Today, I start examining the printings of one of the more complicated low value denominations in the series: the 4 cent carmine, which depicted a lock in the St. Lawrence Seaway, in Quebec. In addition to sheet stamps and coils, this stamp was also issued in three different booklets, as well as in the cello-paq miniature panes of 25, that sold for $1 each. The sheet stamps came with two different basic types of Winnipeg tagging, as well as general Ottawa tagging. It is a complex stamp, and three separate posts will be needed to deal with all the complexity. Today's post will be the first of these, and will examine all of the untagged sheet stamps.
Unitrade lists four varieties of paper for the stamps with dextrose gum, that were issued between February 8, 1967 and May 1972, when the stamps with PVA gum appeared. Two paper varieties are listed for the precancelled stamps as well. Only a single listing is given to the PVA gum untagged stamps, though as we shall see, there are several collectible varieties. This is one of those stamps in the series, where the inks are affected by ultra-violet light. So in addition to shade varieties and paper varieties, there are also differences in shade under UV light to consider.
Three plates were used to print this value. All three plates are found with dextrose gum but the only plate 3 is found on the PVA gum stamps. The selvage of these blocks is narrower than the plate 3 blocks with dex gum, making them easy to spot.
The remainder of this post will look at these stamps in detail.
The Stamps With Dextrose Gum - Unitrade 457, 457i, 457ii, 457iii, 457xx and 457xxi
Paper Characteristics Other Than Fluorescence
As with the other low value stamps of this series, that were printed by CBN, and issued with dextrose gum, the paper used on all the stamps and blocks that I have examined, is always vertical wove, so that the mint stamps and blocks always curl from side to side. However, I have found that there are three different types of paper on these printings, ignoring fluorescence:
Paper Fluorescence
Non-Fluorescent Papers
There are several types of paper that all meet the definition of non-fluorescent, for the purposes of Unitrade's listings. The colours of the paper under UV light vary from violet, to brownish grey and finally to grey. It can take some experience to properly distinguish the non-fluorescent and dull papers. I have tried taking comparative pictures of the two paper types, but unfortunately the difference does not show up very clearly in the pictures taken with my camera. The basic difference between dull fluorescent and non-fluorescent is that the non-fluorescent papers are all darker in colour, appearing deep violet, brown and grey, especially when compared to any of the dull fluorescent papers, which always appear whitish by comparison. You may have to sort a quantity of singles and blocks to really become comfortable with the difference, but you should find that it becomes quite clear after a while.
The first picture below shows two examples of the non-fluorescent brownish grey paper:
These two blocks appear more or less the same under the UV light, with the ink of the block on the left actually appearing to be a little darker than the one on the right. Oddly enough though, the camera makes the difference look much more stark, and shows the plate 1 block being a brighter colour than the plate 3! However, this is not at all how it appears under the UV light in reality, which is strange.
The next picture shows a block on a non-fluorescent paper that gives a violet reaction under UV light:
You can hopefully see the violet colour clearly on the above block. Note how the camera is distorting the colour of the stamps on the left side of the block, as compared to the right.
Next, we have two examples of the greyish non-fluorescent paper. One block is grey with a violet undertone and the other is a plain grey:
The violet grey paper is the plate 1 block on the right, while the plain grey is the plate 2 block on the left. The ink colour of the plate 2 block appears to be slightly brighter than the plate 1 block. This is consistent with how these actually appear under the ultraviolet light.
Dull Fluorescent Papers
The dull fluorescent papers found on this stamp vary from deep ivory and brownish greys, through to grey and finally light grey.
An example of the basic dull fluorescent paper, giving a grey reaction is shown below:
The next picture shows two examples of dull fluorescent paper giving a light grey reaction under UV light, with one block being completely free of fluorescent fibres, and the other one having very few low fluorescent fibres embedded in the paper. Both examples come from plate 3:
The next picture shows two examples of a dull fluorescent paper, giving a deep ivory grey reaction under UV light. These two blocks both have the exact same appearance in normal light, but appear very different colours under UV light:
The block on the right appears a deep carmine under, UV, while the block on the right appears a bright scarlet red.
The next picture shows two examples of the dull fluorescent paper that give a yellowish to brownish grey reaction under UV. Both are different shades in normal light, and also under the UV light:
Low and Medium Fluorescent
The next picture shows examples of the two papers that Unitrade lists as low fluorescent and medium fluorescent:
The so called low fluorescent paper is shown on the left, while the medium fluorescent is shown on the right. In reality, both are dull fluorescent papers that are made to appear brighter, due to the inclusion of fluorescent fibres, that vary in brightness, from low to high, and in concentration. The low fluorescent block contains a very sparse concentration of low fluorescent fibres, and a few high fluorescent ones, which make it appear LF overall. The block on the right contains very sparse concentrations of low, medium and high fluorescent fibres. Together, these make the paper appear MF overall.
Also, this picture shows another example of how two colours that are slightly different in normal light, also appear different under UV light. If you look at the bottom two stamps towards the centre, you can see that the ink of the stamps on the right is a very deep carmine, which contains some black, whereas the ink of the stamp on the left is brighter, and lacks the black undertone.
Shades
Despite the fact that Unitrade does not list any shades for this stamp, there are a large range of shades that range from subtle, to really quite obvious. The scans below show the shade variations that I have found on this stamp:
The block on the left is printed in a shade that is closest to carmine-red on the Gibbons colour key, but is brighter. The block on the right is closest in shade to rosine on the Gibbons key, but again, the actual shade is deeper that what the Gibbons colour swatch shows.
Let's look at two more shades:
These two shades are similar to the last two, but are slightly different. The block on the left is another variant of bright carmine red, but this one is lighter than the bright carmine red shown in the last scan. The block on the right is a perfect match to Gibbons's rosine shade.
Now for two more:
The block on the left is another variation of rosine. This time it is a bit brighter than the pure rosine that is shown in the second scan above. The block on the right is a perfect match to Gibbons's carmine-red.
Now, let's look at two more shades:
The block on the left is a dull carmine-red, while the block on the right is a pale bright carmine-red.
Now, let's take a look at the last shade variety that I have found on the dex gum stamps: the pale dull carmine-red:
This shade is similar to the pale, bright carmine red, but is definitely duller.
This makes a total of nine different, identifiable shades of the what Unitrade calls "carmine". Some of the differences are quite subtle, so the number of shades you include in your collection, must be a matter of personal preference.
In addition to differences in the appearance of the colours in normal light, the ink colours can appear quite different under UV light. Generally, in all cases, they still appear at least a very deep carmine, which is still a shade of red. Therefore, I consider the inks used on all printings of the dextrose gum stamps to be non-transformative. Throughout this post you will see pictures taken with my phone camera of the stamps under UV light. In many of these pictures, you will see clear differences in the appearance of the inks. Sometimes, these differences are the camera or lighting conditions playing tricks on our eyes, but in many instances, they are true representations of these differences. In most instances, these differences are merely more obvious representations of different shades, which are already distinguishable from one another in normal light. However, in some cases, the same shades in normal light will appear different under UV light. Some of the differences I have found on the shades identified here include:
Gum
Three different types of dextrose gum are found on these stamps. These gums differ in terms of colour, uniformity of application, and the surface sheen:
Perforations
Like the other line perforated low values of this series, there are four different line perforations that can be found: 11.85, 11.95, 11.85 x 11.95 and 11.95 x 11.85.
Precancels
Unitrade lists the precancelled stamp as existing on both dull fluorescent and low fluorescent paper. However, I have also found that it exists on non-fluorescent paper as well.
The picture below shows an overall comparison of the three paper types:
Now, let's look at close up pictures showing examples of each paper type individually.
The picture below shows three examples of the precancel, each printed on a slightly different dull fluorescent paper:
The block is printed on paper giving a deep ivory reaction under UV, while the upper right stamp is on paper giving a violet grey reaction, and the lower right stamp is on paper giving a grey reaction under UV light.
The colours under UV light appear slightly different than the picture above makes them appear. The upper right stamp appears deep carmine, just as it appears in the picture. The block appears a deep bright carmine under UV, which is similar to what is shown in the picture, but deeper. The lower right stamp is printed in a deep scarlet red ink, that looks brighter than either the block, or the upper right stamp, even though it appears darker, in the picture than the block.
The next picture shows two examples of the precancel on non-fluorescent paper:
The block is printed on paper that gives a brownish grey reaction under UV light, while the single stamp is on paper that appears violet under UV.
This is an example of the precancel on the so-called low fluorescent paper. This paper is dull fluorescent greyish paper that contains a very sparse concentration of low fluorescent fibres and medium fluorescent fibres, as well as very few high fluorescent fibres. Together, these fibres make the paper appear low fluorescent overall.
Bringing it All Together
This is by far, the most potentially complex of the low values with dextrose gum that I have studied so far:
The PVA Gum Stamps - Unitrade 457iv.
Paper Characteristics Other Than Fluorescence
Like the stamps printed with dextrose gum, the PVA gum stamps are printed using vertical wove paper. There are two different basic paper types, in terms of the characteristics other than fluorescence. However, each of these seems to correspond to a specific paper fluorescence level, so that there are still only as many paper types as there are fluorescence levels. However, it is still good to be aware of the differences:
Paper Fluorescence
Unitrade only lists a single, low fluorescent paper for this stamp. However, as the pictures below show, I have found at least three varieties of paper, one of which is actually quite dull, being much closer to dull fluorescent, even though it is still considered to be low fluorescent.
The first picture below shows the three paper types I have found:
At the upper left, we have the low fluorescent paper, containing fluorescent fibres. On the upper right, is another variety of paper that is dull fluorescent and contains a sparse concentration of fluorescent fibres, and finally on the bottom, we have a dull fluorescent bluish white paper, with a very sparse concentration of low fluorescent fibres embedded in the paper.
In studying these stamps, I have found that nearly all of the stamps I have examined with PVA gum are found on the first type of paper. The second type is much, much scarcer, while the third type is the scarcest on the untagged stamps. As we shall see in next week's post, the duller papers were primarily used for the Winnipeg tagged stamps with PVA gum.
Once again, this picture shows the camera playing a visual trick on the viewer: the bottom block appears to be printed in an ink giving a much brighter reaction under UV light than the other two blocks. In reality, the top left block is printed in an ink that appears brighter carmine under UV, while the other two blocks are printed in ink that appears to be deep carmine under UV light. Again, this is the opposite to how the inks appear in the above picture.
Now let's take a look at some pictures of the backs of these blocks to get a better idea of the differences between these three papers:
As you can see, the overall concentration of fluorescent fibres in this paper is a low density concentration (i.e a light, even sprinkling across the entire stamp surface). The fluorescent fibres are of different brightness levels, and closer examination reveals that the fibres are low, medium and high fluorescent, and it is very sparse concentrations of each of these types of fibres, that is coming together to form an overall low density concentration of fibres, that makes this paper appear low fluorescent overall. If you look closely with a loupe, you can see that the basic fluorescence level of this paper is dull fluorescent bluish grey.
The block on the left is the dull fluorescent paper. The paper colour under UV is a dull fluorescent bluish white, and the paper does contain a very sparse concentration of low fluorescent fibres. However, these are not noticeable unless you look very closely at the block under UV light. The overall brightness level in my opinion, is still low fluorescent, especially when you compare it to the dull fluorescent papers of the dextrose gum printings.
The block on the right is the second type of paper: the dull fluorescent violet-grey paper with the sparse concentrations of low and medium fluorescent fibres, and the very few high fluorescent fibres.
The block on the left appears a brighter white here in the picture, mainly because it is being compared to the violet grey of the second block on the right. However, the glow of the paper is not bright enough for it to be considered low fluorescent
The picture below shows the back of the block on the dull fluorescent paper:
Note how there are very few low fluorescent fibres visible in the paper of this block as compared to the other papers. From what I have seen so far in studying this stamp, this duller paper is much scarcer than the other low fluorescent papers.
Shades
There is a narrower range of shades on these stamps, as compared to the stamps with dextrose gum. However, there are still at least two shades, as shown below:
The block on the left is closest to Gibbons's rosine shade, but the colour here is deeper. The block on the right is a bright shade of rosine.
Under UV light, the colours vary in appearance as well. Again, all of the inks still appear to be shades of either carmine, or carmine-red. So I would classify the inks used to print these as non-transformative as well. The bright rosine shade appears carmine-red under UV, but the deeper rosine shade can appear either carmine-red or carmine.
So, when the appearance under UV is considered, there are really 3 different shades on the PVA gum printings. I would assume that with enough patience, it is probably possible to find all three shades on all three paper types.
The pictures below show how the shades of these stamps vary under UV light:
These two blocks are printed on the low fluorescent paper containing the overall low density of fluorescent fibres. In normal light, the shade of both blocks is the deeper rosine. However, under UV light, the smaller block appears to be printed in a carmine-red ink, while the larger block appears carmine.
Gum
The PVA gum used to print these stamps, exists in two very similar types. Both are white in colour, and are smooth. The main difference between the two lies in the thickness and the surface sheen:
Perforations
Consistent with all the other PVA gum stamps I have examined so far, all of the stamps I examined were line perforated 11.85 only. This is consistent with my observation that the 11.95 machines had been fully retired by 1972 when these stamps were issued.
Bringing it All Together
This is much less complicated as compared to the stamp with dextrose gum. Nevertheless, there is more scope to it than Unitrade might lead you to think. Based on the above, there could be up to: 3 x 3 x 2 = 18 collectible varieties for single stamps. Only one plate, plate 3 was associated with this printing, which means that there could be up to 72 plate blocks and 216 blank corner blocks that could be collected for these printings.
This concludes my discussion of the printings of the 4c untagged centennial sheet stamps. Next week, I will discuss the printings of the tagged sheet stamps.
Unitrade lists four varieties of paper for the stamps with dextrose gum, that were issued between February 8, 1967 and May 1972, when the stamps with PVA gum appeared. Two paper varieties are listed for the precancelled stamps as well. Only a single listing is given to the PVA gum untagged stamps, though as we shall see, there are several collectible varieties. This is one of those stamps in the series, where the inks are affected by ultra-violet light. So in addition to shade varieties and paper varieties, there are also differences in shade under UV light to consider.
Three plates were used to print this value. All three plates are found with dextrose gum but the only plate 3 is found on the PVA gum stamps. The selvage of these blocks is narrower than the plate 3 blocks with dex gum, making them easy to spot.
The remainder of this post will look at these stamps in detail.
The Stamps With Dextrose Gum - Unitrade 457, 457i, 457ii, 457iii, 457xx and 457xxi
Paper Characteristics Other Than Fluorescence
As with the other low value stamps of this series, that were printed by CBN, and issued with dextrose gum, the paper used on all the stamps and blocks that I have examined, is always vertical wove, so that the mint stamps and blocks always curl from side to side. However, I have found that there are three different types of paper on these printings, ignoring fluorescence:
- A cream paper that has a very smooth printing surface. Under magnification, the paper appears to be lightly coated, as there are no loose or stray paper fibres. When held up to a strong back-light, the paper mesh appears to run in both directions. There is no ribbing visible on either the front, or the back of this paper.
- A deep cream coloured paper that also has a very smooth printing surface, similar to the first type above. When held up to a strong back-light, there is a clear horizontal mesh visible. In addition, very light horizontal ribbing is visible on the gummed side of the paper, when it is viewed from an angle.
- A cream paper that has a smooth, but uncoated printing surface, as evidenced by its porous appearance under 10x magnification. When held up to a strong back-light, there is a very distinct horizontal mesh visible, and distinct horizontal ribbing is visible on the gummed side of stamps and blocks printed on this type of paper.
Paper Fluorescence
Non-Fluorescent Papers
There are several types of paper that all meet the definition of non-fluorescent, for the purposes of Unitrade's listings. The colours of the paper under UV light vary from violet, to brownish grey and finally to grey. It can take some experience to properly distinguish the non-fluorescent and dull papers. I have tried taking comparative pictures of the two paper types, but unfortunately the difference does not show up very clearly in the pictures taken with my camera. The basic difference between dull fluorescent and non-fluorescent is that the non-fluorescent papers are all darker in colour, appearing deep violet, brown and grey, especially when compared to any of the dull fluorescent papers, which always appear whitish by comparison. You may have to sort a quantity of singles and blocks to really become comfortable with the difference, but you should find that it becomes quite clear after a while.
The first picture below shows two examples of the non-fluorescent brownish grey paper:
The next picture shows a block on a non-fluorescent paper that gives a violet reaction under UV light:
Next, we have two examples of the greyish non-fluorescent paper. One block is grey with a violet undertone and the other is a plain grey:
Dull Fluorescent Papers
The dull fluorescent papers found on this stamp vary from deep ivory and brownish greys, through to grey and finally light grey.
An example of the basic dull fluorescent paper, giving a grey reaction is shown below:
The next picture shows two examples of dull fluorescent paper giving a light grey reaction under UV light, with one block being completely free of fluorescent fibres, and the other one having very few low fluorescent fibres embedded in the paper. Both examples come from plate 3:
The block on the right is the one with the fluorescent fibres. They are hard to see, but you can just make one out in the selvage, above the word "limited". Again, these two blocks show quite a marked difference in the appearance of the ink under UV. However, the difference in reality is not quite as drastic as the picture makes is appear.
The next picture shows two examples of a dull fluorescent paper, giving a deep ivory grey reaction under UV light. These two blocks both have the exact same appearance in normal light, but appear very different colours under UV light:
The next picture shows two examples of the dull fluorescent paper that give a yellowish to brownish grey reaction under UV. Both are different shades in normal light, and also under the UV light:
The difference between the shades are quite stark under the UV light, with the right block being a very deep carmine shade, while the left block is a very bright scarlet red colour under UV. The paper of the right block is a light brownish cream colour in normal light, and brownish grey under UV. The paper of the left block is a lighter colour in normal light, and a slightly lighter grey under UV light.
Low and Medium Fluorescent
The next picture shows examples of the two papers that Unitrade lists as low fluorescent and medium fluorescent:
Also, this picture shows another example of how two colours that are slightly different in normal light, also appear different under UV light. If you look at the bottom two stamps towards the centre, you can see that the ink of the stamps on the right is a very deep carmine, which contains some black, whereas the ink of the stamp on the left is brighter, and lacks the black undertone.
Shades
Despite the fact that Unitrade does not list any shades for this stamp, there are a large range of shades that range from subtle, to really quite obvious. The scans below show the shade variations that I have found on this stamp:
Let's look at two more shades:
Now for two more:
Now, let's look at two more shades:
Now, let's take a look at the last shade variety that I have found on the dex gum stamps: the pale dull carmine-red:
This makes a total of nine different, identifiable shades of the what Unitrade calls "carmine". Some of the differences are quite subtle, so the number of shades you include in your collection, must be a matter of personal preference.
In addition to differences in the appearance of the colours in normal light, the ink colours can appear quite different under UV light. Generally, in all cases, they still appear at least a very deep carmine, which is still a shade of red. Therefore, I consider the inks used on all printings of the dextrose gum stamps to be non-transformative. Throughout this post you will see pictures taken with my phone camera of the stamps under UV light. In many of these pictures, you will see clear differences in the appearance of the inks. Sometimes, these differences are the camera or lighting conditions playing tricks on our eyes, but in many instances, they are true representations of these differences. In most instances, these differences are merely more obvious representations of different shades, which are already distinguishable from one another in normal light. However, in some cases, the same shades in normal light will appear different under UV light. Some of the differences I have found on the shades identified here include:
- On the light bright carmine red shade: deep carmine, deep bright carmine-red, carmine-red.
- On the rosine shade: carmine and carmine-red.
- On the deep rosine shade: carmine and carmine-red.
So, in addition to the 9 different shades that are visible in normal light, it is possible to add four more variations that can only be seen under ultraviolet light, for a total of 13 different shades.
Gum
Three different types of dextrose gum are found on these stamps. These gums differ in terms of colour, uniformity of application, and the surface sheen:
- A streaky, yellowish cream gum that has a semi-gloss sheen.
- A smooth, yellowish cream gum that has a semi-gloss sheen.
- A smooth, yellowish cream gum that has a very glossy sheen.
I have not yet found examples of either the blotchy gum that was found on some printings of the 1c and 3c, nor have I found any examples of the thinner gum with the satin sheen, that I have also found on these other low values, which is interesting.
Perforations
Like the other line perforated low values of this series, there are four different line perforations that can be found: 11.85, 11.95, 11.85 x 11.95 and 11.95 x 11.85.
Precancels
Unitrade lists the precancelled stamp as existing on both dull fluorescent and low fluorescent paper. However, I have also found that it exists on non-fluorescent paper as well.
The picture below shows an overall comparison of the three paper types:
The non-fluorescent paper is shown on the left. The middle stamp is on dull fluorescent paper. Finally, the right stamp is the low fluorescent paper.
Now, let's look at close up pictures showing examples of each paper type individually.
The picture below shows three examples of the precancel, each printed on a slightly different dull fluorescent paper:
The block is printed on paper giving a deep ivory reaction under UV, while the upper right stamp is on paper giving a violet grey reaction, and the lower right stamp is on paper giving a grey reaction under UV light.
The colours under UV light appear slightly different than the picture above makes them appear. The upper right stamp appears deep carmine, just as it appears in the picture. The block appears a deep bright carmine under UV, which is similar to what is shown in the picture, but deeper. The lower right stamp is printed in a deep scarlet red ink, that looks brighter than either the block, or the upper right stamp, even though it appears darker, in the picture than the block.
The next picture shows two examples of the precancel on non-fluorescent paper:
Bringing it All Together
This is by far, the most potentially complex of the low values with dextrose gum that I have studied so far:
- Three different types of paper, ignoring fluorescence.
- 13 different types of non-fluorescent, dull fluorescent, low fluorescent and medium fluorescent paper.
- 13 different inks.
- 3 different gum types.
- 4 different perforations.
- both precanceled and non-precanceled stamps.
It is not clear whether or not every potential paper variety can be found with every level of fluorescence, every type of gum etc. But if this is possible, then the number of collectible varieties is enormous:
3 x 13 x 13 x 3 x 4 x 2 = 12,168 varieties!
There were 3 plates used to print these stamps too, so if every possible variety exists in a plate block, there would be 36,504 collectible varieties of each plate block, 146,016 collectible plate blocks when considering all four corners. Finally, if blank corner blocks are collected, then there could be an additional 146,016 possible blank corner blocks that one could collect.
The PVA Gum Stamps - Unitrade 457iv.
Paper Characteristics Other Than Fluorescence
Like the stamps printed with dextrose gum, the PVA gum stamps are printed using vertical wove paper. There are two different basic paper types, in terms of the characteristics other than fluorescence. However, each of these seems to correspond to a specific paper fluorescence level, so that there are still only as many paper types as there are fluorescence levels. However, it is still good to be aware of the differences:
- A very white paper, that appears white, even when viewed against a stark white background. Under magnification the printed surface is lightly coated, as evidenced by the fact that there are no loose or stray paper fibres on the surface. When viewed against strong back-lighting, there is no clear mesh pattern. These characteristics correspond to the papers containing less fluorescent fibres that are the scarcer types.
- A white paper that appears very light off-white when viewed against a stark white background. Under magnification, the printed surface is lightly coated, as evidenced by the fact that there are no loose or stray paper fibres on the surface. When viewed against strong back-lighting, there are closely spaced vertical striations visible in the paper. You can also see them on the gum side if you hold the paper at an angle to the light and move it back and forth. These characteristics correspond to the more common low fluorescent paper that contains the largest concentration of fluorescent fibres, that will be described below.
Paper Fluorescence
Unitrade only lists a single, low fluorescent paper for this stamp. However, as the pictures below show, I have found at least three varieties of paper, one of which is actually quite dull, being much closer to dull fluorescent, even though it is still considered to be low fluorescent.
The first picture below shows the three paper types I have found:
In studying these stamps, I have found that nearly all of the stamps I have examined with PVA gum are found on the first type of paper. The second type is much, much scarcer, while the third type is the scarcest on the untagged stamps. As we shall see in next week's post, the duller papers were primarily used for the Winnipeg tagged stamps with PVA gum.
Once again, this picture shows the camera playing a visual trick on the viewer: the bottom block appears to be printed in an ink giving a much brighter reaction under UV light than the other two blocks. In reality, the top left block is printed in an ink that appears brighter carmine under UV, while the other two blocks are printed in ink that appears to be deep carmine under UV light. Again, this is the opposite to how the inks appear in the above picture.
Now let's take a look at some pictures of the backs of these blocks to get a better idea of the differences between these three papers:
Here you can see that this paper contains many fewer fluorescent fibres than the paper containing the very sparse concentrations of low, medium and high fluorescent fibres. This paper contains very sparse concentrations of low, and medium fluorescent fibres, as well as very few high fluorescent fibres. The basic fluorescence level of this paper, ignoring the fluorescent fibres, is dull fluorescent violet grey, with a sparse concentration of brownish woodpulp fibres in the paper.
This gives us a good idea of the difference between the first two types of paper. Now, to see the difference between the third type and the second type of paper, let's take a look at the comparison below:
The block on the right is the second type of paper: the dull fluorescent violet-grey paper with the sparse concentrations of low and medium fluorescent fibres, and the very few high fluorescent fibres.
The block on the left appears a brighter white here in the picture, mainly because it is being compared to the violet grey of the second block on the right. However, the glow of the paper is not bright enough for it to be considered low fluorescent
The picture below shows the back of the block on the dull fluorescent paper:
Shades
There is a narrower range of shades on these stamps, as compared to the stamps with dextrose gum. However, there are still at least two shades, as shown below:
Under UV light, the colours vary in appearance as well. Again, all of the inks still appear to be shades of either carmine, or carmine-red. So I would classify the inks used to print these as non-transformative as well. The bright rosine shade appears carmine-red under UV, but the deeper rosine shade can appear either carmine-red or carmine.
So, when the appearance under UV is considered, there are really 3 different shades on the PVA gum printings. I would assume that with enough patience, it is probably possible to find all three shades on all three paper types.
The pictures below show how the shades of these stamps vary under UV light:
Gum
The PVA gum used to print these stamps, exists in two very similar types. Both are white in colour, and are smooth. The main difference between the two lies in the thickness and the surface sheen:
- One type is thicker and has a shiner finish, being a satin sheen.
- One type is thinner, with a much duller finish, being an eggshell sheen.
The thinner gum seems to be associated with the scarcer, less fluorescent papers, while the thicker shiner gum is associated with the later printings, though it is possible that it could exist with both papers and all shade combinations. A proper study would have to be conducted in order to settle this definitively.
Perforations
Consistent with all the other PVA gum stamps I have examined so far, all of the stamps I examined were line perforated 11.85 only. This is consistent with my observation that the 11.95 machines had been fully retired by 1972 when these stamps were issued.
Bringing it All Together
This is much less complicated as compared to the stamp with dextrose gum. Nevertheless, there is more scope to it than Unitrade might lead you to think. Based on the above, there could be up to: 3 x 3 x 2 = 18 collectible varieties for single stamps. Only one plate, plate 3 was associated with this printing, which means that there could be up to 72 plate blocks and 216 blank corner blocks that could be collected for these printings.
This concludes my discussion of the printings of the 4c untagged centennial sheet stamps. Next week, I will discuss the printings of the tagged sheet stamps.