[LargeFormat] The Montreal Wyndham Hotel Giant Pinhole Camera Project (update)

[Guy Glorieux]

Hi friends,

I thought that some of you might be interested in an update on our
project to turn a romm of the Wyndham hotel in Montreal into a giant
pinhole camera and to do a wall size pinhole image of the Montreal
landscape.

Things are going on as well as could be at this stage and the only dark
spot I see  is that the weathermen are calling for rain on sunday, which
could play some tricks on us if the window is dripping with rain all day
long.  As the rain interferes with light flowing through the pinhole,
there is no way to anticipapete how the image will ultimately shape up
on the emulsion.  To make things more difficult, low ligh levels
associated with rain may require inordinate exposure times becaue paper
has huge reciprocity errors beyond 60 minutes exposure times.  At 60
minutes, the reciprocity correction factor is 9.5 for a corrected
exposure time of 9 1/2 hrs...

We'll be using 3 strips of 50'' x 98'' to make the print (it'll be paper
negative which will be subsequently contact printed into a paper
positive).  The paper will be tacked on a frame 150'' x 98'' held
vertical with two autopoles.

To get the maximum view of the cityscape, we'll be working with a very
short focal length (so to speak for those not accustomed to large
format).  The focal length will be somewhere between 36'' and 48'', to
be finalized on site.  Optimum pinhole size for a 36'' focal is 1.27 mm
which gives us an F/stop of F/720.  This is quite manageable on a bright
sunny day (6 1/2 minutes, uncorrected for reciprocity), but on a rainy
day, this could well rise to 2hrs. Add reciprocity, the theoretical
exposure time jumps to 26hrs...  -:(

The shutter will be opened at exactly 00:00hr on sunday, April 28, to
celebrate the 2nd Worlwide Pinhole Photography Day and we will let
exposure run until Midnight excatly.  It'll be a 24hr exposure, but my
tests in the past few days indicate that not much of the night time
exposure will show up on paper (unless we were to use a larger pinhole
for night time).

The plan is to have a bunch of 8x10 sheets attached to the side of the
frame and to process one every hour or so to check how the image build
up and to modulate exposure as the image builds up until completion.  On
a bright sunny day, this should occur around noon time, but if it's
rainy, we may barely have enough of the whole day.

We'll be spending mosy of the day today setting up the room, the pinhole
and the wood frame and we should be ready well in time for 00:00hr
tonight.  Exposure will take place all day sunday and we'll start
processing the long strips of paper monday evening and continuing  the
subsequent two evenings.  We'll use large 50'' x 10" tanks made from
boxes used to store rolls of photographic paper, lined up with heavy
plastic.  The tricky part will be the washing stage, to ensure
satisfactory washing.

We'll that's it folks.  I hear that the team doing the Great Wall of
China giant pinhole will have something like 130 people.  Hmmm... A lot
more than the five of us in this project!   -:))

If you want more information, go to
http://www.zeroimage.com/Guy/PinholeHotel.html
or check the reference on the site of Pinhole Visions at
http://www.pinholevisions.org/

Happy pinhole day to all,

Guy