migrated article: “Pintoid” Camera /Film Processor
“Pintoid” Camera /Film Processor
by Jonathan King
Altoid tin pinhole cameras
Altoid pinhole cameras, or “Pintoids”, have been covered on the internet on
web sites (see links) and in discussion groups. When I saw this described, I was intrigued – I’ve made a couple of pinhole cameras in the past, and found that the inexactness of the camera just lets the fun and joy of image making to dominate.
A Pintoid by itself is a fun project, but it seemed that the next step would be to turn the camera into a self contained processor as well!
Processing the film in the camera eliminates most of the film handling, makes daylight processing easy, and has the advantage of keeping the procedure simple for someone who is not familiar with black and white processing. I’ve built pinhole cameras with a group of 10 year old kids. It worked and they were excited, but I didn’t feel it gave them as good an introduction to the ‘magic’ of black and white photography as it could have.
Most Pintoid users have used 35mm film, but I really didn’t like the idea of
cutting, handling, and processing small strips of film. I noticed that the Altoid tin is just about the size of 2 ¼ x 3 ¼ sheet film. J&C Photography stocks Efke 100 film. It turns out that the 2 ¼ x 3 ¼ film fits the Altoid tin quite well. In fact, the film corners catch the tin corners such that there is a spring force that holds the film in place without tape! With normal handling, I haven’t had any film shifting.
There is actually a good deal of preliminary work before camera construction can begin. Most of my Pintoids are Licorice
Start by drilling a hole about 1/8” (about 3mm) in diameter just under the cross bar of the “T” in “ALTOIDS”. The exact diameter is not important. A coat of primer then flat black paint on the inside will reduce reflections and protects the tin from the processing chemicals if you make the processor version (Yes, they do attack the tin). I used spray paint from the local hardware store.
I have a pinhole that I bought (Lenox laser), but I usually make them. I mount the pinhole in the tin with black bookbinding tape that I got for repairing some film holders. Any strong tape should work just as well. I make a shutter from a combination of the bookbinder tape and black electrical tape. Cover the hinges with tape to prevent light leakage. I used the same book binder tape, but anything opaque and sticky should work.
There are many ways to make pinholes, but I’ve found this one easy and quick. I’ve used aluminum cans and brass shim material. If you use aluminum cans, make sure to sand off the paint exterior and the plastic coating on the inside.
I’ve make pinholes with pins and tiny drill bits, pushing or drilling through the metal, but I get better results, especially for smaller pinholes, by just dimpling the metal with a pin, then sanding the dimple open. I start with 600 grit sandpaper and progress to 1500 grit, the finest I can get at locally.
I check the pinhole diameter and roundness with my scanner by scanning at the maximum resolution and checking for burrs or other imperfections.
I normally make several pinholes at once on a single piece of metal and then cut out the ones I want to use. It is easy to adjust your technique to make larger or smaller pinholes, depending on what you are looking for.
The Pintoid processor is a modification of the Pintoid that will let you process the film in the camera without a darkroom! After a bit of searching, I found inserts for compression fittings in the plumbing area of the hardware store. They are a short copper pipe with a flange on one end. I use a ¼ inch fitting.
I found a location of the side of the tin that was as high as possible without interfering with the lid. For the fitting I used, a ¼” diameter hole let the pipe through, but not the flange. I then soldered the insert to the tin. A soldering iron used for electronics worked, but took a minute or two for a well wetted joint. I didn’t have enough finesse to use a plumbing torch – I just charred the Altoids tin
For a hose, I use a thin ¼” O.D. tubing. The second best tubing I found was heat shrink tubing, shrunk and clamped to minimize any chemical leakage. A large paper clip clamped the free end of the tubing, preventing light and chemical leakage, and the camera/processor is done!
While it is possible to pour and drain developer, stop bath and fixer through
the tubing, a monobath developer would be much more convenient.
Monobath developing is a technique sometimes used in the past for press
photography to minimize processing time was a quick development in a
monobath – a combined developer and fixer. Given enough time, the fixer will remove all silver salts, exposed and unexposed. The trick is to have the developer convert the latent image to metallic silver before the fixer goes too far in removing the silver salts.
Most formulas are several decades old from when this technique was in wider use, but a modern formula (from Donald Qualls, via www.photo.net) is made with currently available photo and household chemicals.
Qualls Monobath formula
Kodak HC110 film developer
concentrate (U.S. version) 16ml
Ilford Rapid fix 10ml
Household Ammonia 50ml
Water to 250ml
Process for 7-10 minutes at 68F. Agitate continuously for the first minute, then 10 seconds each 30 seconds. This is more agitation than is normally used, but it is important to quickly develop the image before the fixer removes it.
After processing, open the camera and wash the film. The antihalation backing might not be totally removed. Extra fixing or washing in a solution of 1t sodium carbonate (washing soda) or just water may complete clearing the backing. Use whichever works best for you.
The volume of the Altoid tin is about 90ml. If filled, the hinge will leak, so a
practical maximum volume is about 40ml. I’ve successfully used volumes
between 25ml and 40ml.
Film speed can be a stop or two less in a monobath developer, so I started
rating the Efke 100 film at E.I. 25. The pinholes I use have an f-stop of about f/64 so exposure times quickly got into reciprocity failure, requiring even longer exposures. Full sun exposures were about 1 second, while indoor scenes or were 15 minutes to an hour.
I added a few construction photos, and a quick image, just to prove it works . Of course, being December, daylight hours are short and work-filled, and the weekends have been gray, so my office is what you get!
Links: Marcy Merrill’s Pintoid site: http://www.merrillphoto.com/pintoids.htm
Pinhole Designer program (free!, Windows only): http://www.pinhole.cz
Pinhole Calculation site: http://www.mrpinhole.com