Canada: 50c Centennial definitive colour error?

polarbear

Went through my 15 used copies and 1 Mint copy of 465A (brown orange) and could not find the darker shade variety you just showed us and I agree Unitrade 2020 does not describe it. I am sure we will have further comments from members !

René

Fascinating! It will be interesting to hear from the Canadian experts.  In any case, the color difference is sure dramatic.

It is so much darker - faded copies do usually seem lighter, don’t they? It is almost as if it got a double dose of black/brown. 

Besides some "changeling" I do not think we will find a "variety" for this Canada Stamp 


René

I've never seen this for the 50c stamp. As philatelia noted, the pic clearly shows a very dark brown and the design remains very sharp.

Scott lists the color as brown orange, which makes me wonder if it might be sulfur contamination? While I've seen this with certain orange shades, again I will note I have never seen this with this 50c stamp. Sulfur contamination will slowly chemically change certain orange pigments, so over time the orange color will darken. I don't know the ink used in the printing, so this is just a guess. Sulfur contamination only affects the very near surface of the ink, the underlying ink remains uncontaminated. You can convert the darkened surface layer to a very thin "transparent" layer by briefly dipping the stamp (don't soak for more than a minute, because it shouldn't take long) in very dilute hydrogen peroxide (only need a few %, like the kind you purchase to kill bacteria at the drugstore). As the surface layer becomes transparent, the underlying orange pigments will begin to be gradually visible. If it isn't sulfur contamination, the dark brown color will remain steadfast. If the color begins to slowly turn brown orange, then you have a color changeling. But remember, don't soak in hydrogen peroxide too long -- it will result in a bleaching effect if left in too long.

I don't do this for my stamps, so I'm not recommending this. And I would strongly suggest you await comments from other members before trying this.

Who know, maybe it really is an inking error that hasn't been reported. It's no fun if you can't dream big, right?

Hmm... hi everyone. I’m checking in having just come in from an evening at a friend’s. We have no hydrogen peroxide in the house apparently. We’ll all have to wait till tomorrow when I’ll go to the drugstore. Thank-you everyone for your input! I’m hoping to hear from more people overnight. 😊. I suspect it is nothing special. It probably came in a kiloware packet sometime in the ‘70s.

Okay everyone. I went and purchased 3% hydrogen peroxide. I watered it down to 1.5%. Here are the results. The upper stamp is still wet. I rinsed it with cold water after treating it with the peroxide mixture. I held the top half under the peroxide for ten seconds. Should I have held it under longer? I am concerned about the long term effects of the hydrogen peroxide on the stamp.

N.B.  Just gave it another rinse in cool soapy water and a final rinse in plain water.  No difference. 

😁 okay renden I’ll try it again!

read the link I added for you

René

The browning, possibly due to Sulphuration from the atmosphere, used to be a common phenomenon with penny reds and twopence blues from Victorian Britain, when homes were lit by gas light and houses had open coal fires, both of which released S02 and H2S into the atmosphere.

Gas lighting went out by WW2 or just after, and the Clean Air Act of the late 1960s saw the end of coal fires. This would be the first modern Sulphur affected stamp I have seen.

Thanks for allowing us to watch your progress on this, polarbear , it's been interesting!

Although I have seen plenty of sulphuretting on classic-era stamps, I hadn't really seen a lot of it on more modern era stamps, so I will admit that I was skeptical that yours would turn out to be sulphuretted in the end.  But the result is clear: when hydrogen peroxide can change the color, then it has clearly been sulphuretted (or sulphurized).

My pet peeve on this: most collectors carelessly use the term "oxidized" when they should say sulphuretted or sulphurized to correctly describe these color changelings.  Ironically, the process that you just put your stamp through using the hydrogen peroxide literally re-oxidizes the stamp, removing the effects of the sulphur and restoring the original color.  So, oxidizing or oxidation is actually the cure, not the problem.

But most collectors insist on calling their changeling colors oxidized instead of sulphuretted.... sigh.

This is an example of how having a degree in chemistry can sometimes lead to a bit of stress! 

Fascinating thread! Like an episode of Bill Nye the Science guy, heh heh? Color changelings are fun and add a bit of "color" to our collections (groan, bad pun!) 

I did learn something - which is why I read every post here in the Stamp Forum. I encounter something new almost every day it seems like!

Okay Here it is.  Sorry to take so long to post.  My V600 scanner wasn't working after the Windows 11 upgrade.  I've spent the last hour or so getting it to scan this!

Jean (polarbear), thanks for reviving this topic.  I have combined your recent posts into the original thread to keep all the information about your stamps in one place.

For my part, I am surprised to see that the color seems to have darkened again. I have not heard of that before in cases of sulfuretting, so I will need to think a bit about that.  If I come up with any insights, I will make another post.

Thanks again for your follow-up on this situation. Definitely intriguing!

renden , I noticed there was nothing in the Unitrade catalogue. I guess, if it’s a changeling, I’d like to know why. Or rather how. I may never know the answer, but wondered if any new information had come to anyone’s attention.

There was a man on stamp talks the other night - Garfield Portch - who used to work in the print shop where they printed stamps, I believe. Is he on this board? I was going to ask him last night, as they were talking about varieties, but they said everything was in Unitrade…and then said Unitrade wasn’t the only resource for certain stamp series (like the small queens). So I wondered if this was a case of Unitrade not being the only resource.

You know….I have the “centennial definitive series 1967 - 1973” book by Robin Harris. He should know if anyone does. The book says there were two “shades”: light orange-brown” and “dark orange-brown”. But doesn’t say anything beyond that. I don’t know if that’s just the colours of ink used on the stamps as a whole, or what.  I think I’ll explore the book a little more in-depth. It’s a few hundred pages long. Might be something there?