hould be is obviously
determined by the diameter of the piece. The next operation is to
lighten or draw the part, line or streak thus dark colored, causing it
to get paler and paler as it approaches the axial line of the piece or
cylinder. This lightening is accomplished as follows: The dark streak is
applied along such a length of the piece that it will not dry before
there has been time to draw it out or lighten it on the side towards the
axis. A separate brush may then be wetted and drawn along the edge of
the dark streak in short strokes, causing the color to run outwards and
become lighter as it approaches the axis. It will be found that during
this process the brush will occasionally require washing in water,
because from continuous contact with the dark streak the tint it
contains will darken. When the first coat has been laid and spread or
drawn out from end to end of the piece, the process may be repeated two
or three times, the most even results being obtained by making the first
dark streak not too dark, and going over the drawing several times, but
allowing the paper to get very nearly dry between each coat. In small
cylindrical bodies, as, say 1/4 inch in diameter, the darkest line of
shadow may be located at the lines representing the diameter of the
piece, but in pieces of larger diameter the darkest line may be located
at a short distance from the line that denotes the diameter or perimeter
on the shadow or right-hand side of the piece, as is shown in many of
the engravings that follow. It is obvious that if a drawing is to have
dimensions marked on it, the coloring or tinting should not be deep
enough to make it difficult to see the dimension figures.

The size of the brush to be used depends, of course, upon the size of
the piece to be shaded or colored, and it is best to keep one brush for
the dark tint and to never let the brush dry with the tint in it, as
this makes it harsh. In a good brush the hairs are fine, lie close
together when moistened, are smooth and yet sufficiently stiff or
elastic to bend back slightly when the pressure is removed. If, when
under pressure and nearly dry, the hairs will separate or the brush has
no elasticity in it, good results cannot be obtained. All brushes should
be well dried after use.

The light in shading is supposed to come in at the left-hand corner of
the drawing, as was explained with reference to the shade line.

Excellent examples to copy and shade with t