It may help to substitute the words Professional for Trade and DIY for Retail. Trade paint is manufactured using higher quality ingredients, in particular superior pigments, hence a slightly higher price.
Trade paint provides higher coverage. A typical Crown retail matt emulsion will cover up to 14m2/L, whereas the Crown Trade matt emulsion we mix here will cover up to 17m2/L. In addition retail paint is generally made to be used "straight from the can"; Trade paint, whilst it is still ready to use, can be thinned down.
Opacity in paint terms refers to the ability of a coat of paint to hide the substrate, wall or previous coat of paint from view. Retail paint has a lower opacity meaning you may need 3 or 4 coats to satisfactorily cover the previous coating. Trade paint has a higher opacity meaning fewer coats are needed.
Because of the higher quality ingredients, Trade paints give better durability and hence a longer life expectancy.
Trade paints offer more substrate specific products so you can use the most appropriate materials for the job getting even better results. IN SUMMARY, when comparing paint prices bear in mind these points that actually mean in effect Trade paint is not only better quality, but ultimately better value for money!