Previously the panel had light white woodstain on it (well actually, diluted emulsion paint), covered with acrylic varnish. Now it has white satin paint for wood on it.
I found a tin of "clear satin outdoor varnish" in the shed & thought "this must be tough stuff". I started slapping some on the panel today --- it was yellowish or light brownish, not clear. So I stopped to see if it cleared on drying. Nope.
Is it likely to be discoloured (well, coloured at all) because it's old? (It looked to be in good condition when I opened it.) Or do I need a particular kind of "really clear" varnish to put on top of white paint?