This file should be placed in the same folder as your other PhotoShop drop-ins, and will then appear in the "Other" submenu under "Filters"
This drop-in allows you to convert a grey scale image to iso-brightness contour lines. The dialog allows the user to select the number of contour lines (from 1 to 9) which are equally spaced in brightness from 0 to 255, and whether the contour lines are to be drawn as the corresponding grey values or not, and on a white or dark background. After the filter has been run by selection from the "Other" submenu, and the dialog selections made, repeating it by selecting Command-F will use the same dialog selections. To change these, you must again select Contour from the submenu.
These filters are described in J. C. Russ "The Image Processing Handbook" CRC Press, Boca Raton, FL (1992). The program is Copyright ゥ 1992 by J. C. & J. C. Russ. It may be distributed at no charge provided the copyright notice accompanies the file.