Looks like it was dipped in some kind of chemical that bleached out the base color.
Thank you for your answer, but I see that crease on the back that corresponds to the missing part of the color, then in other parts of the perforation it also lacks a little color, the white in the back part has not undergone color variation.
Sunlight?
Maybe a scrap of paper got between printing plate(s) and printing paper or was attached to the latter, and fell off later. To me, the crease does not correspond to the missing color - it would have to be inclined the other way to do so.
I had some envelopes sitting on a shelf for a number of years. Sunlight could shine on them. On the top envelope the Thai definitives changed colour. The envelope under the top one had just part of the stamp exposed and the colour change showed a similar straight line change on the part exposed. I will dig them out and scan them again. They were my party trick at stamp club meets.
Found them. Here we have three envelopes that were on a sunny shelf for a long time. The one on the left was covered by other envelopes. The one in the middle had the right stamp exposed to light and the last one was on top of the pile.
(The circular date stamps are not 1956 and 1957, but are the Thai Buddhist years 2556 and 2557, the equivalent to 2013 and 2014.)
"To me, the crease does not correspond to the missing color "
Any ideas why the color is different on this Navajo art stamp?
The stamp on the right has probably been exposed to sunlight for a longer time. Red inks often fade under such conditions.
-jmh
Have a nice day. I would like a clarification on this stamp for that fold in the back of the stamp, which corresponds to the lack of color of the opposite side of the stamp. Could you kindly help me to understand what was the cause of this anomaly ?.
re: Help to understand lack of color.
Looks like it was dipped in some kind of chemical that bleached out the base color.
re: Help to understand lack of color.
Thank you for your answer, but I see that crease on the back that corresponds to the missing part of the color, then in other parts of the perforation it also lacks a little color, the white in the back part has not undergone color variation.
re: Help to understand lack of color.
Maybe a scrap of paper got between printing plate(s) and printing paper or was attached to the latter, and fell off later. To me, the crease does not correspond to the missing color - it would have to be inclined the other way to do so.
re: Help to understand lack of color.
I had some envelopes sitting on a shelf for a number of years. Sunlight could shine on them. On the top envelope the Thai definitives changed colour. The envelope under the top one had just part of the stamp exposed and the colour change showed a similar straight line change on the part exposed. I will dig them out and scan them again. They were my party trick at stamp club meets.
re: Help to understand lack of color.
Found them. Here we have three envelopes that were on a sunny shelf for a long time. The one on the left was covered by other envelopes. The one in the middle had the right stamp exposed to light and the last one was on top of the pile.
(The circular date stamps are not 1956 and 1957, but are the Thai Buddhist years 2556 and 2557, the equivalent to 2013 and 2014.)
re: Help to understand lack of color.
"To me, the crease does not correspond to the missing color "
re: Help to understand lack of color.
Any ideas why the color is different on this Navajo art stamp?
re: Help to understand lack of color.
The stamp on the right has probably been exposed to sunlight for a longer time. Red inks often fade under such conditions.
-jmh