Lot 125 Canada #533var 6c Multicolored Laboratory Equipment, 1971 Discovery Of Insulin Issue, 2 VFNH Singles On MF7/HB12 & MF7/HB10 Papers With Minor Rightward Shift Of Blue Color

2 VFNH singles of the 6c multicolored Laboratory Equipment from the 1971 Discovery Of Insulin Issue on MF7/HB12 & MF7/HB10 papers with minor rightward shift of blue color.

The minor rightward shift of blue causes the inscription 'Insulin Insuline 1921' to appear blurry, the blue highlights in the test tubes to appear just to the right of them.

Our best estimate of the value, based on the Unitrade price for normal stamps, and the types of premiums usually awarded by them for the vartieties it does list is $10. The stamps offered here grade 84 as follows:

Centering/Margins: 54/70

Paper Freshness: 5/5

Colour: 5/5

Impression: 5/5

Absence of Visible Paper Flaws: 5/5

Perforations: 10/10

The Insulin issue introduces a new type of paper, which is chalk-surfaced, and either horizontal, or vertical wove. It usually has clearly visible mesh, which resembles ribbing. So, I tend to call it horizontal ribbed, even though the surface of the paper is smooth. The fluorescence readings on this paper are nearly always different on the front and back, and the gum is usually a very matte PVA that has very little surface sheen.

In describing fluorescence on these issues and all the stamps issued after 1970, it is critical to understand the Irwin-Freeman scale of fluorescence, which ranges from 0 to 12 and that a particular designation like say HB or HF will correspond to more than one fluorescence level. One pitfall that many collectors fall into is to compare the papers, rank the fluorescent reactions from low to high and then try to force them into the DF/LF/MF/HF and HB nomenclature, rather than recognizing that three different levels of reaction may actually correspond to the same designation. This is why Unitrade's listings for this period are so confusing. Generally HB corresponds to levels 10 through 12; HF, levels 8 and 9; MF, levels 7 and 6; F, level 5; LF, levels 3 and 4; DF, levels 1 and 2 and finally NF corresponds to 0.