Take a print of a human face, with a Rembrandt or Tintoretto effect of
deep shadows and soft lights, and cut out the whole outline and all the
lights, picking with a pin the thin lines and spots. Heads of Christ,
and the Madonna as Our Lady of Sorrows, are excellent, for this purpose.
[Illustration: Fig. 128.]
On holding these up between the white wall and a lighted candle, in a
position found on trial, the figure formed seems to float vaguely
instinct with mournful life, the indistinctness of the outline aiding
the illusion.