preflashing Direct Positive paper without an enlarger?

[Eric Woodbury]

Jim, I pick the one that is just before a change in paper white.

[younghoon Kil]

In the field, I set the ISO to 3, put a diffuser filter in front of the spotmeter, measured towards the dark part of the scene I was going to shoot, and then set this exposure to Zone II.
After pre-flashing, the actual exposure was taken with the dark part set to Zone III.
In this way, my first and second Harman Direct Positive Papers was developed very successfully.
But ever since then, all Harman Direct Positive Papers has been developed white.

When measuring exposure with a diffuser filter in front of the spotmeter, I wonder if it is correct to measure the dark part of the scene.
And after pre-flashing, do I have to shoot within 1 to 2 hours?

I was wondering if you could give me some advice.

Thanks,

[Pere Casals]

I don't have an enlarger.

Id like to try out some DP paper.

I do have flashed, and strobes... Anyone prefacing with a strobe/speedlight set to 1/32 or 1/64? or any other solutions without an enlarger?

Thanks...

You can preflash the paper in camera just before shooting, just point the camera to sky and defocus a lot, meter and apply the bellows factor (from the defocus bellows extension), in that way you may expose the preflash amount that the particular scene requires. Of course you may also preflash all paper in the holders at home, also with the camera pointing to a wall that's illuminated uniformly, for that I had been using a TV displaying a white screen.

If you do in camera preflashing it's important to use a lens with little fall-off, so a long lens with a large circle is suitable, also stopping a bit is good, and finally as you defocus the circle grows so you take the center of it, also mitigating fall-off.

Finally, if any preflashing method, you can make a "test strip". This is preflashing the paper several times and each time you insert the dark slide of the holder (say) half an inch, so in a silgle paper sheet you have several bands with different amounts of preflashing.

You may develop that "test paper" to see at what exposure level you start noticing fog density, and of course you may shot an scene with that "test paper" to see the practical effect.