Here is a good article on using toners.  A toner is a finish that contains a colorant, a dye or a pigment.  Factories use them extensively (maybe even exclusively) to color furniture.  I regularly used them to do touch up repairs.

 

My two comments on toners

• Apply very light coats.  It's easy to go from not quite there to too much all of a sudden'
• They really work best when sprayed.  It's difficult to get an even coat when brushing.  Hence Polyshades often looks terrible.

 

 

 

 

 

 

https://www.woodmagazine.com/woodworking-how-to/finishes-finishing/wood-toning-101?hid=b0b455ea13e71c23a3fc22b044c0be06fb838bd1&did=19329554-20250904&utm_campaign=wood-online_newsletter&utm_source=wood&utm_medium=email&utm_content=090425&lctg=b0b455ea13e71c23a3fc22b044c0be06fb838bd1&lr_input=054cc015b57d54e1680d1a6048482c50e9b71e5448ad337fc319f7f4f4e52672&lr_input=054cc015b57d54e1680d1a6048482c50e9b71e5448ad337fc319f7f4f4e52672 

I tried printing it, but the photos didn't come thru.  But in case the link does not work in several years,

woodmagazine.com_woodworking-how-to_finishes-finishing_wood-toning-101_print.pdf

Forgot to say, toners are also used as "shaders" to darken or highlight certain areas.  A typical application is around the border of a raised panel (see photo in the article link).