This requires that the engraver must protect the different portions of the zinc plate by a paintlike covering, and this must be done for each of the different kinds of shading used. It is almost impossible to make any square-inch price rate for Ben Day work because each new plate is a problem in itself. The work is ordinarily charged for on a time basis, the usual rates being from $1.00 to $1.50 per hour.

When copy to receive Ben Day work is sent to the engraver it is marked somewhat as shown in Fig. 233, so that the instructions to the engraver may be explicit. Crayon marks specify by number the kind of Ben Day shading desired, and arrows point to the different areas to be shaded. This marking of instruction is done with a blue

GRAPHIC METHODS

pencil because blue does not photograph easily and has such a small eflfect on a photographic plate that it does not spoil the copy for making a good zinc plate. In order to make the zinc plate from which Fig. 233 was actually printed, a red pencil was used for the bottom portion of the illustration referring to Ben Day work. Red photographs as black, and a zinc plate was obtained which shows the marking such as would be used with a blue pencil when Ben Day work is ordered from an engraver. Ben Day work has been used on a great many illustrations in this book, and it is believed that the reader will have no difficulty in distinguishing the cuts with Ben Day work from those cuts for which hand shading was used.