vj PREFACE

include panels, canvas, paper, and even the masonry of walls. The
word, inert, is still strange to the artist-painter but has a common
application in industrial painting to materials mixed with a medium,
as is a pigment, but which, unlike pigments, have little or no tinting
or hiding power.
In a broad sense, these data were put together for workers in the
art of painting, for all who do work in the art—painters, teachers of
painting, students, museum curators and conservators, paint chemists,
and analysts. There is much that will concern the museum worker
and the paint analyst more than others—distinctions among chemical
and physical properties, problems of conservation, and history of
materials. These details, however, may be of some interest to painters,
and surely they will have a value for students and teachers. Because
this encyclopaedia is for those who work in the arts, the information
has been made selective rather than exhaustive. Many more materials
could have been listed if the aim had been to produce a thorough,
scientific compilation* As it is, most artists will find here facts about
materials that are not familiar to them and that they may never use.
Yet each entry may have its practical worth in the problem of some
painter or worker with paint at some time in his professional life. It
is only hoped that omissions are not too many. Facts about materials
have to be put in the terms in which such facts have their most exact
meaning. Often that requires using the terms of chemistry and physics,
and for the artist who finds these baffling a short glossary has been
added for the purpose of defining some of them.
Recent years have seen an increase in demand on the part of
painters for more information about materials they use, and as this
demand can be satisfied the art will be* enriched. With a wider range
of technical means, a wider scope of expression will become possible.
Many excellent publications have led in that direction. This one is
added not to take the place of any others but to take a somewhat
different place and one that has not been filled*
Much of the work of collecting this information was made possible
by grants for research by the Carnegie Corporation. - Revision of the
periodical publication has been done through a gift from Robert
Treat Paine II. This aid is gratefully acknowledged.
CamMlge^ Massachusetts
November ^ 1941