----- Original Message -----
From: "Christopher C. Pearson" <[email protected]>
> Hello. I apologize for such an amateur question.
Don't worry, we all are pinhole AMATEURs here.
I am not a professional, I am an amateur...
Amateur is the French word for LOVER.
my paraphrasing of Imogen Cunningham's words.
> I've attempted to make my first pinhole camera with a Quaker Oaks box. I
> poked my pinhole through a piece of tin (the kind made for cooking pans)
and
> taped it to the Quaker cylinder. I'm using Ilford 5X7 Multigrade 4 paper.
> Indoors, I'm getting a proper exposure when exposed for about a half an
> hour.
>
> When I bring the camera outside, and expose for less than a second, my
> picture is totally black with no detail.
You most likely have light leaks. Make sure your box walls and lids are
completely opaque to light and that there are no light leaks when closed,
the only light leak should be the pinhole!
As for the exposure:
I wish I could give you a number of seconds or range of time (10 - 40
seconds, for instance) you can use, but they are as useless as if I tell you
to use 1/8 second or any other time or range of time for when you use your
glass lens camera. Time alone is nothing.
Exposure is not just time, it is a combination of time and aperture. You
can practice and practice pinhole imaging with your camera set up until you
get a good idea of how fast it is under different light conditions (perfect
technique for many). But if you are like me, with not a lot of time to
practice and/or not a lot of money to expend on film/paper and rather want
to have a more precise point of departure (exposure time wise), then, you
have to know the f/stop of your set up. Unfortunately, to know the f/stop
of your pinhole camera, the pinhole has to be measured. Not all of us have
a device to directly do that measurement. Luckily, there are ways to
estimate and also ways to directly measure the pinhole diameter. Some of
then include actually measuring its diameter with a ruler in graduated in
millimeters and a magnifier (works well when the pinhole is really big).
You could also do measurements by projecting the pinhole with either an
enlarger or a slide projector or you could even use a cheap flat bed
scanner. I wrote a humble article on how to do this, if interested you can
find it in my pinhole page at:
http://members.home.com/penate/pinhole.html
While there, check also the article on Pinhole exposure, which has a
reciprocity correction table for the paper you are using.
Guillermo
