Pre Flashing Paper Negatives

[@wabashamj]

thanks Joe, your videos are always full of useful information. I have been given 100 sheets of Kodak polycontrast F from 1974 which I will have to learn to preflash. So far I've been cutting to fit the 4x5 but I'll eventually make an 8x10 pinhole. Great videos!

[@Joe_VanCleave]

@Gregg: The light stays stationary during the preflash, but I ensure that the paper remains near the center of the circle of illumination on the table. For 8x10 paper and smaller, the circle of illumination at a 30" distance is large enough that the lighting is pretty even from center to edge of the paper.

[@GreggObst]

Thanks for the clarification Joe.

[@Joe_VanCleave]

Urbanimage: My enlarger requires exposure times of less than 2 seconds, even with the lens set to F/32. Given the inaccuracy of my enlarger timer at these short durations, especially in the colder months when the timer may be running even slower, it helps with exposure accuracy to have a dimmer light source and use a longer exposure time.

[@Paul1287]

Having trouble finding a similar bulb in cool white. Is soft white OK to use?

[@Joe_VanCleave]

Yes.

[@bnybnybny]

Thank you so much for all the Information! Why dont you use your enlarger as a lightsource for pre flashing? Is there a particular reason? I want to try do a Papier neg large format with a homemade pinhole tomorrow.. thanks for all the Good inspiring Input

[@Joe_VanCleave]

When I did preflash tests the exposure times, even with the lens at f/16, were only a second or two, not long enough for accurate exposures, given the inaccuracies in my mechanical enlarger timer, especially in the cold of winter where motorized clockworks are problematic. So I needed a light source dimmer, permitting exposure times closer to 10 seconds.

[@Joe_VanCleave]

Glossy paper will show the most detail, either when scanning or contact printing.

[@Joe_VanCleave]

I am using Freestyle Photo's Arista brand resin coated grade 2 paper.

[@TheCampbellseth]

Joe Van Cleave What iso do you rate this paper at? Thank you for sharing your knowledge and discoveries on this channel

[@Buildasteamengine]

Great info - I my have missed this but did you mention the weight of the paper you are using for your negatives.

[@floydburkett630]

I know this is an old video however may I assume that you develop your test strip after the pre-flashing. I'm new to this.

[@Joe_VanCleave]

Yes!

[@RogerHyam]

Hi Joe, Do you have thoughts on in-camera pre-flashing? I only have access to a community darkroom so it isn't convenient to pre-flash before going out on a shoot. I was considering metering a scene then making an exposure of, say, -4 stops through a piece of opal perspex before the main exposure. What do you reckon? If it isn't raining at the weekend I'll maybe give it a go. Roger

[@Joe_VanCleave]

I tried this some years ago when I was doing a version of an Afghan box camera, but using an old Polaroid Model 800 camera. I used a thin piece of white translucent plastic over the lens, it did seem to work, though I can't recall there was still a hot spot caused by the sun. IIR, I was also using the Polaroid camera to contact print paper negatives. I had a two-sleeve portable darkroom box. I'd develop the paper negative inside the box, then quickly dry it, then load it into the Polaroid camera sandwiched to another piece of paper, along with a thin sheet of clear glass. Then the Polaroid was closed up and removed from the dark box. Then the exposure with the white plastic piece over the lens, with the camera pointed at the sun. Then the Polaroid was loaded back into the dark box and the print developed. If I was doing this again, I have a piece of white foamcore board and point the lens at the board, for a more even illumination.

[@Joe_VanCleave]

Those are good results! I was thinking that your 7s preflash that seems a bit more concentrated in the center might work well for some types of images, where you want a bit of a vignetting around the edges; the center would have lighter shadows, the edges darker. Well done.

[@lumn8tion]

@@RogerHyam well done!

[@chuck4x5]

Nice, I'm proponent of pre flashing in the darkroom. I live where there is a lot of atmospheric perspective in my landscapes.

[@jamesdunlop8704]

If you use manufacrured photographic paper as a negative ,when you put it in the enlarger and print through it dosent the manufactures name on the back of the paper come out on the print?

[@Joe_VanCleave]

Yes, if the paper does have a watermark. Most of the B&W papers I use don’t, such as from Ilford or the Arista brand sold by Freestyle Photo.

[@DavidHancock]

Does flashing alter the exposure ISO?

[@Joe_VanCleave]

It increases the shadow detail without affecting much the highlights. So no, not a real ISO change, more like reduced contrast.

[@TheCampbellseth]

Joe Van Cleave What iso are you rating the Arista paper at? Once again thank you for sharing all your hard earned work and discovery on this channel

[@thedrill6705]

for some odd reason, he is very similar to Walter White from BB.. and he also probably knows some basics about chemistry because of his interest in photography... Im concerned ;-;

[@pepeg.luthier566]

great!