After a photograph has been made of the pin map it is best to compare the photograph with the original, and then to make squares out of those circles which represent a certain color of pin on the original map. Squares are easily made by using a fine pen on a photograph considerably larger than the cut itself will be. When the final dots are not too small in size it is possible to make shapes with the pen such as triangles, outline circles, etc., which can be distinguished from one another.

If a great reduction in size is necessary between the original material and the finished illustration, extreme care must be used to have all the lines on any original drawing wide enough to stand the reduction in line thickness due to the decrease in size. If a drawing one foot wide is photographed down to an illustration three inches wide the lines will be only one-quarter as thick as in the original drawing. Lines on the original drawing must therefore be made very wide -- in fact, much wider than is ordinarily considered desirable until experience has been gained from several disappointments in the appearance of finished illustrations. It is not easy to find maps with lines sufficiently heavy to permit of the great photographic reduction usually necessary in making illustrations from pin maps or other map representations. Quite often it is necessary for the person making a map chart to go over by hand all outlines such as borders and the divisions between States, counties, etc., to make those particular lines very much heavier than on any map which can be purchased.