UV brighteners in paper can "fool" the spectrophotometer and result in profiles that look too yellowish. There are a few ways to compensate for UV brighteners and get a normal-looking profile. One is to attach a UV filter to the spectrophotometer. The i1 spectrophotometers are available with a UV filter, but they must be ordered with this feature and cannot be changed by the user. ColorMunki comes only with a UV filter and iSis has user switchable UV options as well as an OBC viewing tool option. The other way of compensating for UV brighteners is to use a profiling program with built-in compensation. ProfileMaker 4 and later, and i1Match 2 and above include software compensation for UV brighteners. With these programs it is not necessary to use a UV filter.