I thought this would have been already asked, but there's only 3 pages in the paper neg forum and I can't see the answer (although I'm sure I'll see it as soon as I've asked such a simple question and feel like an ass about it). Anyway, seeing as I've just been gifted a jobo and enlargers, I'm getting ready for paper developing. One thing I've wanted to try for ages is a suitcase-based pinhole camera using paper negs. I've done it in high school many many years ago, and from what I remember it was along the lines of 'poke a pinhole in a shoebox, take a photo, develop, adjust your exposure time if too dark or light'. But this time I want to use real calibrated-sized pinhole (i've got a lot from Skink to use), I've got a real lightmeter (digisix), I can calculate focal length and f/aperture, all I need to know is what to rate the paper in EI terms to calculate exposure times. For the record I'm using Ilford Multigrade iv paper, in Multigrade liquid dev for now (maybe when that's out I'll try bromophen too).