Is This 6c Garfield EFO Or Common? Bicolor

Thanks for any input

Welcome,
The discoloration can occur when a stamp is exposed to sulphur, a common chemical element present in many substances. When exposed to it, the color of the stamp can be dramatically altered into a much different and/or darker color. As with your stamp, this is most often seen is an orange or yellow stamp that has turned brown-color.

This sulphurization can be reversed with hydrogen peroxide.
Don

Whats called a changeling. Colour is changed due to exposure to light or some chemical. But welcome to the forum, just the same!

Unfortunately, not an error. Actually, it's a defective stamp. Sulfur ions in the atmosphere are reacting with the orange pigment, turning it brown. A soak in 3% hydrogen peroxide solution for a minute or two, followed by a water rinse will reverse the effect.

Robert

Thanks so much for the information #127995;