If your into printing then there is a hot and vocal debate on the use of OBA’s.
First what is an OBA?
Well its an Optical Brightening Agent. In the old days this was a coating on the paper, now most papers that have OBA’s have it built into them.
What does it do?
It turns Ultraviolet light outside of the visible spectrum and fluoresces it into white light that can be seen, this then gives a pure bright white that makes the blacks look black and improves the contrast of the image.
So why the debate?
Well back when they first came out the coating wore away, not an issue as then the paper acts like a natural paper, the issue was it wore unevenly and made your prints look blotchy.
Manufactures say they have now fixed this and that they will wear evenly, but many photographers and printers who want the work to last do not trust them anymore.
If your picking a paper that uses OBA’s you also need to consider how it will be displayed; if framed behind glass or most modern perspex then it will not work and you will get a normal white. If its framed in a room receiving little natural light then again you will not get the affect.
I have been testing some papers recently that have OBA’s and the whites can be better then naturals but there are also other methods to get a better white that can be used.