Stains are used to tint glazes, slips and clays. Could also be used as a base for decorating colours etc.
Stains could, to some extent, be used as decorating colours, even without additives.

The shade of colour could vary with the use of differently composed glazes. Accordingly, shade and brightness could also be adjusted by de-composing an existing glaze.
Own tests are essential !

Stains are intermixable, but also here, own tests must be made. Please note that the maximum firing temperatures may vary.