228 
PAINTING SLIDES FOR THE MICROSCOPE. 
Oct., 1890. 
look very well, and the method is only to be recommended if your 
designs have a simple outline. All my pictures have intricate 
outlines; it is impossible to keep the varnish within these, 
and so I varnish the slide all over. But in varnishing 
the slide all over, the use of the brush is impossible, 
because the brush marks show. You must pour the 
varnish on, as photographers varnish negatives. But I 
do not like spirit varnishes. I prefer a resinous varnish, and 
after trying several sorts I have fixed on Windsor and Newton’s 
mastic picture varnish. It is dear, but a Is. 6d. bottle goes a 
long way. Itis just of the right consistency, and it is perfectly 
clear. When the slide is finished I warm it thoroughly in 
order to dry the paint completely, because watei colours get 
slack and absorb moisture, and so prevent the varnish drying 
properly. Then with a stiff brush I carefully remove every 
speck of dust from the surface of the slide ; now I pour on the 
varnish and drain it off. I do nut slant the slide backwards 
and forwards as is generally recommended, because this makes 
the varnish dry with waves in it, which show on the screen, 
but I lean the slide against something until it is dry. It is 
then finished all but covering. You must be careful to 
keep the cover glass from touching the varnished surface of 
the slide, or it will adhere, and so a little piece of card, about 
as thick as a post card, must be put at each corner of the 
slide, in addition to a suitable “ mask,” to keep the two 
glasses apart. My binding papers I generally make very 
broad, and cut out afterwards all that overlaps the picture. 
Then they do not annoy one by coming off so much. 
As this method of painting slides is equally applicable to 
views and figures, I may give one or two hints about these, 
too. Provided your artistic skill is equal to the demand on 
it, slides made in this way look better than the ordinary 
coloured photograph for the reasons before explained. Figures 
without backgrounds, just as one paints scientific diagrams, 
look very well. The faces are hard to do ; for these I use 
rose-madder mixed with burnt sienna for the flesh tint, and 
putin the details with crimson lake and sepia or black. Faces 
must be worked over a good deal to get the shading right; and 
to do this the paint can be kept moist by breathing on it. 
The high lights of the hair can be picked out with a needle 
point. Landscapes with trees require care, because of the 
green paint, which does not always look the same on the 
screen as when you see it on the slide. Blue skies, with light 
fleecy clouds, can be readily made—if you understand paint¬ 
ing skies—in the following way :—After your outline is 
finished, paint over all the sky with Prussian blue. Lay it 
