There is a quick demo here: https://www.youtube.com/watch?v=hdBOsyogEVY
This is a substanace painter material I recently made in substance designer. Often times when making textures in substance you will want to add some subtle random color variation. I can't tell you how much time I have wasted setting up materials like this from scratch in substance painter, so making a proper material in substance designer to do this is long overdo for me. This material will make that task quick and easy for you. It works with both the metalness workflow and the spec/gloss. Please let me know if you find this tool helpful and if you have any questions. Cheers!
(lots more info at the store:)
Get it Here Free: https://www.artstation.com/marketplace/p/Aa1l5/free-substance-painter-material-color-variation-mixer