Post by angore on Jul 12, 2020 17:25:44 GMT
I have been studying OCP (original coated paper) vs fluorescent coated paper. The FCP type is noted to have a stronger response under shortwave.
The one on bottom row would be the FCP with the top row OCP but the one on the end could be questionable. The response from used stamps is degraded from unused.
The one on bottom row would be the FCP with the top row OCP but the one on the end could be questionable. The response from used stamps is degraded from unused.