A water-metachromatic sheet has a support with a porous layer containing a binder
resin with dispersed fine-particle silicic acid. The sheet is capable of rendering
different transparency between water absorbed and unabsorbed states. The support
is a cloth having a weight per unit area of 30 gm2 to 1,000 gm2,
the fine-particle silicic acid is contained in an amount of from 1 gm2 to
30 gm2, and the fine-particle silicic acid is incorporated in an amount
from 0.5 to 2 parts by weight based on 1 part by weight of the binder resin.