Australia #367-373 (SG#363-369) 6d to 3/- Birds 1963-1966 Definitive Issue, A Specialized Lot of 10 VF Used Stamps
A primarily VF used group of 10 stamps, comprising most all listed varieties of the 6d-3/- bird stamps from the 1963-1966 issue, including Helecon paper printings of the 6d, 9d, and 1/6d.
The Australian equivalent of tagging is called Helecon, which is a chemical in the zinc sulphide group that fluoresces orange-red under long-wave UV light. The very first stamp to be issued with Helecon coating applied to the paper was the 11d Rabbit Bandicoot from the 1958-1964 definitive issue. Later, the 5d orange-red Queen Elizabeth II stamp from this issue was issued with the Helecon incorporated into the ink. By the end of 1965 all stamps issued had Helecon applied to the paper.
The comparison picture shows the difference between the normal fluorescent paper, the Wiggins-Teape paper, which appears dead and the Helecon papers, on some mint stamps of this issue. The greyish stamps under UV are the Helecon papers. They appear this way because the Helecon has been impregnated into the paper, rather than coating the surface, so the red-orange is much less obvious and only really obvious under a loupe.
Gibbons lists the basic stamps at 20.70 pounds (approx. $41.40) for VF used. The stamps here grade between 70 and 80.