Certain substances like ammonia, potassium bichromate, and acetate of iron, give chemical reactions on certain woods and make very effective and inexpensive stains.

Moreover the artistic effect of some of them is unexcelled.

When applied in solution they are likely to raise the grain.
The effect of ammonia, either the liquid or fumes, is much the same as the effect produced by aging or weathering.

Ammonia also cuts the pith rays of oak and makes it possible for other stains to take hold.
For this reason it is much used as a preliminary treatment for oak finishes.

The color effect is to lessen the yellow and increase the gray.
The method of application is simply to expose the wood for a day or more to the fumes of strong ammonia (28%) in a tightly closed box.