My client is restoring an older small home type of building on his property. He completely stripped off the old finish from the old Knotty on his walls and ceiling. Now it is bare wood. I sprayed one coat of a water based sanding sealer I got at Home depot today. It made that old Knotty turn a good bit darker (it's natural color, same as if I'd of sprayed water period on it), anyways now, probably because the windows aren't large or floor to ceiling, it looks too dark for the owner and he's asked me if we can lighten the Knotty. I said I'd look into it so I am here seeking answers. So far though, I stopped in to talk with a fellow at Sherwin Williams. He showed me a bleaching agent meant evidently for small things or for spot lightening places. It doesn't promise major shifts in color and there is a lot of rinsing involved after using it. Seems that we might go through all the trouble of sanding off the sealer (in three rooms) and using the bleach product only to get what would likely be minimal lightening change at best. Does anyone here know of any better products that could really lighten up that old Knotty? He is a bit of a perfectionist and wants what he wants. I am just doing my best to find out if we can achieve what he wants somehow. Money seems to be no object to him,..thus far. I have suggested he let me finish out what we'd planned and now apply the semi-gloss water based polyurethane and be done with it. I also suggested that he install lighting in the home that is something closer to what you have outdoors (full spectrum lighting) and likely it won't be too dark anymore. Proper lighting does wonders. What do you folks think?