Phosphor printed on both sides.

Anything to do with the Machin definitives issued from 1967 to 2022.
Post Reply
Saffron Machin
Posts: 1
Joined: Fri Feb 19, 2016 11:42 am
Location: Saffron Walden
Contact:

Phosphor printed on both sides.

Post by Saffron Machin »

The above error appears several times in Gibbons' Vol 4 Part 1, and is usually associated with booklet panes, especially Prestige panes.
Is the phosphor under the gum and if so is it detectable under a UV lamp?
If over the gum is it still detectable?
I have several Prestige Panes where it appears that you can see phosphor bands on the back, but there is no reaction under UV. Perhaps there is a strong application on the front that can be seen through the pane, and only appears to be both front and back phosphor?
Any help in methods to establish this error appreciated.
Post Reply