Brand new wax cells, before they are filled, are always a nice clean white. Some bee types also have a reputation for producting very white cappings - Italians for example. One of my Buckfast colonies produces noticeably whiter capped honey than the others, which are creamier in colour. Snow-white capping is nice for cut comb.
If it's the cappings that strike you as particularly bright white in colour, perhaps your local mutt/wild bees have a lot of Italian ancestry...