---559023410-851401618-814637741=:1094
Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
Content-ID: <Pine.SOL.3.91.951025121842.1094I@ganges>
As there seems to be sufficient interest, I will post this to all.
I had mentioned in an earlier thread an article in the Pinhole Journal
about processing X-ray film. I have just received a post from the author
of that article, Marnie P. Cardozo, which contains an update of the
information in that article, which I am posting to the group along with
the text of the original article. Please note that I have been given
single-use permission to reproduce the text of this article
electronically in the listserver alt-photo-process; anyone wishing to
reproduce or disseminate this information further should first request
permission from Ms. Cardozo at mcardozo@world.std.edu.
I am currently doing research on lensless photography and
alternative processes for a web page devoted to pinhole cameras.
I have come across a number of articles dealing with X-ray film, which I
am sending as a seperate post.
richard u wheeler (rwheeler@everest.hunter.cuny.edu)
Marnie P. Cardozo. About X-ray film.
Pinhole Journal, Vol.9#3 December 1993.
Reproduced with permission of the author.
Because X-ray film is fast (ASA 800-2400), it has great potential for the
pinhole photographer who likes to shoot indoors with flash. X-ray film
can be exposed with tungsten light, too, but like all orthochromatic
films, it loses 2 stops in speed when it is exposed with tungsten light.
It can be handled under a #1A red safelight. Cut sheets of 8"x10" X-ray
film into sheets 4"x5" to use in 4"x5" cameras or into pieces of other
sizes to accommodate other cameras.
X-ray film is sensitized on both sides, thus encouraging the creative
photographer to adjust his/her view cameras or pinhole cameras to expose
the film on both sides simultaneously. Put the film at the designated
spot in the bellows or body of your camera and expose it with a wide-angle
pinhole/lens at one end of the camera and a telephoto lens/pinhole at the
other. To avoid over-exposing the negative, reduce your exposure time by
half.
If you over expose X-ray film by several stops and develop it for only
15-20 seconds, the emulsion will be so soft you can manipulate it. Hold
the film up by a corner and let the emulsion streak (run) or move the
emulsion around with your finger. Work quickly; the emulsion begins to
set 15-20 seconds after the film has been removed from the developer.
After manipulating the emulsion, process the film normally.
I have worked with only rare earth blue X-ray film. This film has a
pronounced blue film base. However, it prints well on grades #2 and #3
papers. If your X-ray film negatives are too contrasty, reduce the
dilution of the developer 10-15%. X-ray film negatives make lovely
VanDyke brown prints.
Development of rare earth blue X-ray film
1) Set up trays as follow. All chemistries must be 68 [degrees].
a) normal strength all-purpose paper developer
b) normal strength stop-bath
c) film strength fixer with/without hardener
d) wash tray
e) normal strength photoflo
2) Under a #1A red safelight, load film holder with X-ray film. Make the
exposure and unload the film holder.
3) Work with a #1A red safelight in your darkroom. When you are
ready to process the film, quickly slide a 'single' [underlined] sheet of
film into the developer; the film must go into the developer 'all at
once' [underlined]. Agitate the tray-with-film continuously for 1-2
minutes.
4) With your fingers, pick up the sheet of film by a corner and lift it
out of the developer. Transfer it to the stop bath. Agitate the
tray-with-film for 30 seconds.
5) Transfer the sheet of film to the fixer and fix it for at least 1
minute; use constant agitation. Use the manufacturer's directions to
determine the correct fixing time for film. DO NOT under-fix X-ray film!
6) Transfer the sheet of film to the wash tray and wash it for at least
10 minutes.
7) Transfer sheet of film to a tray of photoflo; let it rest in the
photoflo for 1 minute.
8) Remove the sheet of of film from the photoflo and hang it by the
corner to dry. It will be dry in about thirty minutes.
Addendum
Using Rare Earth Blue X-ray Film
in Pinhole Photography
1) Calculating Exposure Times
I continue to think that the exact daylight ASA of rare earth
blue X-ray film cannot be calculated; however, probably its daylight ASA is
800-1600.
To get a meter reading, set an incident light meter as follows.
If you use a reflectance light meter, take your reading from a Zone V
subject (red brick, green grass, asphalt pavement,etc) and use an every
so slightly longer exposure time.
meter settings: ASA (film speed): 100
shutter speed: 1/30 second
If the recommended aperture is f32, exposure time on X-ray film
in a pinhole camera is 3 seconds.
If the recommended aperture is f16, exposure time is 15-30 seconds.
If the recommended aperture is f8, exposure time is 2-3 minutes
or longer.
If the recommended aperture is f4, exposure time on X-ray film is
8 minutes or longer.
These times are a point of departure only. You must determine
for yourself the correct exposure times for X-ray film in your pinhole
cameras.
X-ray film may have a reciprocity failure curve similar that of
other orthochromatic films. I have NOT tested it for this.
If you expose X-ray film with tungsten light, you lose at least 2
stops of speed. Thus, if you meter reading is f16, use the exposure time
for f8, etc. Again, you must determine what works for you and your cameras.
2) Hints on Developing Rare Earth Blue X-ray Film
Kodak recommends that you use a #6B brown safelight when working
with rare earth blue X-ray film. However, you can use a very, very dim
#1A red safelight. To avoid fogging the film, don't expose it to a red
safelight for longer than necessary. Have the light as far away as
possible from your work area.
When you shoot onto X-ray film in sunlight or in other bright
light situations, you may get excessively contrasty negatives. To reduce
nega-tive contrast, dilute the film developer 10-25% more than directed
by the manufacturer. I use Sprint Print Developer diluted 1:10 or 1:11
at 70o for 1 - 1 1/2 minutes. These dilutions and times work well with
Kodak ProMax print developer. Also, you can use low contrast paper
developers such as Kodak Selectol Soft. Use working dilutions of these
developers at 68o with a processing time of 1-3 minutes.
Stop X-ray film for 30 seconds Fix it in hardened film-strength
fixer for 1-2 minutes. Wash the film, one sheet at a time, in a
tray-type washer for 10 minutes and hang it to dry. Photoflo seems not
to be necessary.
3) Hints about Printing Rare Earth Blue X-ray Film Negatives
You may find that prints made from X-ray film negatives are
excessively contrasty. Try one of the following to control the image
contrast.
1) If you are printing X-ray film on warm tone #2 papers, the
image contrast may be fine.
2) If you are printing it on Ilford Multigrate RC Deluxe or RC
III paper, the image contrast may be fine.
3) If you are printing X-ray film on Ilford Multigrade fiber
based paper, you may need to use filtration to adjust the image
contrast. If your enlarger has a dichroic color head, use as your point
of departure 10-60 points of yellow and 10-30 points of magenta. If you
use colored contrast filters, start with a #1 1/2 filter and work down to
#0 as needed. There is no guarantee that this will work but it is worth
a try. Increasing image contrast with magenta filtration does not work
well, if at all.
4) If you are printing X-ray film on graded cold tone papers,
try one of the following.
a) Dilute a working solution of paper developer up to 30% more
than recommended by the manufacturer. Process the print for 2-4 minutes.
b) Use a two-bath print developer such as Dr. Beers or Selectol/
Selectol Soft - or make your own 2-bath developer by having one tray with
dilute developer and one with strong developer. Always immerse the print
in the soft/dilute developer first.
c) To increase highlight detail, use a water bath in conjunction
with the print developer. Do this as follows.
i) Immerse the exposed print in normal strength paper
developer at 68o for 30 seconds; agitate the tray gently.
ii) Remove the print from the developer and let it drain
over the tray for 5 seconds.
iii) Immerse the print in a tray of plain water at 68o
for 15-30 seconds; agitate the tray gently.
iv) Remove the print from the water bath and let it
drain over the tray for 5 seconds.
v) Return the print to the developer for another 30
seconds; agitate the tray gently.
vi) Continue to move the print at 30 second intervals
from the developer to the water bath and back to the developer. Total
processing time is 2 1/2 - 4 minutes. Highlight detail will increase
while the print is in the water bath. Use the water bath 2-3 times
during development. If the print is flat, increase the time it is in
the developer. Experiment to see what works best with your images.
Since water from the water bath dilutes the developer and
developer contaminates the water bath, replace the contents of these
trays every 2-3 prints.
vii) Stop and fix the print normally.
viii) Wash, permawash, and wash the print normally.
X-ray film negatives make wonderful cyanotypes and VanDyke brown
prints. However, they may be too contrasty for gum prints and callitypes.
Marnie Cardozo
copyrighted 1995
---559023410-851401618-814637741=:1094--