So according to Scott, colors other than listed are considered essays. A couple of questions - I know nothing about these.... The new ones I have are to the right, pre-existing to the left in each picture. Sorry for not scanning, could not get album in scanner!!
For this 1st one, Sc300, the papers seem to be different. But I do not see these to be printed on different papers. Forgery? The one on the left the paper seems rougher and not as refined as the one on the right. And the one on the left is in orange - Essay?

This one is Sc303. Again - left one pre-existing right one new to me. Scott lists color as violet & pale lilac, which I presume is the one on the left? The one on the right an essay? The papers seem to be the same.

Lastly, Sc304 - left one pre-existing, right new to me. Scott lists color as dull blue & pale blue which is on the left? Right one essay??
