in 2010 the whole paint industry were forced to make changes to the way they make paint and that the ensuing reformulations have meant that this yellowing process has been much swifter for some customers than they experienced prior to 2010. So what are these changes that Dulux are referring to? Well, it was the EU that forced companies like Dulux to change their oil paints. For environmental reasons, it ordered paint manufacturers to reduce the amount of Volatile Organic Compounds or VOCs in the paint. Martin Horler, a Consultant in Decoration says, "To get rid of the VOCs or lower the VOCs you have to reduce the solvent, if you reduce the solvent you have to increase something else and so what they will have to do to keep it in liquid form will be to increase the drying oil which unfortunately causes more rapid yellowing of the paint."
I would reccomend dulux quick drying satinwood. Mine hasn't turned yellow in years and its not oil based so you can clean brushes without turps. The finish is far better than gloss with no drips etc. The downside is its supposedly not as hard wearing but I've never had a problem with it.
Yes it was to do with that also but no natural sunlight also causes it. The only alternative is to use a water based gloss.
That's the reason Dulux is no good it relies on light to stay white. I hang my dressing gown behind the bedroom door and when i remove it there is a big yellow shadow.