Colors should be applied to black and white drawings after they are photocopied unless the cost of color printing is no object. The flexible kind can be used for line work. The standard kind is perfect for bar graphs and histograms, for borders, and as leaders from one element of the poster to another. Colored stick-on dots, squares, and triangles are available in various sizes. These prints have colors the reverse of what were used on the original drawing.
White background becomes black, black lines become white, red becomes blue, etc.
A chart showing original colors to use to obtain the desired reverse may be acquired from some photographic studios, or advice may be sought from drafting shops or colleagues experienced in drafting for reverse-color prints or slides. A computer is an excellent tool for preparing text material for posters. However, standard computer printouts are poor material for posters. The standard type size is too small and the line weight is too thin. If printouts must be used, enlargement can improve legibility of tabular material, and addition of color and enhancement of lines with stick-on tape can enliven graphics.