The use of contour plots to optimize exposure and development time in the preparation of color correction masks with a three-aim-point control system

The calculation of optimum development and exposure for color separation mask has long been a problem for the color separator. Today this problem is somewhat minimized through the use of mini-computers which utilize mathemati cal models in their programming. This thesis examines an alternative method of solving for optimum development speed and exposure conditions. The alternative tested was the use of contour plotting to predict a development and exposure time which would yield a predetermined mask number and A-B range. The process which the tests were conducted against was silver masking using three-aim-point control in contact conditions. This thesis describes in detail a simple step-by- step method to sample, record, and plot contour curves for given sets of mask numbers and A-B ranges. When completed, these plots or graphs literally provide a map whereby the user can reasonably predict the results of his future mask -making attempts. This method was tested by students during a summer class in Advanced Color Reproduction at the Rochester Institute of Technology. The students were able to perform the darkroom work, measure resulting mask values, and complete the plotting of curves with only a few hours of instruction. Upon completion of the contours, they evaluated them for accuracy of predictability. The positive results of those tests are presented in this thesis