White Gloss Yellowing

[Prudie]

Why does white gloss, on windowsills mainly, go yellow if it's covered with ornaments, curtains, out of the light basically? I'd expect that area to be the one that stays pristine and white.

[tonyav]

Sunlight, I should imagine.

[Prudie]

Tony that would seem the obvious answer but it's quite the opposite - the uncovered in full light stays white, the bits that are usually covered with a vase for example go yellow.

[tonyav]

Perhaps it's the lack of light then, maybe affects the pigmentation in the paint somehow.

[BRIGHT SPARK]

Is it white gloss or brilliant white?

[theshedman]

Yes that's the reason, lack of light. This will happen with most colours but you see it more with white. As it is being deprived of natural light it will go yellow the same as it does in a cupboard or if you have a door that is always left open against a wall then when you do close it you will see it is a different colour to the rest of the gloss work that has light in the room. Not really much you can do about it though.

[heathfield]

All oil-(solvent-) based white paints will eventually turn yellow, more quickly in darkness, as Shedman says, where the bleaching effect of light is absent. But one answer is to use white paints that are water-based. These will stay white, though the gloss ones won't provide the same level of gloss as oil paints