US #11A - In Search Of The Elusive Plum Color

If I am reading the Philatelic Foundation's website correctly, a PF certificate identifying a color or shade effectively means, "It is this shade or color and always has been." This is because if the stamp is a color changeling or color affected, they are obligated to so state on the cert.

As for the light source, all we can say is that PF is expertizing colors and shades based on whatever light source they have determined is correct and have used consistently over time, at least recent time. I would guess it's an Ott-lite daylight color lamp.

However, the foregoing is not scientific enough for me. Therefore, I propose that expertization of color or shade varieties shall require the illumination of the subject via an electric light source having color temperature of 5000 Kelvin and output of 900 lumens emitted from directly above the subject at a distance of 50 cm. Comments from the community are invited.

Unfortunately, this begs the question: viewed with whose eyes? Ultimately I feel the only solution is using a scan with a high-quality color scanner, color calibrated using an industry-standard color chart, then subjected to spectral analysis. There is work going on in this area by those submitting to the Institute of Analytical Philately.

I agree with cjpalermo - we need a very specific, standardized process to determine color. I expect the end-all test would be something like a spectral analysis. That should take the human eye out of the equation. At some point, we need to consider cost. I don't know the cost of a spectral analysis test, or the equipment required, but it can't be $0. Also, I would expect the chemical make-up of a true plum ink to be slightly different (and measurable) than, say, a claret shade of ink. Perhaps chemical analysis is the answer. And, another huge point to consider: what happens to these properties over time. God knows, all of these colors change over time and are subject to accidental and purposeful environmental issues. The dynamic aspect of these inks would then come into play. Or we can just pay a recognized (and THAT'S where the problem lies...) expert to look at it and say, "It's plum", or "It's dark grayish claret", or whatever. The phrase, "It doesn't make sense to build a $1000 fence for a $100 horse" springs to mind.

If the only widely accepted test method is a $1000 test, we have a problem. Sure, the 'purists' with deep pockets could take advantage of such a test, but 99% of the plums out there will suddenly lose value because they will never be subject to those tests. So, after all that, IS THERE even a recognized color expert ALIVE today. I think Dr. Amonette (and Chase, too, I suppose) are as close as we've gotten to a universally accepted expert in the field, but they are gone. Who do we have now? There are some very good people out there, but could they be considered to be 'universally accepted'? Any nominees for the title??

Classic Coin, to answer your question, See, "Colors of the Three Cent 1857-61 Perforated Type II Stamps (S4 and S5), by David T. Beals III, Chronicle of USPCS, February; 1974, Vol 25, No. 1, 14.

(italics mine) " . . . Dr. Chase('s) . . . did considerable additional work on the colors of the 3c stamps after the publication of his book, and that he prepared at least two charts of the S4 and S5 colors as he knew them. To several of the rarer shades (not mentioned in his book) he assigned names from Ridgeways' book (Color Standards and Nomenclature by Robert Ridgeway, self-published, 1912). . . . .

The first change made by Dr. Chase was to narrow the designation of Plum (as he had used it in his book) to one specific Ridgeway color; and the designation of a new color, Purple Claret. This change is still not generally understood, and continued use of Plum instead of Deep or Purple Claret by most dealers and auctioneers has been in error and has greatly confused the proper identification of both colors by most collectors. "

cjpalermo1964 writes, "I feel the only solution is using a scan with a high-quality color scanner, color calibrated using an industry-standard color chart, then subjected to spectral analysis. There is work going on in this area by those submitting to the Institute of Analytical Philately."

It has been pointed out in articles cited in prior posts of this thread that the colors of the 3-cent stamp were studied in two ways, the first as strictly by color analysis, and the second by chronological order. The second method is what is used generally (and by myself).

Elsewhere in this form it is pointed out that the mineral inks of the 1850s do not conform to color standards as we know them today. It would be necessary to reconstruct the colors from the original formula(s) in order to assign a proper designation(s). Someone (a historian perhaps) would have to go back and research all the potential colors available to a print shop in Philadelphia during the 1850s, and then using these colors reverse-engineer the shades we find on the 3-cent stamp. Ref: https://goscf.com/t/63578&SearchTerms=color)

I also have this from first-hand accounts of Dr. Ammonette that he felt quite strongly against the scanning of stamps since he believed the high intensity light would cause further (UV) damage to the color(s). This is the reason why I currently avoid scanning of philatelic material produced before the complete introduction of aniline inks (that are more UV resistant).

There is what is called an XRF analyzer which uses x-ray fluorescence to detect the percentage of each chemical element (copper, oxygen, etc.) in a tested item. It is generally in the form of a handheld gun and provides a readout of chemical composition by element. So you will get variant readings based on any oxidation products present. Accuracy is probably dependent on cost, as I've found them to range from $1500 to several tens of thousands of dollars but the "cheaper" ones I've seen give readings down to a 1/10 of a per cent of relative composition. If the PF and APS don't have these, I would be surprised.

The method is non-destructive; look up the method to see how it works. It has been used for years in the art world to establish pigment content, often to determine if paintings are forgeries or not. For example, lead was used for white color historically up to the early 20th century. Titanium dioxide was used from then on, so a modern/post WW2 forgery of a classic painting is detectable that way.

To me, the chronology/plate would also have to agree. Remember that tgswanner passed on the observation by Dr. Ammonette that certifiers (also) identified other shades that they called "plum". We don't happen to know what their criteria is. So Classic Coins sending in the second stamp was worth a shot. Now, is this still true? It might not be for the PF per Billw2's post. But again, we don't know for sure.

Comparing color by eyeball and personal exam standard is not the way I would expect an expert opinion to be done except in the case where it's an "either this or that" color choice.

Note that XRF analysis would likely uncover chemical bleaching or color alteration as well, assuming a known example was available.

To me, this whole conversation begs the question: How do the certifying organizations determine a 'plum'? Is it all about having an 'expert' look at it and say, "Plum!"? Or, more to the point, THEIR expert? Does 'their' expert have real-life examples of 'plum' at his disposal, along with other, close, shades? Are any spectroscopic and/or chemical analyses done? Are these tests available at extra cost? I just don't know what the PF (for example) does. And lack of transparency is probably by design. Even if the procedure has been stated in the past, how do any of us know if that is the truth? For the sake of argument, I would be interested in knowing how close can a faker get to 'plum'?? Is it possible to get pretty darned close using a specific chemical and/or electromagnetic (light) method being used on a specific (NOT scarce) shade? Or, is it just not possible to get very close? Can one get close enough to fool an expert's eye? IF that is possible, then a chemical/spectroscopic test would almost be necessary. Because there simply aren't too many plums out there, I suspect it is not currently possible to alter a common stamp to get close to 'plum'. But, what do I know?? Back to the lab...

Thanks for all the interesting comments, guys.

Here is proof that the PF used the Amonette notes I sent in with my submissions. They wrote the certificate number on the notes, and returned them with the stamps and certs. They did the same for the Copperish and Yellowish Orange Brown on part India paper stamps I sent in.