Canada #571ai, 573avar, 575aii, and 577avar 1974 Pacific Coast Indians Issue and 1975 Subarctic Indians Issue, Four Upper Right Inscription Blocks, On Either the Scarce HF Backs or Unlisted Variations of the Basic Papers, All VFNH

Four VFNH upper right inscription blocks printed on the scarcer HF backed paper, which is really more of a pure hibrite, as discussed below, and two unlisted variations of the basic issues as follows:

• The thunderbird Pacific Coast block is on a dull paper that reads as LF or MF, due to the inclusion of both MF fibres and woodpulp fibres, that together make the paper appear brighter than it usually does. This stamp is typically found on a similar paper, but the number and brightness of the fluorescent inclusions is usually much less.
• The subarctic thunderbird block is an MF/HB paper, rather than the normal HF/HB paper as discussed below.

All of these paper types are much scarcer than the usual paper found on these issues.

Unitrade cat. for all four blocks is $21.50, counting the two variations above as just basic blocks. So the actual value should be higher. These blocks grade between 80 and 84.

A Note About Paper in the 1972-1977 Period

The stamps during this period are printed primarily by Ashton Potter and BABN, and occasionally CBN. They used seven main types of paper, all of which, with the exception of the transparent HB paper, and uncoated CBN paper are chalk coated. The seven types are:

• A ribbed paper, that tends to be dull or non-fluorescent on the front, and varies widely on the back, from dull fluorescent with very few low fluorescent fibres and brownish woodpulp flecks, to a much higher concentration of low and medium fluorescent fibres and brownish woodpulp flecks. This paper usually reads overall as DF or LF, and occasionally as MF. This paper is used by BABN for the stamps printed by engraving and photogravure.
• A smooth paper that tends to be NF, DF or LF on the front, but on the back can be similar to the above paper on the one hand, or can be completely without any woodpulp fibres or inclusions. Usually the issues from 1973 to 1975 will contain fibres and inclusions that determine the overall brightness of the paper. From 1975 to 1976 the paper tends to have almost no inclusions and varies from NF to DF to LF to MF and finally to HB. This paper is used by BABN for the stamps printed by engraving and photogravure.
• A smooth paper with a thinner and shinier chalk coating that was used by Ashton Potter for the lithographed stamps. This paper varies very widely and Unitrade's descriptions are hard to follow, largely because most of the variations have, until very recently been unlisted. The front fluorescence van vary fron NF all the way up to HB, and the back, also tends to start at LF and progress all the way to HB. Distinguishing these though can be very difficult without comparison copies, for they all look HB when compared to say a stamp from the 1960's. However, when you compare them to other stamps of the same issue they are night and day. As a result, many of the better listed varieties are often misidentified. These papers will also often contain woodpulp fibres that will act to dampen the overall perceived fluorescence level, and occasionally fluorescent fibres will be visible as well. Issues from 1972 to 1975 tend to be HF, HB or MF, while starting in 1975 we see NF, DF and LF more commonly.
• A vertical ribbed, thin, smooth chalk-coated paper similar to the above paper, again used by Ashton Potter. I have only seen this paper so far on the 1975 Water Sports semi postals, but it may exist on other issues as well. It is very HF on both the front and back.
• An uncoated paper used by CBN for the Summer and Winter sports issues of 1974. This paper varies from DF to what Unitrade calls HB, but which is really just MF. Fluorescent fibres and woodpulp flecks are usually visble in this paper under UV.
• A medium, chalk coated paper, supplied by Abitibi-Price, that tends to be DF and tends to contain any number of LF and MF fibres. Unitrade often describes this paper as DF, and it can indeed be DF with no fluorescent fibres visible, but it can also include a lot of LF and MF fibres as well. Generally if the paper still reads overall as DF or NF, then it will be considered a variation of DF. Once it reads as LF, then it moves into that category. However, there may be 2-4 sub-types of each of these types of paper.
• A thin, crisp coated paper that was used by CBN for the 1976 Coastal Vessels issue. This paper can be found either DF on the front and back, NF on the front and DF on the back, or NF on both the front and back.

As you can see great care has to be taken to properly identify papers during this period. It must be appreciated that the terms NF and DF are not interchangeable. DF is a dull bluish or greyish white that lacks brightness, but still emits a very low level of light under UV. NF on the other hand must appear either deep violet, deep grey or deep blue and not be reflecting any, or very little light.