I finaly did some more "try it and see" tests and found out a couple of things.

The pinhoe used in conjunction with the camera lens is best.

The smaller the pinhole the less sharp the image becomes.

My thaught was that a smaller pinhole gives a sharper image but not so. The camera being used is a 4x5 and the pinhole is .018 or .020 aprox, brass shim stock blackened with a solution stained glass workers use to patina the leadding.

The film being used is Kodak T max 400, exposures are quite fast, 1/2 -1 sec in sun, 10 sec in shade. when I get someone to post the pictures you can see some examples. (I am computer illitteriate...)

Kevin, the pin hole size and sharpness is also related to focal length. There are optimal pin sizes for a particular focal length.

I remember someone posting a link to this, so I Googled it again..

http://www.pinhole.cz/en/pinholedesigner/

I remember someone posting a link to this, so I Googled it again..

http://www.pinhole.cz/en/pinholedesigner/

And, in general, the smaller the pinhole, the greater the diffraction effect.

Pinhole design involves several trade-offs. Focal Length; pinhole size; light frequency; diffraction; size of the minimum acceptable size circle of confusion; are the ones I can remember off the top of my head.