Final Check

The presence of pure white and pure black can be assessed using the high and low value bands attached to each negative, as described in Step 4, Each print should be evaluated for exposure, development, and contrast. Variability among prints maybe caused by changes in Paper, chemicals, or processing Intensity or color of light source Effective density of the negative due to fading, or drying Without the scales attached to each print, subtile deviations from the optimum will go unnoticed. The most troublesome for me are #2 and #3, light intensity being a continuous problem, and the fading of the negative most noticeable within the first few weeks.

Loss of Contrast Clue: White band has no white, as easily seen against the taped portion, while the low value (black) scale exhibits the expected density. Since the contrast is controlled by both density AND color in the negative, I would be at a loss to know which has caused the loss of "effective density". The most direct fix for this problem is to add a bit of magenta when printing.	Excessive Exposure Clue: Too much density in both the high AND low value scales. If all of the normal procedures have been followed, this is most likely due to an unstable light source and requires checking with a light probe such as the Ilford EM10.

Since the calibration process is usually carried out with negatives that have just been printed, the "effective density" is provided by "fresh" ink. Does the effective density change as the ink dries? It now appears the answer is YES! Prints made with negatives that are 2 to 3 weeks old, exhibit the tonality shown in the "Loss of Contrast" example above. Black is fine, but white is no longer white, indicating that HUE=0 and a Transfer Function setting of 70 does not provide adequate contrast after the negative has aged.

Rather than change the initial negative color, I have chosen to add magenta to the light source, and add exposure time. This means a bit of print testing at each new session, but perhaps the degradation will slow or stop after the first few days.

Start Preparation Step 1 Step 2 Step 3 Step 4 Image Preparation Material Selection Find Minimum Exposure Needed to Print Pure BLACK with the chosen negative material Find Ink Combination for the Proper "Effective Density" to Print Pure White. Create an Adjustment Curve Make a negative

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