Photographer's Non-toxic Pinhole
It actually works. Here's proof.
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The Frugal Photographer's Non-toxic Pinhole Camera Developer
Devised as a fun, safe, inexpensive, yet highly useful developer suitable for science fair projects and pinhole camera experiments.
With this developer, you
should give your film two to four times the normal exposure. For
example, expose ISO 400 film as though it were ISO 100.
Many substances can develop silver-halide films, including cola drinks, tea, coffee, red wine, human urine, and common kitchen and laundry materials. They are not in regular use for many reasons, some of which are obvious, but primarily because they are time-consuming, inefficient, and typically yield high-fog, low-density, unpredictable results.
To develop films, these substances must be mixed into water and the solution made alkaline. The alkalinity activates the otherwise inactive developer. The degree of alkalinity affects development speed and overall image contrast. Unfortunately, most simple "kitchen cupboard" developers require strong, caustic alkalis such as household lye or drain cleaner (both of which are dangerous for children to handle), and they require development times of about a half hour, sometimes much longer.
Here we present a seemingly simple formula that is actually quite sophisticated.
It combines two non-toxic developers, coffee and vitamin C, each of which is a weak and inefficient developer by itself, but which are "super-additive" with each other. That means, when they are combined, the combination is substantially more active than the sum of its ingredients.
It uses a relatively common laundry ingredient, washing soda, which is a mild alkali, as its activator.
This developer creates more background density ("fog") than commercial developers. However, the density is easily dealt with in printing or scanning, and can be ignored.
Because it is non-toxic and does not use caustic alkalis, young children can safely experiment with it, as long as they are careful to not drink it, since it would undoubtedly make them sick. And keep it out of your eyes!
Instant coffee is preferred to brewed coffee only because it is easier to use, and is more likely to be of uniform strength from one batch to the next. There is no reason you couldn't experiment with brewed coffee. Vitamin C crystals are preferred to tablets, since tablets include inert binder that must be filtered out. Citrus juice has too little ascorbic acid to be useful (one cup of orange juice from concentrate contains only about 1/10 of a gram of ascorbic acid).
Caution: this mixture has a revolting burnt-coffee smell. It stains film brown, but the stain washes out during the final wash step..
This formula is presented with rough, whole-number teaspoon measures, because it is not possible to know in advance the potency and activity of ingredients sourced from a supermarket shelf. You should probably experiment with varying amounts of coffee. Keep the ratio of coffee to vitamin C at roughly 1:1 to 1:1.25, by weight, or about 4:1 by volume.
You should definitely experiment with development times. Shoot a roll of black and white film outdoors, with every frame showing the same scene at the same exposure. In the dark, cut the roll into six more or less equal strips, excluding the tongue. Develop one strip for, say, fifteen minutes, and after it has been fixed, washed, and dried, examine it. Wet film looks considerably different from dry film, so be sure you examine it after it has dried. You should be able to guess whether to develop the next strip for a longer or shorter time. After you've developed and evaluated several, you should have a good idea of the proper development time.
This formula should give you excellent, printable images with just about any brand of instant coffee crystals. Play with it for a while, and be prepared to be amazed.
You may be interested in the original Shutterbug Magazine article that provoked these experiments, which is on-line at: http://www.photoglass.com/PHG/PVT/SBug.htm. Please note: The article implies that salt water can be used as a fixer. In fact, fixing in anything other than thiosulfate is impractical. Fortunately, sodium thiosulfate can be bought cheaply from pool supply companies, who sell it as a chlorine reducer. Another resource, not on-line unfortunately, is "That Last Cup of Coffee," page 35 of Darkroom & Creative Camera Techniques, Sept/Oct 1995 issue.
|Tap water at room temperature||1 quart (or 1 litre)|
|Washing soda (sodium
Arm and Hammer brand washing soda is available in many larger supermarkets. Sodium carbonate is also sold by pool supply companies as a pH modifier. Baking soda (sodium bicarbonate) will not work.
|10 level tsp (or approx. 55 to 60 grams)|
|Instant coffee crystals (buy the cheapest, and experiment). I find Maxwell House brand works well and has relatively little odor.||4 level tsp (or 4 to 5 grams)|
|Vitamin C crystals (ascorbic
Buy crystals from a health-food store. If crystals are not available, try crushing vitamin C tablets having the equivalent of 3 to 4 grams of ascorbic acid. 4 1000-mg tablets equals 4 grams. Filter the solution through a coffee filter to remove inert binder. Sodium Ascorbate from the health-food store will also work.
|1 level tsp (or 3 to 4 grams)|
|As you can see,
precise measurements of ingredients is not an issue. In
practical darkroom work, as opposed to scientific research, it is almost
important to measure consistently from one batch to the next than it is
to measure out precisely what a formula calls for.
Add the ingredients to the water in the order shown, dissolving each completely before adding the next.
The washing soda may be perfumed, and it will probably form a cloudy, somewhat gritty mixture that requires several minutes of stirring. Neither matters. If it bothers you, filter it through a coffee filter.
If your solution fills with fine bubbles, they should be allowed to dissipate before developing film.
This mixture retains its power to develop film for at least 24 hours, even when exposed to air. However, to be safe, you should probably only use it when it's relatively fresh. It would be worthwhile experimenting to discover exactly how it changes with age.
Developing times vary according to the film you use, and you should experiment with times between about 12 and 18 minutes. I like 15 minutes as a starting point. Agitate 30 seconds initially, then 10 seconds each minute thereafter.
If, after 15 to 18 minutes of development, your images are not dense enough, that indicates you've given the film too little exposure.
Stop bath: in the spirit of low-cost photography, use a plain water rinse, at least thirty seconds, with agitation. However, adding white household vinegar or powdered citric acid to the water will neutralize the developer more or less instantly, making consistent development easier to achieve and preventing carry-over of developer into your fixer, which will make your fixer last longer. Calculate the amount of vinegar or citric acid to add so that the stop bath contains about 1% acid. Household vinegar is typically about 5% acetic acid, so use about five times as much water as vinegar to get the proportions about right. Too little acid is preferable to too much.
Fixer: Sodium thiosulfate crystals are available from pool supply companies, or from many old-fashioned camera stores. People with swimming pools use it to control excess chlorine.
NEW — thiosulfate fixer is now available from The Frugal Photographer. Click here.
Dissolve 4 level teaspoons of thiosulfate in 4 cups of water. This is a non-hardening fixer and it may leave your film's emulsion prone to damage while wet, so be careful how you handle wet film. It will also not have as long a working life as commercial fixers, which contain buffers and preservatives.
Fix thin films (such as Bluefire Police) for three minutes, and ordinary films for at least five minutes. A rule of thumb is to fix film for twice as long as it takes for the film to lose its initial cloudiness and become clear. The cloudy appearance is caused by the presence of undeveloped silver compound — this undeveloped compound is removed by the fixer. Fixing for twice the clearing time guarantees that all traces of undeveloped silver are removed.
Wash for ten to thirty minutes or more in running water. Ten minutes is usually sufficient. More than thirty minutes is overkill. To conserve water, wash in consecutive baths of plain water, agitating continuously for at least one or two minutes per bath. Click here to read some information on this important step.
Shake off, or very gently blot away, any water droplets that adhere to the film, being very careful to not scratch the emulsion, which will probably be delicate in its wet state. Dry the film by hanging it in a dust-free place where the air is still.
This is the only specialized equipment you need:
Compact Developing tank with two spiral reels, light-tight lid for rotary agitation, liquid-tight lid for inversion or rolling agitation, and instructions. Chemical-resistant plastic. Process color or black and white film, 35mm, 126, 127, 120, 620, and 220.
You don't actually need this tank. Any light-tight container (such as a coffee can covered with aluminum foil) will work as long as you are in a room that can be darkened when you remove the aluminum foil cover to pour chemicals in and out. You can get reasonable results by simply placing the film in the coffee can and sloshing it around. However, you can get perfect results with a proper film-holding reel.