I’ve yet to try this maneuver.
A big part photography’s appeal to me are the hundreds of forums, blogs, and videos with information on how to use a particular camera or process a certain film. The best part: everyone who contributes is an expert, just ask ’em.
I got my hands on a pinhole camera this weekend, Ilford’s 4×5 Obscura. Having never used a pinhole camera, or shot 4×5, I figured I’d triple down and shoot some direct positive paper.
Long story short: I consulted the world wide web, took bits from here and pieces from there, made a few judgement calls, and it worked out well.
Below is my first image and I’m quite pleased.
Should one want to replicate these results, here’s all the nitty gritty:
There was no pre-flashing funny business, the paper was just loaded into the camera under a safelight.
I metered off the building with the “myLightMeter” app (how did people shoot film before smartphones?). After obtaining a reading for f8, ISO 100, I plugged the shutter speed into a homemade google sheet with exposure calculations/conversions.*
Taking the picture was the easy part, in this case it was a 3 minute 43 second exposure.
I developed the paper in fresh** Ilford Multigrade Developer, 1:9 dilution, for 2 minutes (ymmv, I was just eyeballing it), used a stop bath for 1 minute, and fixed the image in TF-5 for 3 minutes.
Let ‘er dry and I was good to go. The paper curled quite a bit, but that may have been because I used a heated drying rack.
Ilford Obscura Pinhole
Harman Direct Positive FB
Ilford Multigrade 9:1, TF-5 Archival Fix
* You’re welcome to use this sheet to calculate your own exposures. The sheet is locked down so all you can/need to change is the shaded cell corresponding to the shutter speed at f8 ISO 100. Good practice is to make a copy to use/edit yourself. Keep in mind that this sheet was developed only for the Obscura camera and Harmon Direct Positive FB paper.
If you’re keen you’ll notice that the calculations use an ISO of 1.5625 for the paper and an aperture of f256 for the camera, while Ilford reports values of 1-3 and f248, respectively. You’d be right, but this just worked.
**Most internet experts agree, fresh developer is necessary for this paper. I don’t have an opinion, I’ve only ever used fresh developer, but, again, it just worked.