Yes. Optical brightening effects can appear in colored papers too, though not necessarily for the same reason as in white papers. Some colored papers use substrates that fluoresce under UV, so they can still show a UV response even when the paper itself is gray or pastel.

There are also specialty colored papers made with fluorescent dyes. In these cases, the dyes are used not to make the paper look whiter, but to make the color appear more vivid. These dyes can absorb shorter wavelengths such as blue and green light and re-emit it as warmer colors like yellow, orange, or red. That’s why very bright poster or flyer papers can look especially intense.

So while OBAs are most associated with whitening white paper, fluorescent additives are also used in colored papers to increase brightness or saturation.