I have a historic house and the trim has all been painted with oil base enamel. I know I have to use oil on top of it, but it turns yellow after a few years. Why and is there a product that does not turn yellow?
All light or white oil base paints start to turn yellow after a few years. The only way to avoid this is to use a 100% acrylic paint instead. Acrylic paint is way more color stable. Simply prime the existing oil base paint, fix anything needing repair then paint with a good acrylic.