net), December 08, 1999

Answers

Print flashing is one technique for handling negatives with a very long tonal scale, when normal printing would give no detail in either the highlights or shadows. It works by giving a very small even exposure to the while paper, thus raising it slightly above the threshold. It gives you some detail in the highlights that you wouldn't otherwise get. It can be useful for negatives that have normal density and some very dense portions.

Flashing can also be used to give black borders.

The secondary enlarger can be any format.

-- Alan Gibson (Alan.Gibson@technologist.com), December 09, 1999.

I think Alan's post is a bit brief in some details.

Flashing is used to give highlight detail in prints where burning is difficult or impossible (for example because of the shape of the borderline between light and dark areas). The flashing itself is a *sub*-threshold exposure (just like pre-exposing film), but the little extra light given to the flashed paper in the highlight areas is then sufficient to get over the threshold, thus giving some detail. To find out the flashing exposure, make a test strip: Carefully note the height of your enlarger head and the aperture of the lens. Cover half of the test strip (along its length) with an opaque ruler or a similar object. On the other half, expose a series of test areas in sufficiently fine steps. Develop, fix, wash as usual. The flashing time is the time for which you exposed the last test area still purely white.

Now when you have a difficult negative, prepare a sheet of paper by flashing it with the time and settings you noted. Then enlarge the negative on the pre-exposed sheet.

I would not recommend using a negative to flash unless your enlarger gives too much light (thus requiring inconveniently short flashing exposures) when used empty.

A second enlarger for flashing is no must, but it can be quite convenient when your first attempt failed. Its format does not matter at all. (In fact, you might even be able to flash with a naked bulb not too close to the sheet of paper to ensure even illumination.) With an additional enlarger, all you have to do is walk over and flash another sheet. If you have only one enlarger, you have to remove the negative, set it to the right height and aperture, flash, then re-adjust to the right height for the negative ...

If you flash too much, your highlights will be fogged, i.e. grey rather than white. Then try again, flashing a little less. You may also combine flashing and burning, or flash only parts of the sheet.

-- Thomas Wollstein (thomas_wollstein@web.de), December 09, 1999.

With one enlarger it is more convenient simply use some diffusing material as a filter under the lens while flashing. It is not necessary to take negative off or move the settings. Of course the proper flashing time is different with different negatives, but you have to do test strips anyway.

Simply put the diffusing filter under the lens, give the flashing exposure - say one second - take the diffuser off and give the exposure - ten seconds maybe. Fast and simple. The diffusing material can be a piece of tracing paper or cover of a video camera lens or anything which gives even illumination.

If you have to take the negative off and adjust the enlarger again for every test strip, you probably don't do enough test strips....

Sakari

-- Sakari Makela (sakari.makela@koulut.vantaa.fi), December 15, 1999.

Local flashing is useful for slightly darkening edges and corners of prints, and darkening distracting highlights in those areas. This tends to focus attention on a main subject nearer the center. It also helps when the top of a picture has a bright white sky. A small flashlight with the light lowered and diffused by several layers of masking tape works well. Smoothly sweep the light a few inches above the edge of the paper.

-- jim jones (jjones@greenhills.net), December 18, 1999.

If you have one enlarger, like the most of us, I suggest you to flash more than one sheet at the time. Than store those sheets in a separate, well marked box. When you need to flash, you pick a sheet from that box. Simple...

-- Mattia Vacca (mattiav@tiscalinet.it), January 17, 2000.