Optical brighteners, longevity, and you.

[GrantCee]

Back in November I mentioned that I was looking for photo papers and preferred those which had lower amounts of OBAs. I'd seen the various tests and opinions from archival printing experts and was worried that the evil OBAs would ruin my photos in a few short years — perhaps even in months.

Then I discovered that most of the conventional photo papers we used back in the 1980s were just loaded with OBAs. All resin-coated (RC) and many fiber-based papers had them, and we certainly didn't worry about them at the time.

The reason I bring this up is because a month or so ago I was deep-cleaning my office and found a box of prints I'd made circa 1981. They were printed on Ilford fiber-based and Kodak RC papers, and two of the prints happened to be duplicates of ones I've had on display (well, on and off anyhow) since that time. I compared the displayed prints with the ones that had been in the dark all those years, and saw no significant visible shift in the white borders (the display prints had been dry-mounted to mat board, borders exposed, and hung without the benefit of glass. Oh, the horror...!)

Now I suppose the prints which had been kept in the dark could have deteriorated OBAs due to age, but my impression was that those compounds deteriorated under light. It doesn't look that way to me.

Although without the aid of a densitometer I can't say that there was absolutely zero change, from a visual standpoint there really isn't. That's what I'm most concerned about.

(BTW, I'll also note that none of the RC prints exhibited any of the age-related defects we were always told would destroy our prints in a few short years. No cracking, emulsion peeling, or yellowing. Will wonders never cease.)

 

[Ink stained Fingers]

I'm looking at the side as well to the OBA's when I do my fading tests, I didn't measure them regularly but can judge whether they are there or disappeared completely or partially over time. OBA's fade pretty quickly under UV/sun exposure and fade as well under no sun/more ozone exposure in recent tests during winter time. You are right - most of the RC papers come with OBA's, with one exception - HP papers carry much less or none compared to lots of other papers - HP Advanced photo paper and HP Premium Plus photo paper. I cannot confirm that the fading of OBA's specifically creates an yellowing effect. The white point doesn't change if measured with a spectrometer with a UV cut filter.

 

[Mike Earussi]

Most papers have a slight yellowish cast. The OBAs add a bit of blue to counteract that and, if used in just the right amount, can give the paper a more neutral white appearance. Look for papers with just a small amount of OBAs if you're wanting a white base that will only be slightly affected by eventual OBA fading. And once they do fade (over many years for the high quality ones) the photo will merely take on a slightly more warmer tone. And if the picture has been mounted behind glass you may not see any difference at all (since glass blocks much of the UV light).