se, if you want the work strong, that
you should paint the matt so that it will just yield, and only just, and
that with difficulty, to the scrub; and, before you use this tool, just
pass the finger, lightly, backwards and forwards over the matted
surface. This will take out a shimmer of light here and there, according
to the inequalities of the texture in the glass itself; the first
touches of the scrub will not then look so startling and hard as if
taken out of the dead, even matt; and also this rubbing of the finger
across the surface seems to make the matt yield more easily to the tool.
The dust remaining on the surface perhaps helps this; anyhow, this is as
far as you can go on the side of strength in the work. You can of course
"back" the work, that is, paint on the back as well as the front--a mere
film at the back; but this is a method of a rather doubtful nature. The
pigment on the back does not fire equally well with that on the front,
and when the window is in its place, that side will be, you must bear in
mind, exposed to the weather.

I have spoken incidentally of rubbing the glass with the finger as a
part of painting; but the practice can be carried further and used more
generally than I have yet said: the little "pits" and markings on the
surface of the glass, which I mentioned when I spoke of the "right and
wrong sides" of the material, can be drawn into the service of the
window sometimes with very happy effect. Being treated with matt and
then rubbed with the finger, they often produce very charming varieties
of texture on the glass, which the painter will find many ways of making
useful.

_Of the Second Painting of Glass after it has been Fired._--So far we
have only spoken of the appearance of work after its first fire, and its
influence upon choice of method for _first painting_; but there is of
course the resource which is the proper subject of this chapter, namely,
the second painting.

Very small work can be done with one fire; but only very skilful
painters can get work, on any large scale, strong enough for one fire to
serve, and that only with the use of backing. Of course if very faint
tones of shadow satisfy you, the work can be done with one fire; but if
it is well fired it must almost of necessity be pale. Some people like
it so--it is a matter of taste, and there can be no pronouncement made
about it; but if you wish your work to look strong in light and
shade--stronger than one paint