Newfoundland 124B Prussian Blue

has anyone read the
THE NEWFOUNDLAND NEWSLETTER
OF THE NEWFOUNDLAND STUDY GROUP OF BNAPS
Number 178 January-March 2020

it goes into great detail about the aniline ink variety.

From the Newsletter!!
"In summary then, this research did not show a difference in the pigment chemistry of the Prussian Blue certified copies and the other copies. There are minor differences in shade due to pigment particle size, a physical effect."

Trodent

Yes--I have read it. I also attended the presentation of the data a year ago at BNAPs annual convention in Ottawa by Judge.

As I politely stated above--I would not trust or rely up any certificate from anyone from any year regarding the color variety of any stamp of Newfoundland (and probably Canada too).

https://gupea.ub.gu.se/bitstream/20..._26820_1.pdf
Don

Stamps this old have survived a wide variety of environmental conditions. They've also been handled and preserved in different ways and again under different physical conditions. In short, different examples are probably in different physical shape. Does that make any difference in spectrographic analysis? If, e.g., two stamps, 100 yrs old, are supposed to be blue-green, but one is mint and the other postally used, soaked, and stored in various albums at various times & places, would they still graph the same? And if not, what then?

Interesting topic,TomSwift
I found interesting information on wikipedia.
Several methods of production and precipitation lead to different shades even if the chemical composition is the same.
Because it seems to have been used in Germany, I used German stamps registered in Michel in blue and Prussian-blue.
It's an obvious difference, but on my mini-microscope the 2 frames of the stamps don't look so different anymore.
It is observed (I'm sorry, not very successful pictures) the difference in size of colloidal particles that causes the difference between blue and Prussian-blue.

I have always thought that stamps were described as Prussian Blue because they appeared to be a similar colour to the Prussian Blue as described in Wikipedia above NOT that they had a similar chemistry.

As the Wikipedia article says that the physical form of the pigment particles has a huge effect on the colour as perceived by the eye.

I have never understood why collectors and dealers get so worked up about the shades of stamps that were printed some 100 years ago when there is no way of knowing what they looked like fresh off the press.

Amen!! But the catalogues force us, willy-nilly, into these torturous considerations of hue and shade, because catalogues assign different numbers to them, and often different values. And we feel compelled to follow the catalogues' lead.

Example: For British India, KGV 2a definitive of 1911, Stanley Gibbons invites us to decide between purple, reddish purple, deep mauve, and bright reddish violet (SG 166-9). For the 8a, 1911-2, we must choose between deep magenta, deep mauve, bright mauve, and purple (SG 179-82). And so forth. This for stamps over 100 years old, often postally used, and surviving through all sorts of different conditions. But we must try to decide, because we want to identify our stamps correctly and the catalogues assign different numbers, and sometimes significant valuations, to those color options.

Sorry for this somewhat off-topic to rant, but I'm getting impatient over the time spent considering these increasingly subtle differences of hue and shade on such old and well-handled pieces of colored paper. Especially since, color perception varies from person to person, and we don't (and may never) have access to the type of machinery that expertizers and research foundations have.

I have the Lighthouse Canadian Provinces stamp album and some of the variations in it puzzle me. Unfortunately I don't have it handy right now but for Provinces like PEI, they have spaces for colour variations I can't even find in the stamp catalogues. Same with the other provinces. After reading this topic, I have decided to fill these spaces with the same stamp or a proof if one is available. I am a completionist but this is going too far.

Incandescent lighting was not in wide use before 1887. Modern fluorescent lamps were not in widespread use until 1936. Compact fluorescent lamps came into use around 1977. LED came onto the scene around 2000 and are now in wide spread use.

Since color are wholly dependent upon the ambient lighting, it is little wonder why people who work in stamp colors largely ignore discussing ambient lighting.

No intelligent person would think that the same stamp viewed under a century of different lighting would appear to be the same color. Add to this the fact that inks and pigments change color over time and the challenges of stamp color is apparent.

And of course sight (including color perception) is a sense. Imagine trying to classify stamps by another sense like the taste of the gum. Why not? Perhaps there were different gum formulas used over time, classifying stamp by different gum formulas is not much different than classifying them by ink formulas.
Don