As some of you may know, I spent Pinhole day creating a giant 12 feet by 9 feet pinhole image of the Montreal landscape from one of the rooms of the Wyndham Montreal hotel.
The print was a real success - as far as we can tell from the paper negative. We are now working on how to create the paper positive. One of the central element in this project has been the decisions to make on (1) focal length and (2) pinhole diameter and thus (3) actual F/stop. The decison on pinhole diameter was hard to make because the weather forecast was calling for heavy snow on the 28th. But at the time we had to make the decison on the size of the pinhole, so that we could start exposure at 00:00hr local time on April 28, the weather looked much better than the forecaster's report. I ended up rushing back home on the computer and doing all sorts of simulations with Larry Fratkin's Pinhole calculator http://www.mrp at ???????/calcpinh.html and exposure calculator http://www.mrp at ???????/Exposure.html to see what would work best under alternative weather scenarios. Exposure scenarios were then adjusted using Guillermo's information on "reciprocity failure" compensation factors for paper - as mentionned in various emails on this list and also on his web site at http://members.rogers.com/penate/pinsize.htm I dare say that without Larry and Guillermo, we'd still probably be in the soup... My sincere thanks to them and that of my group for having made that information available on the web for everyone to use freely. Cheers, Guy
