A couple of weeks ago I came across a formula on line for a developer that intrigued me. This particular formula, called 510 Pyro was developed by a Seattle based photographer named Jay De Fehr. It is a staining developer that uses Pyrogallol as the main developing agent. This chemical is enhanced and made super additive by the addition of Phenidone. The base for this formula is Triethanolamine, and Ascorbic Acid is also added.
I had trouble tracking down a couple of the ingredients for this developer. They are all available out of the United States, but a couple of them can not be shipped internationally. Some of these ingredients are toxic and a certain amount of care is needed in handling them. The restrictions on their shipment come about as a result of the paranoia following the 9-11 terrorist attacks in the United States. Eventually I found a supplier here in Canada that was able to supply these chemicals to me. I ordered them, and they arrived a few days ago. The base, or carrier for this formula is the triethanolamine [or TEA] and it was selected by Jay De Fehr because it does not absorb any oxygen. Once the developing agents have been suspended in solution in this base, they are not exposed to any oxygen and this preserves them and keeps them from breaking down. The other interesting fact about TEA is that it "freezes" and becomes a solid at around 65 degrees F. In consideration of this, and our recent cold weather, it was not a surprise to find that the 4L jug of TEA that I ordered was as hard as a curling rock when it arrived. I had to submerse it in a warm water bath for quite a while to get it to liquefy. Eventually it got to the point that I was able to pour over a small amount to work with. When it actually was time to mix up the formula I used a small warming plate to further liquefy this base and make mixing of the ingredients easier. With this developer finally mixed up and ready to go, I set about testing some film...
I work by a method known as the Zone System. This was pioneered by American Photographer Ansel Adams way back in the 1930's and 1940's. It has since be analyzed, modified, updated and improved by countless other photographers. One that took it to the utmost detail was an another American; Phil Davis. I have read and re-read his book, Beyond the Zone System and tried to understand this very technical method of analyzing and understanding the sensitivity of film. The details of this go way beyond what I can describe in this short post but I will attempt a short summary.
I use a Step Tablet. This is a piece of film that has been exposed to light and processed under very prescribed laboratory conditions. I bought my step table from Kodak, and it was very expensive. Basically each incremental grey step on this scale increases in density by a precise known amount. I expose a piece of the film that I am testing through this step tablet and process it. I know that each step of density increase will be by a set amount. When film is processed it takes a certain amount of time for the developing agent to convert the chemical particles within the emulsion, that have been exposed to light, to metallic silver. Beyond this threshold of development, increasing the development time increases not only the density of the image, but also the contrast. Extended development times have little or no effect on the shadow areas of an image, but the mid-tone and highlight areas of the negative increase in contrast the longer that the film is developed.
The testing procedure basically involves exposing a number of pieces of film, under identical conditions, to the known density values of the step tablet and then processing them for different development times. This requires the placement the step tablet on top of a piece of film and exposing it to light. I also lay a coin on the edge of the sheet of film. This provides me a reference point where I have an area of the film that I know received no exposure. This photograph shows my step tablet taped into a kraft paper carrier. It also shows a developed piece of film that was exposed to light through this step tablet.
I exposed five pieces of film identically, and then developed them for different times. The development times were 4:00 minutes, 5:30 minutes, 8:00 minutes, 11:00 minutes, and 16:00 times. Note that these times increase by a factor of the square root of two, just as aperture numbers on a lens do. Once I had the five sheets of film processed and dried I used an instrument called a densitometer to measure the density of each step of exposure in each piece of film. Here is a photograph of one of the test negatives on my densitometer.
What I found was that the clear areas of the negative, that received very little exposure... the equivalent of the shadow areas in a pictorial image, really didn't change much as development time increased. The denser areas of the negative, that received considerably more exposure... the equivalent of the mid tone and highlight values in a pictorial image, increase rather dramatically in density as development time increased. The more development time given, the greater the density, and the greater the density increase between the steps. With this data I was able to plot some graphs to evaluate the density and contrast increase resulting from the various development times. In the good old days I used to draw these out by hand. Now there is a program available from Phil Davis that just allows me to enter the density values of my test negatives, and it plots all the graphs for me. Here is an example of some of the data generated by this program...
With this one relatively simple [to me...!] test I was able to determine the film speed for proper exposure of the film, based on my development routine in this particular developer. I was also able to determine how long to develop the film when I have a normal brightness range in my subject, in consideration of the lighting conditions at the time I am taking the photograph. I also know how much to increase or decrease development time when I want to increase or decrease contrast, as dictated by the lighting conditions at the time I am exposing the film.
This is the part of traditional film based photography that I love. The hands on aspect of mixing my own chemistry and establishing my own working criteria. This is all lost to digital photographers who simply go out and "capture" thousands of images, then invest significant time in becoming an editor, to select the best ones, and then invest further time to sit at a monitor and manipulate and refine the image to what they like. I do exactly the same thing, and invest probably just as much time, but I do it by a much more hands on method. I just find it much more relaxing and enjoyable to spend time down in my darkroom, doing things with my hands, with music playing in the background, and mentally needing to comprehend and grasp the reality of what I am doing. The alternative, to sit in front of a monitor, clicking on a mouse, and letting the predefined parameters of a software program decide how my image will look, simply does not appeal to me.
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