Correcting Finish Fading Caused by Light

Advice on how to even up the finish tone in an area where a hanging mirror has left its shadow on a cabinet end. May 16, 2014

(WOODWEB Member):
I have a client with 4 year old Bulthaup cabinets/planked walnut. Recently she removed a wall mirror that was hanging on an end panel and an outline of the mirror remained, darker behind, lighter around the perimeter - a classic case of light fading. The finish (unknown) is very light and appears to be boiled linseed oil, no stain. Does anyone know of a remedy that would either lighten the darker (original) area or darken the faded area?

(Finishing Forum)
From contributor M:
Well if they are in fact Bulthaup cabinets, there is no way the finish is boiled linseed oil. They were using a 2K poly till about 5 years ago, then switched back to a conversion varnish. Itís not all that difficult of a fix though. If itís possible I would remove the end panel and remove the finish either with chemicals or abrasives. Tone it and refinish it. That's about the easiest way.

From the original questioner:
Hmm. I guess I need to look closer, just didn't appear to have much of a finish. Thanks for the help.

From contributor C:
It seems the logical conclusion would be that the darker area caused by the mirror would patina just as the rest in due time. If you tone and finish, the rest may not match after the sun takes its toll.

From contributor M:
That's true, you have to even out the color by sanding or scaling, but it has to be removed. I thought that would be obvious. Then you can refinish the panel.

From contributor D:
You need to determine if the cabinet finish has faded or the finish under the mirror has ambered. If this is a linseed oil finish, as stated, the area under the mirror has most likely ambered due to light deprivation. Oils/alkyd finishes are photo reactive and will amber when light is blocked. Trying to match either the patch to the cabinet, or cabinet to the patch - each has the possibility of showing up in the future. Once the original finish on the patch reacts with the UV light... I would first try to treat the darker patch with a UV light source to see if it will lighten without lifting or refinishing.

From contributor E:
Throw a UV light on that area for a while. You can tape off the perimeter so that you are only exposing the previously hidden areas.