Whether you’re a photographer making prints or a collector of photography, you need to know about Optical Brightening Agents (OBAs)
Full episode transcript
In this episode: Whether you’re a photographer making prints or a collector of photography, you need to know about OBAs.
In this episode of the fine art photography podcast, we will learn about OBAs. Optical Brightening Agents — are they really as bad as they seem?
Optical Brightening Agents, also called fluorescing whitening agents, are chemical compounds — actually one site called them a form of dyes — that are added to papers, fabrics, laundry detergent, and other materials where a bright white appearance is desirable. I’m no chemist, but my understanding is that the OBAs fluoresce under UV lightwaves, reflecting more of the attractive blue-white light waves back to the eye.
In addition to making paper look whiter, OBAs also help manufacturers produce consistent batches from run to run.
Papers with little or no OBAs often look somewhat yellow or ivory in color, and they are often called “natural white.” But bright white photographic paper is great — why wouldn’t we want to use OBAs?
Red River Paper Company, on their page about paper grades, say that what they call “archival grade papers” may have some OBAs which — and this is a quote — “does not indicate your image will fade faster. It does predict a slow change in the white point of your paper, especially if it is displayed without UV filter glass or acrylic.” In other words, the presence of OBAs may make the appearance of your photograph unstable — the paper may yellow over time, especially if the paper is not behind a UV protective glass. They describe “museum grade papers” as the most archival option — the one that museum curators would choose — and that museum grade papers contain no OBAs.
One of the problems with OBAs, as discussed by imaging experts at Aardenburg Imaging, is that we know OBAs will lose their effect over time, allowing papers to yellow, but we don’t fully understand how they’ll fade in a predictable way.
Also, OBAs are designed to fluoresce with UV light, and in the presence of other types of light, the print may look different. And if the print is glazed under conservation glass, UV light will be blocked, which counteracts the effects of the OBAs anyways, defeating their purpose to begin with.
As a photographer, I can tell you that while there may be a lot of nice photo papers on the market, there aren’t a huge number with zero OBAs. The best way to find out about OBA content is to consult the tech specification sheets on the manufacturer’s websites. Most of the best paper companies produce some lines that contain no OBAs.
You can also check the fluorescence of paper using a UV LED light — essentially a black light — to see if the paper glows blue. Most of the high-end print labs who discuss the topic of OBAs online just recommend that we avoid papers with OBAs altogether.
And while we are talking about inkjet papers, this is not a new problem. OBAs have been present in darkroom papers in the past as well. One site showed an Ansel Adams print fluorescing under the blacklight.
Anyways — food for thought everybody. As for myself, I am actively using on-OBA papers as often as I can.
Thats all I’ve got for this episode — thanks for listening and I’ll talk to you again real soon.
Chromaxion, “Paper for Fine Art”
Red River Paper, “Product Grades Explained”