[LargeFormat] re: Printing the Giant Pinhole Negative: A Question from June 4

[Guy Glorieux]

Thanks for the thoughts, Stephen .
We eventually successfully did get 3 contact prints from the giant paper
negative (as a reminder for those who missed the thread last summer:
this 150"x96" negative was made of 3 adjoining bands -each 50"x96" -
made from a hotel room transformed into a giant pinhole camera).
I will not go into a detailed account, but it was quite an adventure...
Each of the 3 contact prints has their own characteristics and by normal
standards for assessing print quality would be considered as a failure.
But given the nature of the imaging process (giant pinholin'), they are
really successful!
I hope to be able to put them on the web at some time.  But it requires
time, knowledge and ressources, all of which I currently seemto be
lacking.  In fact, I have not even been able to arrange a gallery show
here in Montreal...
Best,
Guy

----- Original Message -----
From: "SGHammond" <sghammond101@juno.com>
To: <largeformat@f32.net>
Sent: Sunday, January 12, 2003 3:24 PM
Subject: [LargeFormat] re: Printing the Giant Pinhole Negative: A
Question from June 4


Hello Guy,

I was reading your question posted on June 4, but I am not a subscriber
to this Large Format list and wasn't sure how to respond to the thread.
I very much like what you are doing and wanted to let you know my
thoughts...Maybe something from them will be helpful.

I would preface my ideas by saying that this approach I had thought of
sometime back may be too much of a hassle and may not work, as I have
not attempted it, but for the past few months I have been working
through solutions in my mind and on paper to produce large format
pictures.

So here we go:

A few years back I worked for a sign maker.  My job included operating a
CNC (Computer Numerical Control) router.  If unfamiliar with this
machine check out this link for a simple description.
http://www.thermwood.com/CNC_Routers_Explained.htm
Basically, it is a machine that can be programmed to automate cutting
tasks on either two or three axes.  The machine I used to operate had a
9' x 16' table...large enough for your needs.

My thoughts on a solution for processing a print from a large negative
utilize this machine.  One problem though is finding one and an owner
open to assisting in the developing process.  If this is accomplished,
here is how I would proceed.

The machine has a router head that could be removed and in its place a
small fixed light source added.  It is important to have the light
source project its light with a fixed spread and a consistent intensity
across this spread.  The width of spread and value of intensity will
need to be known when in the next step you program the software to do
the exposing of the negative. Also, as part of this light source you
should create a bracket for your filters if you need to manipulate
contrast on different areas of your negative.  With the light source
being so close to the negative and print you eliminate the need for a
16' ladder.

Using a CAD software program you would map out your negative into a
grid.  The grid would follow the width of the spread from your light
source.  Imagine mowing a lawn.  That "mowing" is what I am essentially
talking about.  The machine would move back and forth directly over the
negative and print exposing one section at a time.  This would allow you
to set up each area with great precision with its own exposure time
attributes by how fast it passes over a specific area. Here you are
letting the machine do the burning and dodging while exposing the
positive print.  If you do a test strip that covers a problem area of
the negative, you could adjust the times in the programming rather
easily without wasting the valuable large paper you acquired.

To eliminate wetting the negative and positive paper, I was thinking
that if you are exposing, let's say, a 6" spread of print at a time, you
could use a good old piece of glass that is 8' x4' that you would
manually slide along the negative as the light source passes overhead,
creating the necessary pressure for true contact.  You would only need
to move it every 6 passes or so, and it wouldn't be so large that it
would be too encompassing.
Also, to hold the two pieces together and down to the table,
strategically place lightweight two-sided taped would work I assume.

That is my simple explanation of what I had come up with.  As a
foundation of thought you could use this method to do a lot of effects
and tricks by programming the CAD software to control the machine in
almost any way you want...i.e.. purposely leaving out strips of
developing or making designs of exposed paper.  This, I guess, would be
the artistic license side of developing.

Anyway, that's the basics.  I hope that you get this and something
within is useful.

Take care,
Stephen Hammond