Thankyou Ralph. Why 3.2? because that's as low as my Gossen Digipro metre will go , and I think thats the ISO for paper? Ilford Multigrade. Exposure factors??? well Im floundering here. I measured the pins /pinholes and the focal lengths, fed them into the pinhole calculator and it came out with these exposure factors. I have it in my tiny mind that I have to do some sums........??!! then I will have the exposure times Im Looking for.