UV Inhibitors and the Truth about Print Longevity
Tuesday, June 16th, 2009By: Adam Hill
It seems like there has been a lot of discussion recently regarding UV inhibitors in post-print protective laminates (giclee varnish). While I am pleased to see the genuine concern for archival properties and longevity of giclee prints, I feel that the primary issue is being lost in the details. The question that giclee printing professionals should be asking is, how archival are my giclee prints? This is what printmakers really want to know and it cannot be answered simply by understanding how much and what types of UV inhibitors are present in their laminate of choice. In fact, in some cases, UV inhibitors can actually detract from the quality of an giclee print. Let me explain.
Many variables must be taken into consideration to accurately evaluate the longevity of your inkjet print. Printmakers must not only understand the archival properties of their ink, substrate, and laminate, but how these variables interact with each other. Even if you are using the most archival ink, the most archival canvas, and the most archival laminate, if these products have not been tested together, the compatibility, or lack thereof, could nullify the individual properties of each variable. In other words, the final giclee print may be less than the sum of its parts. Here of a couple of examples of how this can happen.
Suppose you are applying a very archival, solvent-based laminate with a substantial amount of UV inhibitors to a very archival water-resistant, matte inkjet canvas. Though individually both are archival, the matte inkjet canvas may be too absorbent to accept the solvent laminate, which results in micro-cracks on the surface or edges of your giclee print. These micro-cracks will cause the microporous canvas to absorb impurities in the atmosphere and oxidize, causing the giclee print to breakdown and degrade over time.
Suppose you are applying an archival water-based laminate with a substantial amount of UV inhibitors onto a giclee canvas which contains Optical Brightener Additives (OBA’s), as most inkjet canvases do. The idea here is that the UV inhibitors will prevent the OBA’s from firing by reducing the exposure to UV light. (OBA’s burn up and cause the inkjet canvas to return to its natural yellow color with prolonged exposure to UV light). This is a decent idea in theory; however, it presents an entirely new problem, metamerism. OBA’s use UV light to make a substrate appear brighter and whiter than it actually is. Without the presence of UV light, they cannot be activated. Therefore, by color correcting and printing an image under UV light, then applying a laminate containing UV inhibitors, the base white point and all of the colors on top will shift as the OBA’s are not being able to serve their purpose because the catalyst has been prevented by the laminate. Most experienced giclee printing professionals know that metamerism can cost time, money, and stress.
The only way to truly know if your giclee prints are archival is to have your final giclee print tested by an organization that has the ability to perform accelerated fade-testing (Fine Art Trade Guild, RIT, Wilhelm Research Institute, etc.) At Breathing Color we provide our customers with Archival Quality Certificates which certifies the longevity of our Chromata White Canvas with our Glamour II coating, and the most prominent OEM inks in the industry. This certificate uses 2 different methods and organizations to validate its promise. If you use our Chromata White Canvas, with our Glamour II coating with Epson, HP, Canon, or Roland aqueous OEM inks, your giclee print is certified archival. If you don’t use our products, you should demand this type of certification from the manufactures of the products you are using to make your inkjet prints. Unless the canvas, laminate, and ink have been tested together and certified, longevity cannot be accurately determined. And, given that the majority of inkjet canvas and fine art papers on the market have not been print permanence tested, you should assume they are not archival.