> - Is my brass shimstock thinner than your silver
> sheet? I can't remember the thickness of the brass
> stuff, but it is foil-like, from the auto parts store.
Maybe, maybe not. Can't know without measuring. Probably doesn't matter
much because since you are removing metal, the foil will be thinner at
the edge of the hole anyway. I use .003 because it is easier to work.
No point in having it so thin it crunches up on you.
> Also, I know that aluminum makes for bad holes because
> of the tendancy for the foil to tear and burr and crumb
Right. Aluminum is brittle and work hardens so badly that it is pretty
useless for pinholes. However, the first camera I made had aluminum
holes, and it worked surprisingly well. Don't try to go beyond the
initial poking however. The metal won't tolerate any working.
> up. Is silver superior to brass? I would think it
> behaves similarly to aluminum...
Not at all. Working with brass is horrible compared to silver. Silver
is malleable, ductile, a dream to work with. That's why it has been used
for jewelry for so many centuries. (I did my MA work across
Photography/Jewelry. I learned to absolutely love silver. The fact that
silver is so important in photography is a coincidence that has intense
meaning for me.) You can work silver a lot longer before it gets nasty.
Maybe gold would be better, but hey, silver's cheap, too. For about $35,
you can make a pinhole a day for the rest of your life. Maybe. Anyway,
an ounce of silver rolled out to .003 in a 1/2" roll is one heck of a
long strip. Have the dealer supply it annealed (heat treated). This
softens it, makes it even easier to work with. Remember, as you work it,
the metal becomes harder. Work it long enough, and you can either
re-anneal it, or it will be so messed up you ought to be happy to throw
it away and start over.
> - Also my experience has shown that there is an optimal
> hole size, (no measurements; i don't have access to a
> microscope) and if I try to make a hole smaller, the image
> i get is suddenly fuzzy. Is this diffraction, or just
> imperfect hole results?
I would bet lunch that if you look at the hole with a microscope, you
won't believe the junk in it! Junk adds incredible horrible diffraction;
look, every edge makes diffraction. When you've got measurements, let's
talk about optimal hole size. Otherwise, we're just guessing, and I don't
like to comment when there are wildcard variables.
Your can cameras sound like a lot of fun. My first camera was a two
holed semi-quaker.
Glad to hear the enthusiastic comment on Eric's book; I think it's a
classic. I hope I'm not too blatently self-promotional if I mention that
the cover is one of my images.
Larry Bullis
Shoreline Community College