Baryta budget alternative

Started 4 months ago | Discussions thread
dRomano Regular Member • Posts: 261
Re: Baryta budget alternative
1

Mark McCormick wrote:

Easiest way to determine OBAs and even to some degree the magnitude of the optical effect which may get compromised when UV blocking glazings are used is to shine a UV LED flashlight on the print surface. Lots of OBAs....Lots of "bright blue glow" from the flashlight. Place a UV blocking glazing over the paper...little or no "blue glow".

Note: LEDs intended for indoor lighting have almost no UV content. UV LEDs are specially formulated to emit UV radiation, the peak is typically 365 or 395nm. The 365nm variety is better for detecting the paper fluorescence, but both wavelength UV LEDs will get the paper to fluoresce noticeably when OBAs are present.

Exactly right, I bought a 365nm flashlight and it was very illuminating. I had lots of sample papers from the various manufacturers and could really see the difference in brighteners in them. Some papers that claimed to be OBA free are not, and while I'm not trying to go OBA free, I do prefer low amounts. Plus, my spectro cannot compensate for them, so I'm better off with little or none.

A couple of other interesting things I learned were that my old darkroom prints I made 20 or 30 years ago are in fact not OBA free and still shine about the same as my preferred ink jet papers, despite being displayed for 20 years. That put things in perspective for me.

Also, I like to mount prints without glass, so they need to be sprayed. The sprays have good UV inhibitors, so, easy right? Think again. Put a couple of coats of spray on the print then shine your UV flashlight on it. Lots of speckles. You can really see how unevenly the spray goes on. I don't know how many coats give full protection, but I stop after 4 or 6 because it not only can get expensive, but the sheen of the print gets too affected by the spray. Plus dust collects, and God forbid a drip happens because you got an itch on your foot while spraying the last coat, etc!

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