Brod-Dugan in St. Louis, a regional manufacturer, doesn' t list ingredients even on the labels of its paint cans, other than citing a material here or there in terms of a health hazard. The product literature available at one Brod-Dugan store for a premium brand of interior flat latex contained no information about formulation, either. But the product data sheet from the factory got no more detailed than identifying the latex binder and showing the volume and weight percentage of solids. Not really, say paintmakers. It's not so much what the ingredients are or how much you have, but how you use them.
Contractors can be on safe ground with some simple comparisons.
Take binder levels, for example. A contractor buying an exterior primer needs all the binder he can get for adhesion and sealing. If primer A has twice as much binder as primer B, and they're close in price, then the decision is easy. However, ingredients vary from brand to brand. Two rival brands of interior latex flats may include equal amounts of acrylic binders, but unbeknownst to the contractor, they may be entirely different acrylics, unequal in quality.