[LargeFormat] Re Worldwide Pinhole Photography

[Guy Glorieux]

----- Original Message -----
From: "Clive Warren" <
>
> Guy, talking of filters you have a lot of experience with pinhole
> photography. Do you use filters with your pinhole cameras?

Clive,
Sorry for the belated reply.  Things have been busy here because I'm
giving a pinhole workshop on Sunday and the following week, on April 28,
for the Pinhole Day, I'll be converting a room of the Wyndham Montreal
into a giant pinhole camera!

The image will be printed on Ilford RC VC paper, with a yellow filter on
the pinhole.  I'll be working with 3 strips of 50 in. x 9 feet from a
roll of 100 feet.  The pinhole should be about 0.1'' diameter with a
focal length of 10 feet.  This works out an f-stop of F-1200.  With a
yellow filter and paper at ISO 3, this should work out to an exposure
time of about 1.5 hrs on a sunny day.

There are no reciprocity failure charts for paper, but it is just as
real as for film.  So I'll have to make some tests before next week but
I expect to end up with an exposure time of maybe 8-12 hrs.  I just hope
that it'll be sunny weather outside.  If it's rainny, I can either move
the paper closer to the window and shorten the focal length to open up
the F-stop or work with a larger pinhole diameter and get a somewhat
more blurry image.

The plan is to calculate the focal length/F-stop based on the weather
outside so as to be able to open the shutter at 00:00hr on Sunday April
28 and to let the exposure run until 24:00hr.

That's quite a few pints of beer down the throat...!

> Have been thinking about use of paper rather than film - do you have
any
> recommendations for a low weight paper that may be suitable for
contact
> printing?

I'll be using RC paper and make 4' x 8' contact prints.  What you do is
you soak the paper negative and the unexposed paper positive, squeegee
them together and do you exposure.  I have not yet got around to making
tests but I do not see any major difficulties here if I managed to get
through the first stage of processing the paper negative.  I'll be using
wallpaper tanks to roll and unroll the paper in the chemistry.  Washing
and drying will be the tough parts.

I did make some paper negatives last week using fiber paper and there is
a wonderfull texture in the fiber that is worth trying to keep.  It may
be a good idea to try waxing the paper, although I've never done that
myself.  Obviously, you're going to have to make some test strips.  I'm
not quite sure what the B&F density would be for paper, but it's quite a
bit more than film...!  So, if you plan to expose the contact print
outside in the sun, remember that you'll need to use a yellow filter of
some sort to prevent your excessive contrast in your positive.


>
> Maybe a scan and invert is the easy route but it seems to go against
the
> grain for such a beautifully simple photographic process. The print
should
> really be silver rather than silicon.
>
I'll vote for that!

Cheers and happy pinholin'

Guy

P.S.  If you're interested, I have a web site (still in the making)
about my Hotel Room Pinhole Camera project at
http://www.zeroimage.com/Guy/PinholeHotel.html
You can access the Great Wall Pinhole Camera project from there at
http://www.zeroimage.com/WPPD2/The_Great_Wall_pinhole/introo.html