


Could be these SG numbers, depending on the cover bird.
QP38 June 1968 Kingfisher
QP39 July 1968 Kingfisher
QP40 Aug 1968 Peregrine Falcon
The above all had 2 phosphor bands.
QP41 Sept 1968 Peregrine Falcon
QP42 Oct 1968 Pied Woodpecker
QP43 Nov 1968 Pied Woodpecker
QP44 Dec 1968 Great Crested Grebe.
These all had one centre phosphor band.
There were previous issues of the 6/- booklet without birds numbers QP32-37.
Edit, Sorry just realised I did not read your question fully. The May 1968 number is QP36, Claret cover with GPO cypher.
Hi QP36 is correct however there is a QP37 which has PVC gum the reference number I indicated may be the QP37 just not sure, need to know how to decide on the gum used
Rich
Rich, if I recall correctly the pva gum has a slight bluish green tinge.
Yes the pva gum is QP37, the gum arabic being QP36.
That is a good thought shall try and see if that colour shows or not.
Rich
Here is the section from SG Concise relating to gum on the early Machins. The tinge apparently is yellowish not bluish.
Not sure this helps at all or just makes things more confusing.
Hi I get the picture might be or might not be the sad part is the extreme values of the different gums with the Machin booklets,anyway thank you for your interest in this thorny problem.
Richard
Recently purchased a set of GB booklets all on pages identified I believe by the Michel Catalogue one which has the number 0-64a 1X can anyone let me know what this might be re SG
thanks
Rich

re: GB 6/-Booklet May 68
Could be these SG numbers, depending on the cover bird.
QP38 June 1968 Kingfisher
QP39 July 1968 Kingfisher
QP40 Aug 1968 Peregrine Falcon
The above all had 2 phosphor bands.
QP41 Sept 1968 Peregrine Falcon
QP42 Oct 1968 Pied Woodpecker
QP43 Nov 1968 Pied Woodpecker
QP44 Dec 1968 Great Crested Grebe.
These all had one centre phosphor band.
There were previous issues of the 6/- booklet without birds numbers QP32-37.
Edit, Sorry just realised I did not read your question fully. The May 1968 number is QP36, Claret cover with GPO cypher.
re: GB 6/-Booklet May 68
Hi QP36 is correct however there is a QP37 which has PVC gum the reference number I indicated may be the QP37 just not sure, need to know how to decide on the gum used
Rich

re: GB 6/-Booklet May 68
Rich, if I recall correctly the pva gum has a slight bluish green tinge.
Yes the pva gum is QP37, the gum arabic being QP36.
re: GB 6/-Booklet May 68
That is a good thought shall try and see if that colour shows or not.
Rich

re: GB 6/-Booklet May 68
Here is the section from SG Concise relating to gum on the early Machins. The tinge apparently is yellowish not bluish.
Not sure this helps at all or just makes things more confusing.
re: GB 6/-Booklet May 68
Hi I get the picture might be or might not be the sad part is the extreme values of the different gums with the Machin booklets,anyway thank you for your interest in this thorny problem.
Richard