Canada #535 6c Multicolored Spring, 1971 Maple Leaves, 8 VFNH Inscription Pairs On Different HB/HF, HB/HB, HF/HF & MF/HB Horizontal Ribbed Papers

8 VFNH inscription pairs of the 6c multicolored Spring from the 1971 Maple Leaves on different HB/HF, HB/HB, HF/HF & MF/HB horizontal ribbed papers. The lot includes;
• HB12/HF9
• HF9/HF9
• HF9/HF8
• HB11/HB11-fl
• HB11/HB10
• HB10/HB11
• HB10/HB10
• MF7/HB11

Unitrade values these at $6.4. The stamps offered here grade between 80 and 84 as follows:

Centering/Margins: 50/70, 54/70

Paper Freshness: 5/5

Colour: 5/5

Impression: 5/5

Absence of Visible Paper Flaws: 5/5

Perforations: 10/10

This issue continues the use of 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.