D50 and D65 each represent different lighting environments that reveal the effects of fluorescence differently. D50 is the mandatory standard for quality control during printing and matching technical proofs. Conversely, D65 is used to simulate ambient light in retail stores and final consumer evaluation.

Since the UV content differs between D50 and D65, an OBA paper may be acceptable in the pressroom (D50) but appear bluer in a retail environment (D65) due to greater fluorescence emission. Therefore, simultaneous attention to both ensures that technical quality is maintained in production and visual consumer satisfaction is met.