Paper and Gum Types on The 1911-1928 Admiral Issue

Paper and Gum Types on The 1911-1928 Admiral Issue

At last, I return to my detailed posts about the popular Admiral series of 1911-1928. This far I have talked about the difference between wet and dry printings, as well as covering all the major shade varieties to be found on each issue.

However, the next major topic that I have only alluded to in my posts about shades, and one that has not received much attention by Unitrade, is the topic of paper and gum. Those who have been collecting this issue long enough and have a keen eye for detail, will eventually notice certain patterns to the characteristics of the paper and gum types that run across the life of this issue. Once you become familiar with these, it will be much easier to distinguish the various printings and shades of the stamps that you have in your collection.

The papers and gum types fall into two distinct groups depending on whether the stamp is a wet printing or a dry printing. For the papers, the main characteristics that I will discuss are the thickness, measured in thousandths of an inch, and the visibility of the mesh of the paper, which can come in three basic types:

  • Coarse - readily obvious when the stamp is viewed face down from the back. 
  • Fine - not obvious unless the stamp is held up to a backlight. 
  • No visible mesh - not visible even when viewed through backlighting. 
In terms of the gum, I will refer to the colour, the sheen of the gum, and its texture. The gum colour on this issue varies from yellow gum on the early printings, to an almost colourless, cream gum on the late dry printings. The sheen of the gum refers to how shiny the gum is. The basic sheens that one encounters on this issue are satin and shiny. Satin gum can be though of as a semi-gloss sheen rather than a shiny gum that reflects a lot of light. The texture refers to how smooth the gum is. On the early wet printings, and the late dry printings, the gum is often streaky, showing distinct, uneven areas, while on others, it is perfectly smooth and even. 
I will attempt to illustrate the differences with scans, 
The Wet Printing Period 1911-1924
The stamps produced during this period can generally be classified into seven groups as follows:
  • 1911-1912 - Coarse or fine vertical (or horizontal) mesh, generally streaky yellow gum.
  • 1912-1913 - Finer vertical (or horizontal) mesh, generally smooth yellow gum.
  • 1914-1917 - Finer vertical mesh, generally a yellowish cream smooth gum. 
  • 1917-1919 - Fine vertical mesh, generally a creamy smooth gum that lacks the yellow of the 1914-1917 period. 
  • 1920-1924 - No visible mesh or no visible mesh and a smooth yellowish cream gum that sometimes has the appearance of being applied with a roller or sponge. 
  • 1923-1924 - No visible mesh and smooth cream satin gum. This is only found on the only wet printing of the $1.
  • 1924 - Very coarse mesh and shiny yellow gum. 
The vast majority of the mint wet printing stamps on the market today are either from the 1920-1922 period, or the 1914-1917 period as is the case with the War Tax stamps. The scarcer shades usually come either from the first two periods, or the 1917-1919 period. It is important to bear this in mind when looking at Unitrade's prices because for example a perf. 8 vertical coil stamp from the early periods before 1915 is considerably scarcer than a more common printing from 1920-1922, but Unitrade does not explicitly deal with this fact. 
As far as paper thickness goes, the stamps generally vary between 0.0035" and 0.0045". The so called thin paper from 1924 on the 2c and 5c is actually 0.0035" usually - no thinner than the normal paper. It only looks this way because of how coarse the mesh is and the fact that the dark colour makes it appear even thinner and more transparent. The thin paper will generally be 0.0025"-0.003", while thick paper must be 0.0045-0.005". 
I will now attempt to show you some of these characteristics.
1911-1912 Coarse or Fine Vertical Mesh and Streaky Yellow Gum
This is the back scan of the 20c grey green from the January 1912 printing. As you can see, the gum is clearly streaky and yellowish, and the vertical mesh is clearly visible. Below is a used example of the 10c first printing on this type of paper:
Here, the mesh is clearly visible, though not a lot more obvious than on the stamp from the 1920-1924 period below. Here is an example of a 1c dull bluish green coil with slightly coarser mesh:
Hopefully you can see that the mesh on this is quite a bit more pronounced than on the other stamps. 
1912-1913 Fine Vertical Mesh and Smooth Yellow Gum
This scan shows the back of a 5c indigo printed during this period. You have to look closely to see the veru fine vertical mesh, but the gum is unmistakably smooth and yellowish.  Below is an example with clearer mesh:
Below is an example of a used stamp from this period:
This looks almost identical to the stamp from the first period, so the difference between the 1911-1912 and 1912-1913 printings really lies in the gum, and even this difference is pretty subtle. 
1914-1917 Finer Vertical Mesh and Yellowish Cream Smooth Gum
This is the back of a 20c olive green War Tax overprinted stamp from 1915. As you can see the mesh is not clearly visible when the stamp is viewed face-down, but it becomes much more obvious when you hold it up to a strong light source. The gum, as you can see is very yellowish compared to the later printings and is perfectly smooth. Here is an example with clearer vertical mesh:
Here the main difference between these and the earlier printings is that the gum is more cream coloured and less yellowish. The mesh, when visible is always fine rather than being coarse, as is often the case with the early printings. 
1917-1919 Fine Vertical Mesh and Smooth Cream Gum
This stamp is a 50c silver black printed in 1917. Note how you cannot see any mesh and the gum is smooth and creamy in colour. The mesh is actually hidden by the gum and it shows up very readily on used stamps and when held up to the light. It is similar to the gum from the 1920-1924 period, except that it is slightly lighter and does not have the appearance of being sponged on on the way that the gum from 1920-1924 tends to. Below is a used example of this same stamp:
Note the very clear vertical mesh pattern in the paper, similar to all the earlier printings. 
1920-1924 Finer Vertical Mesh or No Visible Mesh and Smooth Yellowish Cream Gum
The above is the back of a 7c red brown wet printing, which was issued in 1924. Note the lack of an embossing effect on the back, which is characteristic of wet printing stamps. Also, there is no visible mesh in the paper and the gum is yellowish cream coloured and smooth. Below is a used stamp on this type of paper:
This is the back of a 10c stamp in the common brown purple shade that falls squarely into this period. You can see very clearly the fine mesh pattern in the paper. Below is a used stamp from this period that has no visible mesh:
Generally, the mesh on the paper from this period is less obvious than on the earlier wet printings and on many is not visible at all, whereas on the earlier printings there is always at least a fine mesh visible. 
1923-1924 No Visible Mesh and Smooth Cream Satin Gum
The above is a scan of the back of a $1 red orange from the only wet printing made in 1923. The gum is a very light cream, almost white, with a satin sheen and the paper shows no visible mesh. Below is a scan of the back of a used example:
1924 The So Called Thin Paper - Very Coarse Mesh and Shiny Yellow Gum
Here is the back of a 5c blackish purple on the so called thin paper. You can clearly see very large dark spots on the paper, which are the gaps in the very coarse mesh. The gum is smooth and yellowish. Unfortunately, used stamps on this paper are quite scarce, so I do not currently have one I can illustrate. 
The Dry Printing Period 1922-1928
The stamps produced during this period can generally be divided into three groups:
  • 1922-1926 - Thin paper between 0.0035-0.004", with fine mesh and smooth satin or shiny cream gum.
  • 1924-1926 - Thicker paper between 0.004"-0.0045" with no visible mesh and smooth satin or shiny cream gum. 
  • 1926-1928 - Thicker paper between 0.0045" and 0.0055" with no visible mesh and streaky shiny cream gum.
I will now illustrate these types. 
1922-1926 Thin Paper With Fine Mesh and Smooth Shiny Cream Gum
The mesh is not obvious on this stamp when viewed like this, but it is obvious when held up to the light. The gum as you can see is perfectly smooth and cream coloured. This is the 7c pale red brown on thin paper. Unfortunately I do not have a used example of this paper to show here. 
1924-1926 Thicker Paper With Fine Mesh and Smooth Cream Gum
Above is a back scan of a $1 red orange dry printing from this period. If you look closely at the gum, you can see that the colour is even and the texture smooth. You can just make out dark spots in the paper, which are the gaps between the mesh. 
Below is a used example of a stamp with this type of paper:
You can just make out the fine latticework mesh, though it is very fine. It will become much more obvious when viewed through backlighting. 
1926-1928 Thicker Paper With No Visible Mesh and Streaky Cream Gum
Above is a scan of a brown orange $1 value printed during this period. If you look closely at the scan you can see distinct streakiness in the gum, which shows as alternating light and dark spots on the gum. This gum is generally quite shiny and unfortunately there is no way for me to illustrate that with a 2 dimensional scan. There is also clearly no mesh visible in this paper as viewed from the back. Below is what a used stamp on this paper looks like:
Note the lack of visible mesh. 
In conclusion, although the differences are subtle, it is clear that there are definite differences in the gum used during the life of the issue and that these differences can be used to assign stamps to different periods. The papers are more difficult to classify, as many look very similar, especially on the used stamps. However, if you use a micrometer to properly measure the thickness the task will be easier. Also, the used stamps that show no clear mesh pattern will almost always be from the end of each respective wet or dry period. 
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