More on the Test Slides for sheet film testing

I was asked to clarify the diamond patterns on the dark slides when doing the towel test for the film being used. The diamond shape is the one I happened to use as it was the easiest to cut out. Any other shape can be used, such as square, circle or any other. Just remember you have to cut that shape out six times. The size of the cutout can also be enlarged as well. I used that size/shape as it was sufficient for taking a reading from a simple (cheap) densitometer I had at the time. I just wanted to have the densities to see (put up to a light source) and measure to see where the first texture density fell in the frames, and, the second texture density, to see if they were four stops apart.

Densities double each step for the most part. It is when they do not that close attention to said developer or developing time to know why that is, before correcting it. Using the six slides, allows for eight density patterns on one sheet of film. Minimum film and developer use, as well as time. What you are looking for in the densities is when texture first begins to show up. If the film is shot at its posted ISO rating the first density image you see, the thinnest representing pure black in the print, then two frames up from that should show some texture (Zone 3 ~ shadows with detail) then four frames up from that you should see white with texture (Zone 7 ~ white with texture) and the final frame should be pure white.

The only thing that will alter frame one, is to alter the ISO before shooting. If the final frame, pure white, isn't, it calls for more time in the developer, (or less dilution). If the pure white is at frame seven, then the development is too long, (or not diluted enough). This test shows you exactly what your finished prints will look like in tonal scale, on the paper/medium and developer being used. When you change paper, medium, or developer, said original test is no longer valid. It must be done again for each new combination of lens, developer, paper/medium used. Many photographers glaze over when thinking about this, but once you do the first test you realize it isn't difficult at all.

This testing procedure is the baseline for the task of 'pre-visualization", as concept I will bring up once again. Pre-visualization is simply knowing your camera equipment, film, metering and development (after film test) before you click the shutter. You know exactly what you are going to get when you meter for Zone 3 (shadows with detail) or Zone 7 (white with texture). All other densities will fall into  place, with exception to one; Zone 8, which is totally controlled by development time. For the vast majority of cases, if Zone 7 (frame 7) is white, with detail, then Zone 8 will be pure white, as intended for a 'full range' black and white image. Full range representing eight distinct tonal ranges from pure black to pure white.

Another reason to know your density ranges is simple because there will be times when you do not want a full tonal range image, for numerous reasons. Controlling for exactly the tonal range you want, before shooting, is based upon the texture testing. Without that you are merely guessing.

Below is an attempt to show what a finished sheet of cut film might look like after the texture test. The cut sheets with diamond cuts are actually set up to make ten density samples, although only eight are actually needed. The final to density ranges will tell you something about your developer though. I used ten when doing the testing. By using them in the order they are shown, then flipping over the first four sheets, ten samples can be taken, or you can stop at eight.

Cut film after texture text; shown are ten densities on one sheet of film using the dark slides as shown.
The increased density of each density sample on the sheet film can be seen. I have said earlier that there eight densities for the test, which can be done as well. The full ten shots don't take much more time to do but it does give you a good look at how your developer acts with the top densities, which can tell you something about what an expansion might look like in densities. What you are looking for is the two density ranges indicated with an arrow. Those are the two tonal ranges that matter when testing for densities, as well as the final density; zone 8. It should be pure white frame #8.