Finding the exposure and development for PERFECT BLACK can be as simple as making a test print of a blank strip of negative material placed on a sheet of the photographic printing paper to be used. Since black is printed for areas of the negative that have no ink, this test can proceed before any others.

When the lighter area, exposed through the negative material just disappears, the proper exposure and development have been found to insure that the areas of your image with a Photoshop value of zero will print as the MAXIMUM BLACK of which the paper and developer are capable.

.In this example, the 7th step is full black. Additional tests might find an intermediate exposure between the 6th and 7th step which first produces black. One should also verify that additional development will not darken the test area.

Whereas with photographic film, the "film base plus fog" can vary from roll to roll and film to film, this is not the case if you use the same material for all of your negatives. The exposure and development values established here will remain valid as long as the same materials are used throughout.

The procedure above will assure PERFECT BLACK, but makes no guarantees for the critical shades between 90% and 100% black. To assure that a Photoshop value of 5 (98% black) can be clearly distinguished from PERFECT BLACK, a test chart will be of value. The chart shown below will be used to establish the contrast which provides PERFECT WHITE, and will help here to prevent excessive exposure and/or development when searching for PERFECT BLACK.

Create a Test Image for use in the calibration process.

The high value band (0, 2, 4, 6, 8, and 10% black), and low value band (90, 92, 94, 96, 98, and 100% black) should be clearly visible in the final print, and constitute a check on the printable tonal RANGE of the negative. In the center, are a black column and a white column.

After the negative has been printed, a strip in the middle of the white column (dense in the negative) is covered with an opaque tape, while a strip in the middle of the black column (no density in the negative) is cut away. In the final silver contact print, the entire "black band" should be black, and, as we shall see in Step 2, the entire "white band" should be white and with good tonality in both the high and low value scales. The final silver print should look like the source document. You may download the source image at the left by performing a "Save AS" on the image at the right, and resizeing it to the size desired. - But be sure NOT to resample when changing the size or you will create fuzzy edges.

Using the chart above to find the exposure needed for PERFECT BLACK, the fully developed contact test strip of the test chart above will look like this. The exposure time at which the black band created by the cutout area is no longer identifiable is that which should be used in all subsequent experiments and production. This is the basic exposure time for MAXIMUM BLACK with the chosen - materials exposure light intensity and color developer and development time Change any, and the value of BLACK will change!

To assure that the light intensity with my Beseler 23CII Dual Dichro enlarger, is the same for EACH EXPOSURE, I use an Ilford EM10, which has the adjustment dial taped at the setting established during the calibration process. After allowing the enlarger light to somewhat stabilize (a rather indeterminate time), I raise and lower the enlarger head until both the green and "high" red light are illuminated. This is a very narrow range and assures maximum repeatability. In fact, the light in my enlarger is so unstable that the best I can get is to have both lights flicker back and forth during the exposure. For the materials described here, I find a 37 second exposure is very close for an EM10 setting of 16. DO NOT assume that once set, the enlarger illumination will remain stable. Mine changes VERY quickly! I have chosen to -

1. place the printing frame on the easel
2. cover it with a black plastic sheet from a paper package
3. turn on the enlarger light source
4. raise or lower the head until BOTH the high-red and green lights on the EM 10 flicker on
5. quickly turn off the enlarger light source
6. quickly remove the black sheet
7. expose with the timer.

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