UV brighteners in paper can "fool" the spectrophotometer and result in profiles that look too yellowish. Why does this occur, and what can be done to eliminate the artificial yellow emphasis in the profile?
The human eye sees papers with optical brightener as a brighter white, whereas a spectrophotometer will "see" the optical brighteners as giving a blue cast in the paper, and therefore will cause some profiling software to add yellow to the resulting profile.
There are two ways to compensate for UV brighteners and get a normal-looking profile. One is to attach a UV filter to the spectrophotometer. The i1, DTP41, DTP45, and Pulse spectrophotometers are available with a UV filter, but they must be ordered with this feature and cannot be changed by the user. The Spectrolino spectrophotometer has an accessory UV filter that can be changed by the user. The DTP70 and iSis both have user switchable UV options.
The second way of compensating for UV brighteners is to use a profiling program with built-in compensation. Both 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.