ok all you pinhole enthusiasts

[mysteryscribe]

ya gonna have to explain that to me.

 

[JamesD]

There's a certain low level of light which will not expose paper. I've read it described as "chemical inertia," meaning that the photons hitting the silver just aren't enough to start the reaction. The analogy given was pushing a car: it's hard to get the car rolling when it's stopped, but once it's rolling, it doesn't take as much of a push to keep it rolling. Similarly, the few photons striking the emulsion in very low light just aren't enough to get the silver changing to begin with.

So, flashing is a technique used under an enlarger (or in a pinhole camera, I would assume) which gets the chemical reaction going, so that the light hitting the emulsion won't have to "push" as hard, allowing very faint light to keep changing the silver in the emulsion.

Basically, what you do is expose the paper to light (enlarger light, room light, lamp light, whatever) either just bright and long enough to barely fog it, or just less than enough to barely fog it. You'll have to develop it, of course, to figure out whether you're giving it enough light (or make sure you're not giving it too much). Once you've figured out the right intensity and/or duration of the flash, you flash another piece of paper and load it into the pinhole camera.

Which brings us to the reason why I asked in the first place: if you try flashing the paper, it might give the emulsion enough of a kick in the seat to record your low-light scene.

Beware, however: I've also read that flashing is temporary. If you flash a piece of paper, then put it away, the effect will disappear, and you'll have to flash it again. I think this applies to flashes which are just barely too little to fog the emulsion; once you have fogged it ever-so-slightly, I think it keeps the fog--but I'm basically guessing on this. I have no idea how long it takes the emulsion to forget that it's been flashed.

 

[JamesD]

Do you suppose we should start a new thread, since we're not really talking about Pinhole Day anymore?

 

[mysteryscribe]

We used to do that with slide film to kill some of the contrast. I never heard of it for this purpose. i would think you would need a stronger light that the low light of the studio. Maybe aim it out the widow a the sky for a second or two then try it. Im not sure.

Start the thread, call it what ever you like and ill join in. This paper negative thing is going to need a lot more understanding than i thought. It might well be like the original film emulsions. Each situation called for a little differnt thinking. It's really fun but not as realiable for me as film.

 

[JamesD]

All Righty, I'll start a new thread, and link it to this one. Then, I think it's off to bed for me. Gotta get up early, unless the lightning keeps up.

 

[mysteryscribe]

I have several pin hole cameras now and I have decided to::::: If i can find the shells for my shotgun (haven't fired it in 20+ years) to throw them into the air and put me out of my misery....

After I do that, I am going to cut a roll of film into sheets, load them into my film holders, and then develop them without any exposure.... Since I will miss wasting my time with pin hole cameras and need my daily anger managerment practice.

After that I am going to patch the holes in my studio walls. I'm a retro photographer Pray for me...