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Tuesday, August 15, 2017

The Gum Types On The 1967-1973 Centennial Issue

Overview

The topic of gum on the Centennial issue is one that has not received very much attention at all since collectors became aware of the basic difference between dextrine and PVA gums. However, like any chemical compound, the composition of the gum on this issue showed considerable variation as the post office experimented with different formulas as they transitioned away from dextrose gum towards synthetic PVA gum. Indeed the special hybrid gum, termed "spotty white gum" by collectors, that first appeared on a limited basis in 1971 was almost a cross between dextrose and PVA in the sense, that it had most of the properties of PVA gum, but it possessed much of the shine and thickness associated with dextrose gum. In addition to variations within the three major categories of gum, there was also a significant difference in the properties of the gum used by the British American Bank Note Company (BABN) on the stamps that it printed, and the gum used by the Canadian Bank Note Company (CBN).

This post will look at the the variations that can be found in each of the three major categories of gum: dextrose (dextrine), PVA and spotty white gum. I will attempt, where I can, to show scans of the various types. However, the scans will likely not show some of the attributes, such as sheen and streakiness. I will do my best to describe them in these instances.

In asserting that the appearance of the gum is a significant and collectible attribute, I like to draw an analogy between stamp gum and paint on a wall. Almost everyone is familiar with the different paint finishes available: high gloss, semi-gloss, satin, eggshell, matte and flat. Most will also realize that the different finishes are possible because of minute differences in the chemical makeup of the paint. I would assert that stamp gum is much the same: the degree of surface gloss, the texture, the colour, and how evenly it adheres to the paper when it is applied, are all attributes that will differ as the chemical composition of the gum changes, or its method of application, and therefore, significant differences in these attributes, are, in my opinion, different types of gum.

Dextrose (Dextrine) Gums

CBN Printings

The gum used by the CBN shows a considerable amount of variation, in terms of colour, texture, its streakiness and sheen.:


  1. One type is a very light yellow colour, that shows very small vertical or horizontal patches of thinner gum, arranged in a regular vertical or horizontal pattern. I have examined large multiples of stamps with this type of gum and can confirm that the streaky pattern extends across all stamps in a pane, so it does not represent a random variation in the gum, but rather a difference in appearance that arose as the gum dried after being applied. The sheen is generally a satin to semi-gloss sheen.
  2. A second type is a very light yellow also, with the same satin to semi-gloss sheen. Only this time, the gum is completely smooth and evenly applied, with no thin areas or patchy spots. 
  3. A third type is a deeper yellowish cream, with a semi-gloss sheen and a completely smooth surface. 
  4. A fourth type is a light cream, with a semi-gloss sheen and a completely smooth surface. It is the same as the third type, except for colour. 
  5. A fifth type is a light yellowish cream, with a satin sheen and a completely smooth surface. This gum has the appearance of being applied either by spraying or with a very fine roller, as it has a very fine, stippled appearance. 
  6. A sixth type is deep yellow, with a satin sheen and smooth surface. 
  7. A seventh type is also a yellowish cream colour and is both thick, and has a semi-gloss sheen. The key distinguishing characteristic is that it is highly mottled in its texture, looking like it was applied with a sponge. 
  8. An eighth type has the same satin sheen as the spotty white gum, except it is yellowish dexrose gum, quite clearly. It has a completely smooth surface. 

The scans below show some of the above types of gum:


The above coil block shows the first type of streaky dextrose gum. The streaks are a little difficult to see at first, but if you stare at the block for a few minutes and allow your gaze to relax somewhat, you should able to see that the gum colour is not even: there are very small spots of lighter colour. These spots are the streaks. 

Here is an example of the same gum on a plate block of the 10c Jack Pine, showing the streaks running in the horizontal direction:


Finally, here is a third example, which shows much more prominent streaks in the gum. This example is a plate block of the 2c totem pole:


Here, you can see the uneven colour of the gum very easily. 



This coil shows the second type of gum. Note the light yellowish cream colour and how the gum on this stamp is completely even and smooth. 

I have prepared an overlay scan, where I place this stamp on top of one of the stamps in the above block to try and show the difference between these two gums a little more clearly:


The scan below shows an example of the third and fourth types of gum on two plate blocks of the 10c Jack Pine:



Here is an example of the fifth gum type, shown in the stamp on the left, next to the third type, on the stamp at the right:



Here is an example of the sixth type on a 1c stamp with Winnipeg centre bar tag:



As you can see, it is similar to types 2, 3 and 4, except that the colour is a deeper yellow. 

Finally, the seventh type is shown on the following plate 4 block of the 1c:


Again, if you look carefully at this gum, you can see that the colour is not completely even, but it is not streaky as the above examples of the type 1 gum are. 

Finally, the eighth type is shown on this 50c Summer's Stores on the scarce hibrite paper:



This scan clearly shows the strong vertical mesh that is present on the paper used to print this stamp. However, not all HB stamps look like this. I have other HB examples of this stamp that show no mesh and have types 2, 3 or 4 gum. 

I have seen types 1 through 6 on all printings from 1967 to about 1970, so these were used throughout the period that dextrose gum was in use. Type 7 seems to occur mainly on printings from 1970, like plate 4 of the 1c, and 5c for example. I have only seen the type 8 gum on the 50c Summer's Stores printed on HB paper, but I suspect that it exists on the other CBN high values on HB paper as well. It looks like a transitional gum that was used in 1971 just before the spotty white gum was introduced.

BABN Printings

The gum used by the BABN on the 4c carmine, 5c blue, 6c orange, 6c black, 7c emerald and 8c slate varies in colour from a very light yellowish cream to a pure white. So it is almost always much lighter than the gum used on the CBN printings. It is never streaky, always being smooth and completely evenly applied to the stamp. However, I have seen three distinct types that vary, both in terms of the sheen and the overall texture, as follows:
  1. One type, is very shiny, being a high gloss sheen, and it has very light horizontal streaks, having the appearance of being brushed on. The streaks are quite light, but once you see them, they are quite obvious. I have seen this type of gum on all six denominations. In terms of colour, this gum is usually either a very light yellowish cream or a pure white.
  2. A second type, which has a semi-gloss sheen and appears completely smooth. Thus gum is a very light cream colour. 
  3. A third type is a cream colour, has a satin sheen., and is completely smooth. Under 10x magnification, a clear diagonal crack pattern is visible in the gum. 
The scans below show two blocks of the 6c orange, perf. 12.5 x 12, with the first two types of gum:



This is the high gloss gum with the horizontal streaks. They are difficult to see, but if you look carefully at the top selvage of the block, you can just see them.



This is the semi-gloss gum that is completely smooth, with no streaks.

The third type of gum seems to occur mainly on printings of the 1c, 6c, 4c and 5c booklet stamps, and is shown in the following scan of a 1c pair taken from the 25c booklet:


Here you can see the diagonal pattern of fine cracks, right from the high-resolution scan.

PVA Gums

CBN Printings

The PVA gum most commonly seen on the stamps printed by the CBN is a light cream colour, is completely smooth, and has an eggshell sheen. Under magnification, more of a sheen is visible, and it is possible to see very fine cracks in the gum, however, when viewed normally, the gum is completely smooth. The gum is a thin gum, as its application does not alter the surface texture of the paper in the way that the BABN gum does. The BABN gum has a completely smooth and solid appearance, even under magnification, whereas with this type of gum, the natural rough texture of the stamp paper is still visible underneath the gum, as the gummed paper appears somewhat rough under magnification.

The scan below shows an example of this gum on the 2c totem pole:


Note the smooth appearance, and the rough texture of the surface. The colour appears quite white when viewed alone, or in comparison to the dextrose gums. However, when compared to the pure white of card stock, it is actually quite creamy and off-white.

There are actually two types of this gum, that only differ in terms of the overall sheen. The first has the usual eggshell sheen with a slight shine when the stamps are viewed at an angle to the light. The second has a matte sheen, even when viewed at an angle to the light. The scan below shows both types on two different 1c stamps, with the eggshell stamp on the right, and the matte stamp on the left:


As you can see, these types are almost indistinguishable from the scan alone. However, you may notice that the gum on the right stamp (eggshell stamp) is slightly thicker than the matte stamp. The paper is also different, with the right stamp being printed on a vertical wove that shows clear vertical mesh when viewed against strong backlighting, and very light ribbing on the surface, when viewed under magnification. The perforations tended not to punch out fully on this type of paper and gum, so quite often you will find stamps with this gum having unpunched perforation discs adhering to the stamp, as in the above example. 

Here is a scan showing the two types of PVA gum on the 10c Jack Pine:


The matte gum is shown on the top stamp, while the bottom two are the slightly creamier eggshell PVA. 


BABN Printings

There are three main types of PVA gum found on the BABN stamps that were produced in booklet form. The main points on which the gum varies are the colour and they surface sheen:

  1. The first type is a pure white colour, completely smooth and possesses a very slight surface sheen. It is too matte to be a satin sheen, but it is shinier than what we would normally think of as an eggshell sheen. 
  2. The second type is a cream colour, completely smooth, and has a satin sheen, being much shinier than the first type above. This type is found on the stamps from the $1 integral booklet issued in 1971-1972.
  3. The third type is also a slightly deeper cream colour, completely smooth, but has the same sheen as the first type. 

The scans below show these types:


This is the first type of gum, on a pair of the 7c taken from a 25c booklet from 1971. 



This is an example of the second type on a block of 6 1c stamps taken from the large $1 integral booklet issued in 1971-1972. The difference between this and the first type above, is not obvious from the scan, but the colour is clearly different, as the overlay scan shows:


Hopefully, you can see from this scan that the first type of gum is clearly whiter than the second. 

The third type of gum is shown in this comparison scan, with the third type being laid on top of the above pair of the first type:


The cream gum is shown on the bottom, while the white gum appears on top.

Spotty White Gum (CBN Printings Only)

The spotty white gum is actually a sub-type of PVA gum, being a streaky PVA with a semi-gloss sheen. The term "spotty" refers to the streaks that can often be seen in the gum, which result from tiny patches where the gum is thinner than the rest of the stamp. This type of gum is so far only known on certain printings of the 10c Jack Pine, made between 1971 and 1972. That this type is not known on the other values is a mystery, since they were all continuously printed in 1971, and common sense would suggest that the other values should exist with this type of gum as well. However, no examples have been reported on any value other than the 10c. There are slight variations in the surface sheen, from satin to semi-gloss, but all of the stamps I have looked at with this gum, have the gum quite white in comparison to the other gums discussed here.

The scan below shows two examples: one on a Winnipeg tagged stamp, and the other on an untagged stamp:


The streakiness of this gum is not visible from the scan at all. However, what is visible here is the distinct vertical ribbing of the paper on which this gum was used.

Conclusion

This concludes my discussion of the different types of gum found on this issue. Clearly there are some very major differences other than just the distinction between dextrose and PVA. Undoubtedly, there are many stamps from this issue which will likely only be found with the one gum type. However, there are many others that likely exist with three or four different varieties of dextrose gum, and many of the PVA gum printings probably exist with more than one type as well. I already gave one example: the 50c on HB paper, where I have seen two radically different types of dextrose gum and paper. So this is clearly an aspect of this issue that is more deserving of detailed study to establish, once and for all, what all the different gum types are, and which printings exist with which type.

Next week's post will look at the different types of ink that were used to print the stamps. 

Tuesday, August 8, 2017

The Papers Used To Print The Centennial Definitives - 1967-1973 Part Two

Today's post will tackle the aspect of this issue that has probably received the most attention from specialists of this issue, and is definitely the most fun, but also the most confusing: the paper fluorescence. The study of paper fluorescence has been a "thing" since Irwin, Keane and Hughes, and Gronbeck-Jones published articles about this topic in the 1960's when the issue was current. However, it was, until relatively recently a fringe topic that was well outside the scope of even the Canada Specialized catalogue. I can well remember when I was a child in the early 1980's that the only paper varieties listed for this issue were plain paper and hibrite paper. However, since the late 1980's the topic of paper fluorescence has received more and more attention from mainstream philatelists, and consequently, the number of listings in the Unitrade specialized catalogue has grown considerably.

Despite this expansion in coverage, there is still, in my humble opinion, much inconsistency in the descriptions of papers, as well as some confusion when it comes to describing fluorescence levels. There are also other instances where very subtle, but real varieties are getting overlooked because the current nomenclature to describe the papers cannot accomodate the varieties, so that they get lumped in with other paper types.

The tricky part to today's post will be getting illustrations of the varieties that show the fluorescence well. Because I have to use my ultra-violet light to show the paper types, I cannot use my scanner, and have to rely instead on my digital camera. This does not have the best resolution, but I will try to take the best pictures that I can, and hopefully they will be of sufficient clarity to illustrate what I am talking about here.

Points of Confusion in Describing Fluorescence and Attributes

As my pictures will show, the nomenclature in Unitrade that has been used to describe fluorescence is confusing because quite often two very similar stamps will be described differently, while the same basic descriptor, such as "F" for fluorescent, LF for low fluorescent, or HB for hibrite, can look very different on different stamps. This is not a desirable state of affairs for someone who is trying to properly classify their stamps, and who do not have the benefit of a large reference collection against which to compare their stamps. In any event, it should not be necessary to have such a collection on hand. A good system of nomenclature should enable a complete novice to properly identify and classify their stamps using straightforward descriptions.

Why does this confusion arise?

The main reason is that there are several dimensions to paper fluorescence:


  1. The brightness of the paper under long wave ultraviolet (UV) light.
  2. The colour of the paper under UV. 
  3. Whether of not the paper is of uniform, or compound fluorescence.
The problem with the Unitrade nomenclature that I see, is that papers are classified according to their overall appearance, and these three dimensions are all lumped together, so that where many papers would be described differently if all three dimensions were considered separately, they are all forced into the same general category. Let us consider what these dimensions actually are, and how they vary. 

Brightness of the Paper




The brightness of the paper refers to the light that is reflected back when the stamps are viewed under UV. Keane and Hughes had a numeric scale to describe this that ran from 0 to 10. This is useful for those philatelists who can compare and contrast different papers, but I very highly doubt that a novice, or even two experts would agree, for instance on the difference between say, a 3 and a 4 on the scale, or an 8 and a 9. So the numeric scale suffers from a lack of objectivity. 

Most philatelists use qualitative terminology to describe these different levels of brightness. The terms most commonly used are:

  1. Dead paper, which is at the lowest end of the scale.
  2. Non-fluorescent (NF) paper.
  3. Plain or dull paper (DF).
  4. Low-fluorescent (LF) paper.
  5. Medium-fluorescent (MF) paper.
  6. High fluorescent (HF) paper.
  7. Hibrite paper (HB), at the highest end of the scale.
The difficulty with these terms is how to apply them to classify a particular stamp. The above three pictures taken with my camera show the various levels of brightness and I will attempt to explain how one can get a sense for which fluorescence levels are which. I highly doubt that a complete novice will be able to easily distinguish between dead and NF or between MF and HF, or HF and HB. However, they should not have too much trouble identifying DF versus NF or dead, LF versus DF, and HB. With experience, you will begin to develop a kind of sixth sense that will allow you to tell when paper is LF, MF or HF, as well as the difference between NF and dead, or the difference between HF and HB. 

I prefer to start by considering what we are actually looking at when we view stamps in a darkened room under the UV light. The lamp itself emits a light purple coloured light, and in a darkened room, it is the only light source. So it may make sense to start by comparing how bright the paper appears to how bright it would normally appear in normal, incandescent, or daylight. Plain or dull paper, should, at its essence, be about as bright as paper would normally look in a room under low light, whereas fluorescent paper should always look brighter than this. Non-fluorescent and dead paper should look much darker than paper would appear under normal lighting conditions. Hibrite is reserved for the absolute brightest possible paper - it is so bright as to be a very bright white. So this explanation should help you sort your stamps into four groups:

1. Dead or NF.
2. Plain.
3. Low, or medium fluorescent,
4. High fluorescent or hibrite.

Once you have these four groups identified, you can sort them more finely to identify the finer differences.

The top picture shows dull fluorescence on the left, and high fluorescent on the right, with low and medium fluorescent in the middle. In the second picture, the two stamps on the left are low fluorescent overall, the middle stamp is medium fluorescent, while the stamp on the right is dull fluorescent. In the third picture, the stamp on the left is non-fluorescent, the middle stamp is dead and the right stamp is hibrite. 

Colour of the Paper

In addition to the brightness of the paper, there is also the colour. Some papers will appear violet, or light violet under the UV lamp. Others will appear greyish white, or greyish, while still others appear bluish white. Unitrade completely ignores this aspect of the paper, and there are many instances where there are several different papers, all of which are dull fluorescent, but which appear a slightly different colour.

The following pictures show some examples of these differences:


These 6c orange precancelled stamps are both on dull fluorescent paper, with the stamp on the left being greyish-white and the right stamp is greyish. Most philatelists would probably consider these to be the same paper, but to my eyes they are different. 


These stamps to my eyes are both low fluorescent overall, although Unitrade classifies the one on the right as medium fluorescent. The stamp on the left is dull bluish white while the one on the right is a clear bluish white.



The stamp on the left is on dull fluorescent paper, and is a pure white, while the stamp on the right is a deep violet - almost the same colour as the light itself. The stamp on the right is on dead paper. Interestingly, there is no listing currently in Unitrade for a 4c precancelled stamp on dead paper, which goes to show that while the Unitrade listings are extensive, they are by no means complete. 

Uniform Versus Compound Fluorescence and Naming Convention

This dimension of fluorescence is the most complicated of all. Uniform fluorescence is where the fluorescent reaction of the paper is of uniform colour and brightness across the entire stamp. The stamps in both the first and the third pictures above are uniform fluorescence, being either dull fluorescent or dead. Hibrite is generally a uniform fluorescence as well, as the reaction is the same across the surface of the entire stamp. 

Compound fluorescence on the other hand, is where the paper, in addition to having an overall level of fluorescence, contains a number of fibres embedded in the paper that fluoresce either a different colour, a different brightness level, or both. These first began to appear in papers starting in about 1962. What is confusing is that Unitrade has been completely inconsistent in their naming of these papers, while also being inaccurate in their descriptions. Usually, the overall fluorescence level of these papers would read as low fluorescent, but that would only be because dull fluorescent paper contained a sparse number of fibres that would glow either low, medium or high fluorescent, and it is the presence of these fibres in varying concentrations that gives the overall fluorescent effect. 

The picture below shows an example of this type of paper:


This picture shows the fluorescent fibres that are present in both papers. Both of these stamps are the 6c black transportation, printed from the CBN die. Ths stamp on the left is what Unitrade classifies as LF, while the stamp on the right is what Unitrade classifies as MF. The reality though is a bit more complicated. The stamp on the left does indeed read as a low fluorescent greyish overall, but there are MF fibres in the paper as well. There are a fair number of them, but they do not stand out much because they are only one level brighter than the overall paper. The stamp on the right has a basic fluorescence of MF, but also contains a lot of HF fibres, that stand out very clearly in this picture. 

Unitrade has interchangeably used several names, abbreviations and terms to describe stamps that are essentially the same fluorescence:

  • SF, which stands for speckled fluorescent has been used to describe paper like the above.
  • LF-fl has been used to stand for low fluorescent flecked, which is how the above paper has often been described.
  • F, which stands for fluorescent has also been used to describe the above paper.
So if you find yourself feeling confused when you read Unitrade's listings, it is not without good reason. 

My way of naming this type of paper is as follows, with an example:

DF-fl, Gr, MF, LD for the left stamp and LF-fl, white, HF, S for the right stamp. 

What does all this mean?

On the left stamp:

  • DF-fl stands for dull fluorescent flecked, for the fibres. 
  • Gr. stands for greyish, which is the colour of the paper under UV.
  • MF refers to the fluorescence level of the fibres embedded in the paper,
  • LD stands for low density, which means that the fibres cover the entire surface of the stamp, lightly, such that there is a lot of space between the fibres. 

On the right stamp:

  • LF-fl stands for low fluorescent, flecked, to describe the overall fluorescence, and the fact that there are brighter fibres embedded in the paper. 
  • white, describes the colour of the paper under UV.
  • HF refers to the fluorescence level of the fibres embedded in the paper.
  • S stands for sparse, which means that there is a light sprinkling of these fibres across the surface of the stamp, but the fibres are not at all dense, and there may be areas of the stamp where there are no fibres at all. 

So within this dimension, that of compound fluorescence, there are two sub-dimensions: 

  1. The brightness of the fibres.
  2. The concentration of the fibres.
Unitrade, once again ignores these distinctions, especially the concentration. I would submit that significant differences in the concentrations of these fibres suggest a different papermaking process, and at very least a different composition to the pulp. In my study of this, and other issues, I use the following naming convention to describe the density of the fluorescent fibres in the paper:

  • 1 or 2 - No fibres at all visible, except literally just one of two lone fibres.
  • VVS - very, very sparse - fewer than 10 fibres visible.
  • VS - very sparse a very light sprinkling with no fibres at all on 50-75% of the surface area of the paper.
  • S - sparse - a light sprinkling of individually visible fibres visible on 50-75% of the stamp surface. Large gaps are seen between individual fibres. 
  • LD - low density - a uniform coverage of individually visible fibres across 100% of the stamp surface. 
  • MD - medium density - a uniform coverage of fibres that while idividually visible, are heavily concentrated, and often appear to merge together.
  • HD - high density - almost looks as though it is uniform fluorescence, but on closer examination it is apparent that there is actually an extremely dense concentration of fluorescent fibres that are so close together, you often need a loupe to see them. 
I do not have examples of all seven of these types, as not all of them exist on this issue. Some of these will only be found on later issues of the 1970's. But let me illustrate a few examples now:


The above picture shows four coil pairs for the 8c library coil. Three of these are general tagged: the left pair, and the two pairs on the right. All four of these pairs contain some fluorescent fibres, but in varying amounts and brightness:


  1. The first pair has a very sparse concentration of low fluorescent fibres. The overall paper is a dull fluorescent greyish, so that Unitrade would classify this as LF/fl because of the fibres. My name for this, given the above naming convention would be DF-fl, Gr., LF, VS.
  2. The second pair also has a very sparse concentration of low fluorescent fibres. However, this paper is a dull fluorescent greyish white. Unitrade will likely classify this as "F" paper. My name for this is DF-fl, GW, LF, VS.
  3. The third pair has a sparse concentration of medium fluorescent fibres. The paper is low fluorescent, bluish white. Unitrade will likely classify this as MF. My name for this paper would be LF-fl, BW, MF, S.
  4. The fourth pair has a low density concentration of HF fibres. The paper is a medium fluorescent bluish white. Unitrade will likely classify this as HF, but my name for it is MF-fl, BW, HF, LD. 

Here is a close up shot of the last two papers:



Here you can see that on the left pair there is a light sprinkling of fluorescent fibres across the surface of the stamp, but there are large areas of the stamp that have no fibres, Whereas on the right pair, there is a fairly even distribution of the fibres, right across the surface of the stamp.



Here is a close-up of the first two pairs. As you can see on both, there are still quite a few fibres visible, but they are spread very, very far apart across the entire paper surface. This is what I call very sparse.



Here is another example of sparse on the left and low density on the right. The stamp on the left is the 10c Jack Pine with PVA gum. It is what Unitrade classifies as LF. In reality, the paper is LF-fl, BW, MF, S. The stamp on the right is classified in Unitrade as MF, because it is brighter than the stamp on the left, but in reality is not quite bright enough to be a true MF. Upon closer examination it is really low fluorescent white with a low density concentration of LF fibres, or LF-fl, white, LF, LD, by my naming convention.


Here are two 15c Bylot Island stamps with PVA gum. The stamp on the left is Winnipeg tagged, and is classified in Unitrade as LF. The stamp on the right is general tagged and is also classified by Unitrade as LF. Once again though, they are quite different. The stamp on the left is actually DF-fl, BW, LF, S, while the stamp on the right is LF-fl, BW, LF, LD.


As all of the above examples are stamps with PVA gum, I wanted to show an example of stamps with dextrose gum. The stamp on the left would be classified in Unitrade as dull paper, even though there are a very small number of low fluorescent fibres visible. This stamp would actually be named DF-GW, LF, VS by my naming convention. The middle stamps is what unitrade classifies as the creamy paper LF. In actuality, the paper is indeed a low fluorescent bluish white, but there is also a sparse concentration of MF fibres visible in the paper as well, so that the true name according to my naming convention should be: LF-fl, BW, MF, S. 

More Examples of Confusing Paper Classifications

Hibrite Papers


All the above stamps are listed in Unitrade as hibrite. As you can clearly see, they are not all the same brightness level. In my opinion, only the 6c black block and the 6c coil pair are truly hibrite. The 7c coil pair and the 20c are more of a high fluorescent brightness. 


Dull and Low Fluorescent Papers


Unitrade lists the 6c black CBN die with precancel and general tagging as being on either F, LF or MF paper, while the untagged precancel is listed as LF. The non-precancelled stamps with 4 mm general tagging are listed as being either NF, LF/fl or HF. Clearly, at first glance the first two stamps and the right stamp appear similar, which would suggest LF, even though Unitrade uses LF for two of them and LF/fl for one. The third stamp is clearly what Unitrade classifies as MF.



However, if we take the stamp on the right in the first picture and now lay it on top of the second stamp, we can see that it is clearly DF compared to the second stamp. This is odd, given that the untagged precanceled stamp is only listed as being LF. 



Here is the common, plate 3 PVA gum printing of the 15c that Unitrade classified as F paper. It clearly is no brighter than LF overall and is actually DF-fl, GW, LF, LD.



The stamp on the left is the same, common plate 3 printing while the one on the right is the general tagged version. Unitrade only lists the general tagged version as LF or DF and these two look almost identical. The general tagged version is a little greyer, but is the same in all other respects. 

This concludes my general discussion of paper fluorescence on this issue, and will form the basis for my discussion of fluorescence on the individual values of the series. 

Next week, I will look at the different types of gum used on this issue. 

Tuesday, August 1, 2017

The Papers Used To Print The Centennial Definitives - 1967-1973 - Part One

Overview

Today's post will deal with what is perhaps the most complicated topic of all, as far as this issue is concerned: the paper used to print the stamps. Much attention has been paid to the fluorescence of the paper, which is to say the appearance of the paper when placed under a long-wave ultraviolet lamp. However, there are other attributes of the paper that are important, and worthy of detailed study as well. These include:

1. The thickness of the paper.
2. The whiteness of the paper when viewed in normal light.
3. The direction of the paper weave: i.e. horizontal versus vertical.
4. The texture of the paper on both the front and the back - i.e. smooth versus ribbed.
5. The surface porosity of the paper - porous and soft, versus coated and non-porous.
6. The opacity of the paper.
7. The surface finish - whether or not the paper is matte unsurfaced, or glazed.

This post will discuss all of these attributes in detail as well as covering the topic of paper fluorescence. Keen specialists will notice that the papers used by the Canadian Bank Note Company (CBN) are different from the papers used by the British American Bank Note Company (BABN).

I will start with a general discussion of each attribute, and then I will attempt to illustrate the various paper types, grouped according to printer. Today's post will be the general discussion of the attributes other than fluorescence. Next week I will devote an entire post to the topic of paper fluorescence on this issue. Finally, the following week I will write about each of the specific paper types found on this issue.

Paper Thickness

Most of the papers hover around the same general thickness, which on average, is between 0.003" and 0.0035". However, there are a few stamps that are notably thinner or thicker than this. Significant variations tend to suggest an altogether different paper.

Whiteness Of The Paper in Normal Light

There are notable differences between the appearance of several papers when viewed in normal light, with some of the papers appearing to be a distinct cream, off-white colour, while others are notably white. Usually, but not always, the appearance of the paper will correspond to the fluorescence level, with the cream papers being at the dull end of the scale, and the white papers being at the higher end of the scale. Sometimes though, a paper that appears quite white in normal light, can appear dull or dead under ultraviolet light, and other times there are highbrite papers that do not appear to be overly white in normal light.

These differences are to be found with the papers used by both printers, as we shall see.

The scan below shows an example of the difference I am talking about:



If you look at the above two stamps, you can see very clearly that the paper of the right hand stamp is cream, as opposed to white. The stamp on the left is clearly white - not a very bright white mind you, more of a greyish white, but clearly not cream. The hibrite paper used by the BABN is much brighter than this, appearing very bright white in normal light. 

Direction Of The Paper Weave

The direction of the paper weave is another attribute that shows very clear differences on this set, and this aspect of the paper is often overlooked by collectors, as it is not always obvious. On the stamps that have dextrose gum, where the paper tends to curl from the gum, the direction of the curl gives a clear indication of the weave direction:


  1. If the paper curls from side to side, then the paper is vertical wove.
  2. If the paper curls from top to bottom, then the paper weave is horizontal. 
Where the stamps do not curl, which is all the stamps with PVA gum, the only way to tell for sure which direction the weave of the paper is in is to take the stamp very gently between your thumb and index finger and bend it very gently from side to side, and then from top to bottom. Whichever direction offers the least amount of resistance, i.e. whichever direction is the easiest to bend is the direction of the weave. So stamps on vertical wove paper will bend easily from side to side, while those on horizontal wove paper will bend easiest from top to bottom. 

Often the paper will show a visible mesh that appears to run in either the horizontal or vertical direction. Interestingly, this mesh usually runs in the opposite direction to the actual direction of the weave, so that horizontal wove stamps often have vertical mesh, while those stamps on vertical wove paper have mesh that runs in a horizontal direction. The CBN stamps with PVA gum, which are usually on vertical wove, will usually show a very fine vertical mesh when viewed against a good strong backlight. 

The stamps printed by CBN with dextrose gum are usually printed on vertical wove paper for the low values, i.e. the 1c to 5c plus the CBN printing of the 6c, while the high values are usually found on horizontal wove paper. For the stamps with PVA gum, the direction of the weave is usually vertical, although I have seen some stamps where the paper is clearly horizontal wove.

The determination of weave direction is not always easy. There are some papers with PVA gum where the amount of resistance to bending is almost the same in either direction, and there is no mesh to make the identification easier. In these cases one has to be patient and go with you gut reaction as to which direction offered the least resistance to bending. 

It has been suggested by many philatelists that this is not a significant characteristic because it simply denotes that same paper was fed into the presses in different directions. I would disagree with this for two reasons: for one, as we shall see, there is a very high degree of consistency in the direction for the different denominations and within specific printings, which would not exist if the paper was just fed into the presses in a haphazard fashion. The second reason why I disagree with this position is that the other physical attributes of the paper usually differ. I have yet to come across two papers that are identical in all respects except for the direction of the weave. 

The following scans illustrate the appearance of the different types of mesh that I referred to above:


Both of these stamps are printed on horizontal wove paper. The one on the left is a 10c Jack Pine on dull fluorescent paper, while the one on the right is a 50c Summers Stores on hibrite paper. Both of these stamps have a visible vertical mesh. The mesh on the 50c is much more obvious and can be seen clearly in the scan if you look carefully. The mesh on the 10c is much lighter, and can really only be seen in person - on the scan, the paper just looks smooth.


This scan shows quite nicely the horizontal mesh that is often found on certain papers that were used to print the low values. This one is a 5c blue. The next scan shows a 3c that is printed on a paper that shows no mesh at all:


Note carefully, the difference between the two papers.

Texture Of The Paper - Smooth Versus Ribbed

The vast majority of the stamps of this issue are printed on a paper that is smooth on both the front (printed side) and the back. However, there is a small portion of the stamps printed with PVA gum that are found on a paper that has a distinctly ribbed texture, where the ribbing runs in the horizontal direction. There are also some printings of the booklet stamps by the BABN where the paper appears ribbed in the vertical direction, or is not ribbed, but has a pebbled appearance on the printed surface under magnification. 

The following scans illustrate the standard, smooth paper:


Here you can see no evidence of any ribbing at all - just a smooth surface. The back looks smooth as well:



Here is an example of the 6c CBN printing on vertical wove paper that shows horizontal ribbing on the face:



Here the ribbing is quite distinct, but on some stamps it can be quite hard to see. The easiest way to see it is to tilt the stamp at a 20 degree angle, toward the light, rather than a 45 degree angle. The light will reflect off the surface of the paper in a way that will make the ribbing easy to see.

Here is another example on the 2c green plate 2 block from the lower left position:




Here you can see that the ribbing is even more pronounced than on the 6c above.

The vertical ribbed paper that is often found on the booklet stamps and some of the sheet stamps printed by the BABN is a bit more subtle, but an example taken from the 25c booklet containing the 1c, 3c and 7c is shown below:



The ribbing on this example is hard to see, but if you look at the white background of the label, you can just make it out in places. This is also a good example of a BABN paper that is clearly cream in appearance, rather than white. The ribbing is usually visible under magnification and shows up as a corrugated surface that runs in the vertical direction, whereas this texture does not appear on unribbed stamps, even when such stamps are viewed under high power magnification.



This scan shows another type of paper that is often found on the booklet stamps printed by the BABN. It is characterized by indents in the surface, that give it a pebbly appearance. If you look in the lower margin, you can see several of these indents. They do not occur across the entire surface of the stamp, but rather in a haphazard pattern, so that there will be some parts of the stamp that are smooth. However, there will always be some part of the stamp that will show these indents.

Surface Porosity

The paper of the stamps printed by the CBN on both the high and the low values, generally has a smooth appearance under magnification, but there are usually some very fine spots of unevenness in the paper as well as fine pores visible, such as in the following two stamps:



This stamp is on paper with dextrose gum. As you can see, it has a relatively smooth appearance, but if you look very closely in the upper margin and the other margins, you can see the very fine pores. If you view the stamp at an angle to the light, it will have a surface sheen, but when viewed straight-on, it is clear that the paper has not been coated on the surface, but has merely been smoothed.





This stamp is on paper with PVA gum. The pores are still visible if you look hard enough, but they are not as obvious as on the previous dextrose gum stamp. On most of the high value stamps printed on paper with PVA gum, the surface is very smooth, with only a few very fine pores visible. Other times a very light horizontal ribbing can be seen under magnification, but not at all when the stamps are viewed normally.

Then there are some stamps printed on paper with dextrose gum that had a coating applied to the paper. Usually this coating rendered the stamps completely non-reactive to UV light. However, stamps printed on this paper have a perfectly smooth surface, with few to no pores visble. The following is an example of the 1c printed on this type of paper:


Contrast the appearance of the margins of this stamp with the first 1c stamp shown above. It may take a few long glances for you to see the difference, but once you see it, it is very obvious.

The paper on the BABN stamps is much more porous than that used for the CBN stamps, with the paper appearing to be much softer. The scan below shows an example of the 6c orange, showing the high porosity of the paper:



If you look at the margins around the stamp you can see a lot of pores.


Opacity 

The paper on more or less all of the stamps of this issue is generally opaque in the sense that if you view the stamps from the back you will not be able to see any part of the design through it. If you lay the stamps face-up on a black background, the margins will appear creamy or white, depending on the paper colour, but you will not see any of the black background showing through.

There is one exception though that I discovered by accident when going through a lot of unopened booklets. There was a 25c stapled booklet containing panes of the 1c and 4c, where the panes were printed on oily paper. An example of a 4c stamp from that booklet is shown below:


I had considered the possibility that these were simply panes that had oil spilled on them. However, the staple on the booklet was the right width and showed no sign of any disturbance, and there were no oil stains on the booklet covers, or any of the interleaf pages, which one would expect there to be if oil had been spilled on it. My conclusion is that this is indeed another type of paper that must have been used for a very short run of these.

Surface Finish

As explained above, most stamps are printed on uncoated paper, which has been smoothed into a very fine finish, but there is no shine to either the coated, or the uncoated paper unless the stamps are tilted and viewed at an angle to the light.

However, there was one printing of the 2c and 3c that was made for inclusion in the 25c booklets that were produced for the OPAL manufacturing Co. in Toronto. The paper used for these stamps has a very glossy surface coating that is visible, even when the stamps are not viewed at an angle to the light. It is very distinct, and the colours of both stamps are quite unlike anything that is usually seen on this issue.

An example of the 3c purple from this printing is shown below, along with part of the unprinted gutter that came in the booklet:


This concludes my discussion of the attributes of paper other than fluorescence. Next week's post will discuss paper fluorescence in depth, and then the following week, I will look at the specific paper types found on this issue and describe them in terms of the various attributes that have been discussed here.