Amongst some written up pages of cylinder blocks purchased some time ago from a well known dealer, there is a 2½d 2 dot A36 and Bar cylinder block, the write up for which says 'during the final printing a subtle change of paper and ink gave rise to this 'Golden Blue' shade. The colour of the block is certainly different to any other examples I have seen and appears to have a small yellow element in its make up.
Does anyone know if there is any substance to the claim in the write up? I doubt if a scan would help although I can provide one if necessary.

Mike,
I have a fair number of 2½d values, perhaps if you were to scan the 'Golden Blue' alongside a normal it would show the difference.
Regards
Ron.

Mike,
Further to my posting - I have checked the cylinder blocks and sheets I have and can find nothing that looks like the shade you describe.

There is no mention of anything of this type in the King Edward VIII by Lt-Col J.B.M. Stanton published by the GBPS, nor in the KEVIII by A.J.Kirk, also published by the GBPS.

In the booklet The Postage Stamps of King Edward VIII by F. Hugh Vallancey, under "Varieties" there is this piece -
Quote:-
Examples of imperfectly printed stamps have been found, mainly due to imperfectly mixed ink or extra speed of the machinery.
Unquote.

There is no mention of anything similar in the S.G. 'Four Kings' Eleventh edition either.

Sorry I cannot help more.
Cheers
Ron.

Ron,
Thank you for your helpful response. A scan of the shade with a normal is attached. The shade is on the right.
Mike

Dear Mike,

Looking at my blocks today I was unable to detect any difference in colour of inks, but paper seemed to vary quite a bit, both in tone and thickness. Unfortunately I don't have a colour analyzer for the computer... but I scanned three blocks to show a selection. Once on white and once on black. I'm wondering whether the paper has more influence on colour transmission than we think.
Incidentally I had operations for cataracts last year, and colour perception varied from one eye to the other, it is better now but again, I'm wondering whether our own perceptions of colour vary.

Good luck anyway, Robin

Robin
Thanks for your assistance. You are correct in that the paper colour and thickness affects the shade of the stamp. Will have to keep on looking for an explanation.
Liked your scans. Pity the encroachment on the bottom one is not quite perfect.
Regards
Mike

Dear Mike,

I finally figured out how to use the computer to tell differences in colour. The following is superficial, but is certainly encouraging...

I tested the blue beneath the price tablet, beneath the crown, and on the side of the king's nose, plotting each probe, so there are four spots for each of the three locations. The two blocks are different - slightly.

I then checked the percentage of yellow showing at each of the three points.. below the price - the left side block shows 13 to 14% yellow on the side of the nose, 6 to 9% yellow below the crown, and 1 to 6% below the price.

In comparison, the right side block shows 19 to 21% yellow on the side of the nose, 12 to 16% below the crown, and 10 to 14% below the price. This seems to support the dealer's claim for a touch more yellow in the ink, and the sobriquet "Golden Blue". But...

Thankfully the two pieces you showed are marginal, and I was able to take three good tests of colour of the paper from each. Ready? The block on the left, which consistently showed less yellow in the stamp, showed variable yellow - of 24 to 25%. The golden blue block showed a solid and even 28% yellow in the paper.

I can draw the plotting and give you all the data if it's a help, just email me your address off-site:

So whatever the reason, your golden blue block is genuinely slightly different!

Best wishes,

Robin