Sachco’s Colorfast Pre-Stain Base coat Lignin (wood cell glue) stabilizers prevent yellowing and darkening of the wood itself overtime, which in turn prevent color shifts in the stain applied over top. Light colors stay light and darker colors don’t shift too dark. It is also great as a log keeper coat because it prevents mold and yellowing due to UV damage on new wood as it moves from the mill to the job site and throughout construction. Contains both mildewcide and algaecide to help preserve the wood until it’s time to stain. Or, life happened and you need to wait for a few weeks between prep and staining? No problem.