They provide a much paler ground and do not tend to enhance grain the way some other stains do. Additional coats of gel stain do not have any appreciable darkening effect. If you want a fairly light color with very little grain emphasis, this may be the way to go. Later on in finishing consider glazing over this light ground to create a darker overall color - see Glazing below. Toning Toning means to apply a transparent colored film.
Most commercial toners are lacquer-based.
They require spray equipment. The idea here is to seal the surface with a clear coat of lacquer, sealer, or shellac. Then, apply several light coats of toner until you have the desired color. Examples of drying oils are tung oil and boiled linseed oil. As with toners, first apply a coat drying of oil if you want to pop the grain.