Flashing Paper

[Les McLean]

Alex,

A couple of weeks ago I received an email from a fellow apugger asking for advice on paper flashing and I promised to send him a draft of an article I wrote some time ago for a UK based photo mag. I have at last found the time to do this so I will be happy to do the same for you if you would send me your private email address. My email is les.mclean1@btopenworld.com

[yeahyeah]

I have used the flashing method on MG quite a bit recently. Here is my method....

I raise the enlarger head as high as it will go, set the lens at the smallest aperture then make a test strip to find out the flash time. I used an otherwise unexposed piece of MG paper and used 1 second increments. After developing the paper in the usual way, I use the time where I first see non white. I have flashed both before and after exposing for the main print. I find it a particularly useful tool in printing.

[Alex Hawley]

Thanks to everyone for all the good tips. This isn't as hard as I was trying to make it. Somewhere down the road, I'll post some results in the Technical Gallery.

[Aggie]

Hmmm a forum full of male flashers!

[Alex Hawley]

Now Aggie, there you go opening up a realm of possibilities.

[Seele]

I always have more than one enlarger in the darkroom; when required I set up another for "flashing" which I prefer to call "pre-exposure", which is a way of hyper-sensitising the paper.

What I do is to have the other enlarger set up in a repeatable way, for instance, racked to maximum column height, lens standard racked to top position, minimum aperture set on lens, etc etc. Then I do a test strip with a Durst test strip gadget and process it normally. Once the test strip is ready I examine the steps to identify the greatest exposure the paper can take before registering a density on the paper, and that's my pre-exposure for this batch of paper, which I write on the box.

In that case, any additional image exposure will start registering on the paper so as to increase highlight details. As this is forcing a linear exposure into the log image exposure, it has practically no effect on the midtones and shadows.

[Ka]

Les McLean's article on Flashing is Excellent!!!!

Anyone who is still curious about flashing should do to read it.

I have saved it and printed it out to share with my flash-needy colleagues.

ka

[glbeas]

Les and Don, I have a question about flashing VC paper.
What are the qualitative difference between flashing with the 3 filter or no filter, just the 5 filter or just the 0 filter? I've seen little mention of any testing on this aspect and was curious of any results gotten so far before I start experimenting myself. I seem to have so little time in the darkroom lately it's going to be a while before I have a complete set of results on the paper I want to use.

[Donald Miller]

Gary,
You raise an interesting question. I haven't done any experimentation along the lines that you suggest. My initial thoughts are that there may be a different result between the hard and soft filtration. The hard filtration would seem to be counter the result that one wants to obtain.

What we are doing in preflashing the paper is bringing the exposure threshold of the paper into play sooner then it would if a normal exposure were done. This emulsion that is most involved here is the low contrast (yellow or green light) emulsion rather then the higher contrast (magenta or blue light) emulsion. Since the preflash exposure affects primarily the highlight regions of the print, the filtration that would seem to be effective would be soft or no filtration. As we move toward 3 or 5 the emulsion that we wish to addresss is being increasingly removed from the process.

Those are my thoughts based, as I said, on no testing. Good luck.

[glbeas]

I can see the reasoning behind the low contrast flash. What I was thinking concerning the high contrast flash was to bring highlight local contrast up. I suspect the threshold exposure for each emulsion layer is going to be different and differing contrast filters will give a different tonal separation in the highlights. This is all just theory right now and the reality may be miles away but I think it's worth looking into.