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.
- 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.
- 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.