Brown Vs Yellow Color Variety Or Color Changling Or Color Error? 10cent Monroe

I know I am new so I will not post any more questions today . Everyone has been very kind and helpful so far. I have a "color oddity" on the common 10ct Monroe.
1) The color seems consistent across the stamp (not like some changlings with light etc., or chemical issues).
2) The back and edges seem to be "normal paper while/beige color" so what ever changed the stamp's color (if it was changed), only affected the color yellow on the front.
So could it be a color error/freak or oddity ... etc. Thanks in advance!

Color error stamp is of course the "middle" one.

Hi mljespe. Your stamp looks like a changeling to me.


Peter

Thank you Peter for reply

Mljespe, you're welcome. I meant to also tell you that the two on the outside are also affected, especially the one on the right


Peter

For more on color changelings, see Stamp Smarter:

https://stampsmarter.org/learning/A...gelings.html

Air-born sulfur (likely source is hydrogen sulfide) is the likely cause of the color change which affects yellow pigments.

If you want to have a bit of chemistry fun on the USED copy, use some common peroxide on the stamp. The color will change back towards the original. Same can be done with a mint copy if a Q-Tip like device to apply a very small amount to avoid soaking the paper and thus disturbing the gum is used.

A Scientific Philatelic Warning Note:

During the building craze of the early 21st Century, lots of Chinese made drywall was imported. New buildings and remodel building (read homes) built from 2001 and onward with a real peak in 2006 and 2007 were build with Chinese Dry wall. In studies of the products from the Chinese sourced as compared to non-Chinese sourced (read American made) drywall were found to be out-gassing emission rates of hydrogen sulfide at 100 times the rate of non-Chinese drywall.

I know of one collector who did a repair in his stamp room which included new drywall who began to notice sudden color changing on his stamps. When I told him of the issue, he removed the drywall and sourced some non-Chinese drywall and replaced the problematic drywall.

This issue regarding drywall was studied by UC Berkeley's on campus LBL which was part of UCB until the feds demanded to take it over as they also did with UCB's LLL. You may Google to learn more about the study and (edit) SERIOUS damage caused by the unacceptable level of out-gassing of hydrogen sulfide.

Note: Before people panic and replace all of their drywall it should be noted that the problem involved approximately 250,000 tons of drywall in 100,000 structures mostly in Florida and the South. The importation was driven by the rebuilding in NOLA after Katrina. Many lawsuits have been settled. It was not a subtle problem. The smell from the off-gassing made many houses unlivable and the gasses corroded metal and HVAC systems. You would notice.

Other common environmental issues are much more likely to be encountered.

Thanks all for the information provided! Very helpful

Not the same stamp but here's a page that shows the variety of colors you can get with yellow or orange stamps;

https://i.ebayimg.com/00/s/MTYwMFgx...on~/$_57.jpg