Re: Re: making a pinhole

----- Original Message -----
From: "ragowaring" <ragowaring@btinternet.com>

> Has anyone ever made a pinhole by photographing a circle?

I have, but have not use those pinholes to make images, though.

> I was thinking that if you can make a focal plate by photographing a
> printout of one, how about making a pinhole using film in the same way!
> It would be accurate, have negligable thickness, perfectly round and you
> could easily choose the diameter of the hole. Other shapes become instantly
> possible, stars, ellipses, squares, the sky is the limit.

I made those pinholes when doing tests for zoneplate making. The "accuracy" you
talk about is not that easy to achieve, though, in other words, unless you are
able to measure the first pinhole you make, you will not know if the distance
SLR to wall (where you place the "big paper pinhole") is giving you the
magnifications, reducctions rather, you aim for.

> Does any one have experience of this method or any ideas. It would
> certainly solve many problems and I cannot see any being created - all
> except one; is a dense negative sufficient to create a totally opaque
> surround for a hole?

I suggest you use lith film processed in lith A+B chems. The blacks, BTW, are
not absolutely opaque, but their density is so great compared to that of the
film's base+fog that is does not matter.

> And if this is a perfect solution, I know that pinhole is not always about
> perfection, but it would open up many possibilities. :-)

That of "non-round" pinholes, like those you mention above plus slits, are
definetely possibilities worth exploring.
Received on Fri Mar 15 18:36:17 2002