Wednesday, January 28, 2015

Fluorescent Whitening Agent µ-conference

I have some good news. I counted 64 authors that will be representedat the 2015 TAGA Annual Technical Conference. We are still making adjustments to the program, but once things settle out I expect there will be 35 papers presented at our conference in Albuquerque. As vice president of papers for the Technical Association of the Graphic Arts, it has been my awesome privilege not only to decide which papers to accept for the conference, but I also got to read the abstracts.

TAGA Annual Conference, March 22 to 25 in Albuquerque

As I reviewed the abstracts over a couple of bottles of Shiraz, I noticed something odd. I mean something other than the fact that I was drooling. There were six abstracts submitted on different aspects of the same topic: Fluorescent Whitening Agents (FWAs). Imagine that! So as VP in charge of papers, I made an executive decision. I declared that TAGA 2015 will have a Secret Agent Micro-Conference on Fluorescent Whitening Agent Metamerism. That's pronounced "SAM-ka-FWAM", in case your wondering. And yes, I am in secret negotiations with a certain well known comic book company about licensing the super hero.

Note: FWAs are also known as Optical Brightening Agents (OBAs), and Secret Agents, but FWA is the more better term cuz it’s more scientifical and all that. 

Just in case you are wondering about FWAs and the new M1 condition, I have done a bit of writing on the subject.

A megacool UV flashlight on three paper stocks (left) and a white LED flashlight (right)

Here is a fabulous preview of the six fabulous papers on FWAs…

In 2014, Bruce Leigh Myers presented at TAGA, telling us that the handful of spectros that he could get his hands on (at RIT) didn't agree with each other as well as one would hope. No flat out shouting matches, but he was disappointed that they formed little cliques.

Later in 2014, he took his FWA test samples on the road to GraphExpo and wandered around, forlornly asking anyone who would listen to measure his samples. His new results will be presented. Will there be close agreement? I have my guess, but I’m not going to share.

Veronika Lovell (from Sun Chemical, with the help of Robert Marcus and Danny C. Rich) took up a similar challenge and looked very closely at three instruments that came from three different manufacturers. She, too, found significant disagreement. She had a hunch about what might be causing the difference and got out her slide rule to test this hypothesis. I can hardly wait to hear her results!!

David Wyble (of Avian Rochester, LLC) heard some people talking about all this “instruments don’t agree very well” stuff. He decided to dig a little deeper, asking some probing and fundamental questions. “Are the requirements specified in ISO 3664 and ISO 13655 adequate for the evaluation of instrument sources? Can the acrylic standards adequately simulate the behavior of the fluorescent compounds in commercial papers? How might physical standards be applied to the instrument profiling process? Can two instruments be adequately aligned either spectrally or colorimetrically?”

The even deeper question that will be answered is whether his co-author (John Seymour) will hold up his end of the deal and actually help out! Of course, we all know that John will take credit for the whole idea regardless.

Of course, measuring color is not the only issue when it comes to FWAs. We must also be able to assess color by eyeball in a standardized way. To do that, you need a standardized lighting with a standardized UV content in a standardized viewing booth. And you also need a way to make sure that your viewing booth really does have the spectral output that is claimed on the wrapper.

Every year, the Printing Industries of America gives out InterTech Technology Awards to recognize new products that are expected to make a difference in the printing industry. Just Normlicht was one of the 2014 recipients, and as such, they get a shot at giving a technical presentation of their technology at TAGA. Eric Dalton, who just happens to work for Just Normlicht, will give us a rousing overview of this instrument that is just another piece of the puzzle when it comes to taming this FWA monster.

How big is this monster, anyway? It’s about time somebody did a study on that! Luckily, somebody did. Changlong Yu did his Master’s Thesis on that topic. Not monsters in general, but one particular monster. Lemme ‘splain.

You print a proof, likely on an inkjet printer onto inkjet proofer paper. You take that proof out to press and try to match it. But you’ve already got one arm tied behind you back. The paper will be different. It’s likely that the FWA content is different. Changlong did a lot of psychometric testing and will report on how much difference is perceptible. You gotta love research that includes psychometric testing.

I dunno… some folks actually want to get paid for print jobs. That’s a concept a little beyond me, but Bob Chung is interested in the practical aspect – the application of Changlong’s research. Bob took the perceptibility difference a step further, and looked at how much of a change in color (due to FWAs) is acceptable. The cool thing is that he comes to a recommendation that is quite simple.

So, between the two previous papers, we got the hard copy proof thing nailed. How about softproofing? Peng Cheng wanted to address this part of the puzzle for his thesis. Peng used substrate corrected colorimetric aims to build profiles, and then did psychometric testing. There it is again… psychometric testing! Yes!

Did anyone notice that I said there were six papers, and then I talked about seven? You can't trust a math guy to count correctly.

All in all, I think we got us here the makings for the best Secret Agent Micro-Conference on Fluorescent Whitening Agent Metamerism since God said "Let there be light". Meet me in the bar afterward and I will teach you the SAM-K-FWAM secret handshake.

Oh I almost forgot. We have 29 other great papers that will be presented!

1 comment:

  1. Fluorescent brightener is used to whiten the fibre and paper chemicals. Optical brighteners are added to fibre lining that so that the fabric color is more bright, slowing fabric yellowing.