As the proliferation of technology continues to force its way into our lives, the hobby of producing images through photographic means has followed suit. Every aspect, from the exposure of film, through print production, has offered the photographer the ability to lose control of the art form. Whereas this may increase production, one wonders who should actually be allowed to sign the final product.
As a means of reversing this tendency in my own work, I decided to take complete control of as many aspects as I felt technically feasible. This sent me in two directions: expose the negative, not with an expensive automatic-everything camera, but with a pinhole camera, and create the print, not with commercially-produced paper, but coat my own and print using the sun. Stone knives and bear skins.
In this article I suggest that looking backward, when everyone else is looking forward, may be a consideration not only for contrarians, but also for those who wish to separate themselves from the field. Do I suggest tossing our cameras and paper away to follow this path? I would no more do so than suggest one remain using a single film, paper, and set of chemicals. This is a direction, a means of extending oneself, a way of improving other aspects of one’s photography by seeking another posture.
Part I - Stone Knives
Pinhole takes us to the very essence of photography. At this level, depth of field no longer has meaning, captured light strikes the film plane without the intervention of any modifying factors, and the creation of the tool can be done entirely with materials one already owns. Doing this, we are separated from the mainstream and have the capability to create unique images. Is this not what artists aspire to obtain?
Pinhole photography returns us, perhaps, to the very beginning of photography (it is possible that the first photograph by Niépce in 1826, an eight hour exposure, was a pinhole image). Of course, this idea has been around considerably longer. Ibn al-Haitham (965-1039 AD) wrote of the use of the pinhole to study light rays, Theodoric of Freiberg and Kamal al-Din al-Farisi (14th century) independently used the pinhole to explain the rainbow’s color principals, and some Italian cathedrals in the 15th century contained a pinhole in the ceiling to tell the time. The first use of the camera obscura (a term coined by the astronomer Johannes Kepler) was used by Gemma Frisius to study the solar eclipse of 1544.
The basics of pinhole photography is very simple. Light enters a light-tight box through a very small, lensless aperture, striking the film. If this was the only principle involved, could increase the sharpness of the resultant image by reducing the size of the aperture. However, another element, diffraction, comes into play. This was first demonstrated by the Italian physicist, Francesco Grimaldi, in 1665, where light passing through two consecutive pinholes displayed wider than it should have. The smaller hole, therefore, will increase diffraction, working against the image’s sharpness. The photographer working to obtain the sharpest possible image needs to find a balance between these two conditions.
In addition to this diffraction, it was noted that the boundaries showed coloration. The wave theory indicates that the wavelength is a determining factor of the resulting diffraction -- the longer the wavelength, the greater the diffraction. As the red end of the visible spectrum has a greater wavelength than the purple, it is diffracted more, and will show on the outer boundaries.
The nuts and bolts of pinhole photography can be as extravagant, or plain, as complex or simple, as imaginative or straightforward as one may wish. A good starting point is to determine how to make the hole and how large it should be. The instructions I will give have yielded for me quality round pinholes that yield a surprising sharpness. Certainly, if one wishes to work for a less sharp image, simply deviate from the suggested size or roundness of the hole.
There is no consensus as to exactly which proposed formula will actually yield the aperture value for optimum pinhole size. I have relied on the following formula primarily because of its simplicity.
A = square root of 55 * F, where A is the aperture in thousandths of an inch and F is the focal length in inches.
For instance, if your focal length is 10", the square root of 10 * 55 is 23.45 thousandths of an inch. It is best to convert this to millimeters, as I will explain, so our final value is 0.02345 * 25.4, or .59mm.
The material for creating the pinhole can be anything thin and easy to work with, and I have found aluminum pie pans to work nicely. Cut 1" X 1.5" strip and tape it onto a surface. Break a sewing needle in half and shove the blunt end into a pencil eraser. Place the sharp end of the pin in the middle of the aluminum and gently rotate the pencil, barely exerting pressure. Soon, you can remove the needle and find that a hole has been formed. Remove the tape, turn the aluminum over, and use very fine sandpaper to very gently sand the back side of the hole in a circular manner. Place the aluminum in a glassless slide mount. This makes the pinhole a bit more resistant to damage, as well as giving you a place to put notes, like the size of the hole. Voila -- a pinhole.
Determining the size of the pinhole is no problem. Raise the negative carrier of your enlarger and focus to the point where 1" in the carrier will be displayed as 10" on the board (note: your 35mm carrier may not be 1" wide, so carefully measure before determining that you have set the proper height). Place the slide in the negative carrier and turn on the enlarger lamp. The projected light will display the hole ten times larger. Place a ruler with a metric scale underneath and examine with a magnifying glass to determine the size of the hole.
I would suggest creating several pinholes and writing their sizes on the slide mount. You can then construct your camera to the focal length of the pinhole. Of course, if the hole is smaller than you would like, you can repeat the series to create a larger pinhole.
Projecting the hole also allows you to closely examine the quality of the hole. Anything other than a clean circular hole will cause additional diffraction.
When you are satisfied with the hole, place a very small piece of tape over the hole while you spray paint it flat matte black. The box you use should also have been spray painted flat matte black.
Determining exposure is only tricky because we are accustomed to using apertures like f8 and f22. In the above example, the f-stop would be 10" / 0.02345" or f426. Certainly, you will need to understand the reciprocity of the film you will be using when determining the exposure time. As this could well be into the minutes, as opposed to small portions of a second, an accurate shutter will not be necessary.
So there is your stone knife, to use or abuse it as you wish. Next, I suggest the bear skin, the Van Dyke process, for printing your negatives.
Part II - Bear Skins
Now that we have created the negative, we are ready to produce an image that can be framed and mounted on the wall. There are many choices for this process. The typical decision would be to purchase a photographic paper, place it under the lens of your enlarger, expose and develop it. We, however, are searching another direction and will coat our own paper with our own sensitizer, expose it to the sun, and develop it with water. Only the fact that we need to chemically fix the paper is the same.
Why would one go through the bother of coating their own paper? There are numerous reasons, and perhaps one will fit your purpose.
One reason would certainly be that there is a greater range of paper choices. Visiting the local art store, one can find watercolor paper in any finish between glossy and burlap. The choices of paper color is also considerably wider. One can choose anything between stark white through black, as well as checkerboard, dot, and any other pattern you can (or cannot) imagine. Why one would choose a dot pattern is well beyond me, but the possibilities are there.
Also, there is a wide variety of coloration available. Certainly, toning silver gelatin paper offers one alternatives to the standard black color, but with the choice of printing on platinum, Van Dyke, cyanotype, or the new Ziatype, the tonal representation can be perfected.
My reason, however, is that it forces me to slow down. This is certainly a more time-consuming process, and in these days of "need-it-yesterday," a logic such as this might sound nonsensical. However, just as I found that my images improved when I began using a view camera (as opposed to shooting several rolls and hoping a couple would give me what I wanted), coating my own paper drove me to more carefully examining this part of the process.
There are many alternative processes (palladium, kallitype, carbon, gum, etc.) and my choice of Van Dyke did not come by accident. For one thing, many of my images work very nicely when toned with a sepia toner. This made for the choice of process that naturally resulted in a brown tone.
Also, I wanted to work with a process in which few others were involved. Even in the late 19th century, the Van Dyke process enjoyed only a modicum of popularity. Additionally, I wanted something that would give me quality results. I can report that my prints have, at times, been confused with platinum prints. Finally, I wanted something affordable. Van Dyke is one of the least expensive, as well as easiest, of the alternative processes.
The Van Dyke process was patented by W. W. J. Nichol in 1889. Soon after, the formula was modified in many ways to produce variations in the brown color. Numerous formulas exist, and you can play with one of the formulas displayed below.
Van Dyke printing involves the reduction of silver nitrate, with the color resulting from ferric ammonium citrate salts reducing to ferrous iron. The sensitizer may be spread on numerous surfaces, but to date I have only used watercolor paper. You may wish to experiment.
Here is one of many possible formulas
|Ferric Ammonium Citrate||23g|
|Water to make||250ml|
This much sensitizer should be enough to coat around 100 8X10" prints. Oddly, aged formula will yield better results than fresh, though there is a limit. With the first formula I found that I got uneven results after about nine months. Possibly the second formula would have better keeping abilities.
I will put in a short plug for Artcraft Chemicals at this point. Besides being very easy to work with, they are willing to sell small amounts of chemistry to your specifications. This allows one to try out a process such as this with minimal investment. You need not be confined to the restraints of a commercial kit.
When mixing, wear gloves and old clothes. Any clothing stained will bear a permanent scar. Your skin will also show spills as soon as light hits it. You cannot wash this away, and will have to just wait for the natural process of skin shedding to resolve the issue.
I was going to include information at this point on selecting the right paper, but have come to the conclusion that there is no "right" paper. There are many papers that will work very nicely. Fabriano Artistico will work very well, as will papers from Strathmore, Crane and Arches.
You will have a choice between hot press and cold press papers. This is a matter of individual choice, as I have heard from ardent supporters of either side. Hot press papers have a smooth finish, cold press have texture. My personal choice is cold press, as this is something unavailable in the commercially-purchased silver gelatin boxes. Decide for yourself.
There are many ways to apply the sensitizer to the paper. One popular method is to use a glass rod. This works by placing drops of sensitizer in front of a glass rod that has a handle attached, and pushing it across the paper, then back in the other direction. However, for under a dollar you can go to the hardware store and purchase a foam brush that will work just as well. Dip the brush in the sensitizer and spread it on the paper in even strokes. A thin coat should be employed, as a thick coat will give lesser contrast.
As this is a contact printing process, the simplest tact here is to place the negative on the dried paper, then put the two between two sheets of glass and expose it to the sun. When you are convinced that the alternative processes are going to be a serious part of your photographic work, you can invest in a contact printing frame with a split back. This will allow you to check on the process of your exposure without getting the film and paper out of registration.
As this is a long tonal scale process, a negative exhibiting high contrast will work best. When the uncovered part of the paper turns a nice dark brown, it is time to develop the print. For this, the print is placed in a pan of slowly running water for several minutes.
Next, the print needs to be fixed with a sodium thiosulfate mixture. The standard fixing solution involves dissolving 240 grams of sodium thiosulfate in one liter of water. However, a mixture this strong will bleach your print. I suggest 1/10th this amount (24 grams per liter) and fixing for a maximum of two minutes. As soon as the print hits the fixer, the color will take a dramatic change to a darker, richer, lovely brown.
Finally, wash the print. I suggest the use of a wash aid, such as Perma Wash. A final wash need not be as extensive as fiber-based photographic paper, as there is no substrate to fight and the dilution of sodium thiosulfate is greater. I wash my prints for 15 minutes then air dry them.
So there you have it - pinhole and Van Dyke - stone knives and bear skins. How will these affect your photographic vision? If you’ve never tried them, I can guarantee that you will come away with a different perspective on your work. There can only be advantage there.