Two 10A Stamps In "Bright" Orange Brown Do Not Match

If peroxide is used, yes it would remove oxidization to a certain extent..You have to remember 160 years ago was probably not the best ink mixing process as it is today.

Back then it was what I called puddy knife mixing...The whole print of one stamp was not done in one day..Even when I was a printer, it was impossible to mix the exact same colour the next day...You will (even after a peroxide treatment) never get the exact same colours from one day to the next, from one stamp to the next...Shades will always haunt stamp collectors.

Dr, Jim Watt, a large Canadian stamp collector sat at my dining room table one night and asked if I would help him build a process of stamp colours/shades and I said Jim..impossible unless we get access to stamps originally printed and stored out of sunlight, out of pollution...He gave up on the idea...

We even thought about taking a stamp to a paint store..Run it through their paint analysis program and get a #....That way if you waned to see what I had, you could go to the same store and get a card/sample of that # and you would see what I was looking at.

Robert

It exists and I was told it is currently being used by expert groups; since when I don't know. The method is x-ray fluorescence or XRF, with a hand-held gun giving a readout of elemental composition by percentage (so not compounds). It's non-destructive; look it up. It's been used for expertizing paintings for some time to check (for example) the composition of paint by time period of use, or compare materials used in a painting of unknown provenance against materials in a known painting by a specific artist.

XRF analyzers cost many thousands of dollars so personal use isn't really in the cards today.

Reliable color matching can be done with consumer-grade scanners. That's not the problem. The problem is with the references. There are no actual technical color references from 160 years ago. Or even 5 years ago. And the references change colors over time. We can scan stamps now and know with precision what color they are. We can scan them again in a year or a hundred years from now and know if they changed. But we cannot really know how stamps today match the colors when they were printed. The best we have is literature and in the case of the 3c Washington, we have a really good start with what Chase, Amonette, Beals, and Hulme put together.

I'm trying to put together the best reference collection I can on the 3c. I might be able to male it useful for other collectors if I did some work on making sure I have good equipment and calibrate it. And rescan all my stamps under absolutely the same condition. My scans now are almost all the same condition, but the backing color (black vs white) makes a difference as does the presence and type of clear covering.

I'd add that if stamp collectors need to analyze the chemical composition of stamp ink to determine two shades that are identical to both eyes and a color scanner, then those two stamps are not different shades at all.

I assume that the color differences are noted because the ink change was recorded in Post Office records?

The H2O2 Treatment made a HUGE difference!

Before:


After:


Other "Bright OB"



I used peroxide on a number of other dull-looking stamps, and all of them changed drastically - and not just lightening - some got darker. . .I may make a separate post about this. . .the differences are striking.

Yep, not at all surprising.
That's the stamp (or close to it) that Bill colorized.

I wonder how it was stored for the last decade.

Do you have an evidence or references that you can supply on this opinion?
Don

Don, if you scan something it can mathematically tell you what color it is. If you calibrate your scanner to something known such as munsel color samples, you can be pretty sure that you can repeat results, even on different machines at different times. You can scan something now and be sure that the file won't change over time (using the right file format) and be able to use the digital file as an unchanging reference. A scanner definitely cannot tell you what chemicals are in your ink, though.

I agree that Munsell targets and color system are a good approach to calibration but how many folks in the hobby are going to spring for the cost? Targets are north of $100 (US) and Munsell recommends they be replaced every few years. And then you have to also spring for calibrating your display monitor since calibrating a scanner without calibrating your display is useless. And you need to re-calibrate often, typically every few weeks or if the ambient lighting changes at all.

Then you to always save any scanned image as a uncompressed TIFF file since saving the scanned image with any compressed file format like JPG will change the scanned colors. Uncompressed TIFF files are very, very large so you will not be uploading any of them to most online sites.

For these reason, few stamp collectors bother with calibration.

Consumer grade scanners are fine for scanning family photos and the color are certainly accurate enough to tell red from blue without calibration.

But the issue at hand; dealing with what are often very subtle color differences between stamps requires a much more exacting approach. Adding in a technology layer makes a hard topic (color ID) even more difficult and costly.
Don

Don, you bring up a few points to consider, but some issues are very minor.

- There is no "ambient light" issue within a scanner. If you scan a handful of known color references (e. g. Munsell color chips) at different times and places, or with different machines and get the same result, that's all you need to do to make sure scans of unknown items will be consistent.

- a few hundred bucks for color samples every few years is no obstacle to someone spending tens of thousands or more on stamps in the same period of time. Note that you would not need every color to match to your stamps. . .you need a handful of them to calibrate your scanner.

- You would not need to calibrate your monitor. You can be color blind and using a black and white monitor to match colors. The computer would be what is judging colors.

- there are multiple file formats that do not alter colors, but storage is cheap and you can store millions of pictures on a hard drive you buy from Best Buy. You'll lose some fidelity if you compress them so you can show them on a forum like this. . .but the images displayed on a monitor are not what you'd really be comparing anyway. But I think a viewing a compressed version on an Internet forum has value. . .you just have to not store your references as compressed files.

Further, I think calibration is an extreme step that is only going to get you an insignificant increase in consistency. But if you want others to trust your results, you probably need to do it.

I do not agree that technology makes color ID harder. . .it makes it easier, or at least ore consistent.

Ok, I give up, you are right and a master colorist and expert technologist.
Don

I would like to add a few discussion points to the issue of scanning for color analysis.

A scanner needs to be calibrated.

Scanner output will vary over the life of the light source. So recalibration on a regular basis is necessary.

How does the light source on a scanner compare with indirect north light (or some other "natural" light source?)

It is not possible to compare the color of an actual stamp with an image on a monitor. One is reflected light, the other emitted light.

Are red/blue/green LEDs on one monitor the same hues (emit the same wavelengths) as on a different monitor? (not talking about calibration)

Measuring the color with a digital sampler is the way to go. That eliminates monitor calibration.

I have lots of stamps that have identical color under visible light but completely different under longwave UV light. So the question "do these two stamps have the same shade?" becomes much more complicated.

Attached is the joint issue of the 1986 Liberty stamps, one from the USA and one from France (not my image). See the different blue shades? The inks are identical; the difference is in the pressure from the press. Just one more complication in the world of color.

Don't blame the catalogue publishers, thank specialist collectors that first studied the stamps. It is the natural evolution of our hobby to focus on every detail. The catalogue listings that some despise are a natural outgrowth of discovering and collecting those items. It is the small detail and all of the challenges that make it fun and interesting.

collectors habits influence catalog makers decisions as to what to list. I agree focus on detail is and will always be a challenging part of the hobby. that said I would prefer less emphasis on shade variety's and more on making the catalog more inclusive of other unlisted issued items, especially in the revenue areas.