Optical Brightener Additives – what they are, what they are used for, and more.
There’s been an intellectual debate about the use of Optical Brightener Additives in inkjet canvas over the years.
While the overwhelming majority of archival testing institutions, professional printmakers, photographers, and fine art product manufacturers advocate against the use of Optical Brightener Additives when print permanence is desired, I still see an occasional outlier advocating their use in articles, blog posts, and other means. Though probably unintentional, I believe such actions are irresponsible. In this article I will illustrate why.
Before I begin, it should be noted that even as I write this article – an article that will clearly warn against the use of OBA’s when long term image permanence is desired – Breathing Color still offers both options; canvas with OBA, and OBA-free. We believe each product serves a specific purpose, each for a specific market. Presented with all the data, we prefer to let our customers decide which option is best for them.
What are OBA’s?
Optical Brightener Additives (commonly referred to as “OBA’s”) are widely used in paper and canvas coatings, textiles, and laundry detergents to increase the perceived “whiteness” of the treated products. OBA’s work by absorbing light from the (invisible) ultra-violet end of the spectrum and emitting light in the (visible) blue/white range of the spectrum. This “shift” in the frequency of light energy, results in a whiter and brighter appearance of the treated product.
(For a more in depth article on the topic, click here.)
Why are they used?
Many digital inkjet printmakers prefer a bright white surface to print on, to the true surface color of their naturally-yellow substrate. As a result, canvas and paper manufacturers are adding OBAs to the digital inkjet receptive coating (IRC) used on their papers and canvas’. The reflection of white light emanating from the OBA’s will completely overwhelm the paper’s natural color, creating a higher perceived whiteness. Popular rag papers that contain OBA’s are the Hahnemuhle Photo Rag, Somerset Velvet, and Breathing Color Elegance Velvet.
The Problem with OBA’s
While OBA’s appear to be an effective solution for enhancing the whiteness of inkjet media, OBAs can pose a serious threat to the integrity and longevity of a fine art print by causing metamerism, which leads to color shifts and by accelerating yellowing over time.
A Do-It-Yourself Archival Test shows how harmful OBA’s are
I did this test at home in one week. It’s incredible to see how OBA’s can degrade this quickly.
OK, I know what you’re thinking. “What happens if I try this test with a different archival print varnish?” We’ve tested them all. Clearstar, Premier, Hahnemuehle, etc. The results are the same – no archival print varnish can stop the degradation of OBA’s in canvases where they are present..
Archival Testing professionals advise against the use of OBA’s
The Wilhelm Research Institute, one of the traditional authorities on print permanence, was among the first to stipulate that “When long-term image permanence is an important consideration – or may eventually become an important consideration – fluorescent brighteners should be avoided.” Wilhelm Article When you look at the results of my Do-It-Yourself Archival Test, this conclusion isn’t very surprising.
OK for Décor, not OK for Fine Art
If long term image permanence is not an issue for you, of course OBA’s are ok. If your prints aren’t going to be directly or indirectly receiving exposure to sunlight, OBA’s are probably ok. Even with low to moderate exposure to indirect sunlight, your prints may not noticeably shift in color over the lifespan of their intended use, say 5-10 years. Frankly neither I, nor anyone else can definitively state how long a canvas print will last if it contains OBA’s.
Therefore my position is that OBA’s can be safe when the application is décor (lower priced prints, not intended to last, no implied warranty) whereas OBA-free is most appropriate for fine art (high priced prints, intended to last, when there is an implied warranty).
It’s called being responsible
Why did we spend the money and resources to develop the first OBA-free canvas in 2005? Why do we advise our customers to avoid OBA’s when long term image permanence is desired? Why am I taking the time to write this? Because it’s the responsible thing to do. I don’t want any of our customers to be at risk of a lawsuit or some other huge problem because they were misinformed or not informed at all. I believe we have a responsibility to inform our customers of all the pros and cons, and let them decide on their own.
We’re not the only ones
Although we were the first to release an OBA-free canvas in 2005, we’re not the only ones who offer an OBA-free canvas. Today, there are other options out there. Therefore I’m not advocating that you use any specific product, such as ours, or that we’re the only option.
We weren’t the first to release an OBA-free fine art paper either, Epson was. With the advice of archival testing institutions and professional photographers, Epson delivered the “Ultrasmooth Fine Art Paper” in 2003. We applaud Epson for this valuable contribution to the industry.
I encourage you to try my Do-It-Yourself Archival Test on your own. The truth is, you don’t need an institution to tell you what will last and what will not. You certainly don’t need me for this either! In a matter of one week you can see it for yourself. Try out some different canvas options, with and without OBA’s. Try different varnishes. Try some fine art papers and décor art papers. Test them behind UV protective glass, and without protection. Have some fun with it. In each test, include a product claimed to last 100-200 years by an accredited institution to use as your benchmark. See just how the other untested or invalidated products stack up against it. You won’t believe what you find.
Empowered with accurate and truthful information, you can make the choices that are best suited for your business. I hope this article has encouraged you to take control of your own quality and discover your own truths about the products you are offering your customers.