I am planning a portfolio which will use either Entrada Rag Bright or Entrdaa Rag Natural. While leaning towards the Bright (and the ability to use Kayenta Matte as the proofing paper), I have some lingering concerns about the effect of the OBA used in the Bright. Does the OBA this paper uses have any material effect on prints either (i) on display under glass or (ii) generally stored in a portfolio box?

Great question, Anthony. As you know, we offer Entrada in two flavors: the Natural with no OBA's (or Optical Brightening Agents), and Bright, with OBA's. Both these papers are acid-free and neutral pH, making them archival. We introduced OBA's into the Entrada Rag Bright to provide a paper for those requiring a brighter surface for their images. Over time, OBA's will fade returning the paper to its natural state, which is equivalent to the warmer tone of the Entrada Rag Natural. So, over time, the appearance of your image will change as the surface becomes warmer. It's important to note that as these brighteners lose their effectiveness, the durability of the paper is never affected.

The degree of visual shift in an OBA paper that occurs over time can vary greatly due to the base materials, quality of paper, and UV exposure conditions. The Entrada Bright and Entrada Natural are the same base paper, except for the addition of OBA in the Bright. Because of this, we can confidently say that a reduction in OBA florescence over time won’t make a ‘dull’ print on Entrada Bright.

Another critical part of the question is how you will frame or display the prints. If you are framing behind a UV blocking glass, the Bright will look nearly the same as the natural because minimal UV light is reaching the paper to activate the OBAs. In this case there should be little or no appearance change over time.