Hi Patrick So sorry to hear that your pinhole did not work; it does happen.
For what it is worth I think that the problem was the calculation. >From experience I would say that your exposure should have been around the 3 minute mark. Particularly for light toned subjects. The way I come to this is as follows: I have a camera with a focal length of about 7 inches. On a normally overcast day my meter reading is around the 16 EV mark. This using resin coated paper gives me a normal exposure of 6 minutes. The pinhole I use is 0.024" Pinhole is an imprecise art and the way I would make the translation in my head is; 7" is nearly twice as long as 4" so I would require a quarter of time exposure all else being equal = 1.5 mins. The pinhole is nearly twice the diameter so lets say three times this exposure = 4.5 mins If you include alot of sky and light toned buildings then the time is drastically reduced Finally from what you have said about the total blackout I would reassess this calculation and try at 3 maybe 2 minutes. If you passed the needle right through when making the pinhole the likelyhood is that the hole is larger than 0.148. Therefore the exposure would be shorter. If you can see a trace of detail amongst the black then you are not that far off. What the heck try 1.5 or 2 mins Now if you understood this you deserve a degree in foreign languages. I do most of it in my head and then err on the side of ignorance. If anyone wishes to take issue with what I have just said, please do! Alexis > Friends, > I have taken a look at the current offering of this year's pinhole day > images. All are terrific! What a wonderful project! > > I had a somewhat disappointing pinhole day, I am sad to say. I ran a very > small pinhole "workshop". (I use quotes, because it was really just a few of > my friends and I was only qualified to run this "workshop" because I had > made and used a pinhole camera and they had not, more or less.) > > On Saturday we built our cameras. On Sunday we went out to shoot. As many > already know, it was VERY rainy in New York, but we were lucky enough to > step between the raindrops. We took pictures with oatmeal box cameras. Focal > length approx. 4"; pinhole approx. .0148" (#12 needle); therefore approx. > f/256 (rounded). We shot on Ilford Multigrade; approx. ISO 6?? An example > exposure was approx. 10 min under heavily overcast skies. > > Here is the root of the question: All the negatives were black! I assume > that we drastically over-exposed the paper. I do not think that it was > fogged, but I suppose it is possible. The cameras were not light-leaky. > > Does anyone have any clues? Luckily, we all took a turn with my pinhole > camera with Polaroid 669 film. Those were fine. But even so, I have a group > of disappointed Pinholers on my hands. > > We will try again soon (obviously too late for this year's pinhole day and > too early for next year's) so any help is appreciated. > > We did all have a great deal of fun, but it would have been nice to send > everyone home with their own photo, taken with their own camera. > > --Patrick
