Has anyone tried Breathing Color Metallic?

Started Mar 22, 2013 | Questions thread
Hugowolf
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Re: Has anyone tried Breathing Color Metallic?
In reply to soloryb, Mar 24, 2013

soloryb wrote:

Interesting link (and the Aardenburg link it contains). Much of how he tests and what it means is a bit beyond me, but I did understand some of it.

Mark McCormick, from Aardenburg posts here occasionally, most recently: http://forums.dpreview.com/forums/post/51024464

My interest right now is in metallic papers (I'll eventually graduate to fine arts papers in the future) and whether or not they will fade over time due to the presence of OBAs (or Dinkla's FBAs).

‘Optical brightening agent’ is an industry euphemism, they are in most cases actually florescent – they give off light at the UV end of the spectrum when light falls on them. If you look at the plot of either the RR paper or the Moab paper, you will see more than 100% reflectance at around the 440 nm mark. The paper is actually putting out light; it is fluorescing.

From what I've read it appears that exposure to atmospheric gases is one of the main causes of the breakdown of the OBAs, especially if they are in the paper's surface coating rather than inside the paper itself protected by a resin layer.

With this in mind, would coating a paper with a UV blocking print varnish (like Breathing Color's) slow down or even prevent the OBA degradation?

Sure coatings and UV/museum/conservation glass will slow the decay of the OBAs, but they do this by preventing light in that region of the spectrum from hitting the paper. And if they do this effectively, the brightening agents will no longer brighten as much, and the effect will be the same as if the OBAs had faded. You lose a lot of the reason for using a ‘bright’ white paper in the first place.

The more expensive spectrophotometers, used for creating paper/printer profiles, can measure without and with UV light (UV cut and non-UV cut). Specifically for this type of situation – UV emittance under UV blocking material.

Brian A

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