Paper Textures:
1. Horizontal wove paper showing strong ribbing on both the front and back of the stamps.
2. Horizontal ribbed paper showing ribbing on the front only.
3. Horizontal ribbed paper showing ribbing only on the back.
4. Horizontal wove paper showing no ribbing at all either on the front, or the back - the horizontal mesh only being visible when the stamps are held up to a strong light source.
5. Vertical wove paper showing no visible ribbing.
6. Vertical wove paper showing distinct vertical ribbing on front and back.
It was suggested in one philatelic article (I can't remember where) that the vertical and horizontal papers were the same and only reflect the fact that the printing plates were rotated in late 1958 from a horizontal orientation to a vertical one. However, close examination reveals that this is not the case. The appearance of the ribbing and the appearance of the mesh is completely different with these papers. Also most of the horizontal wove papers are between 0.0035-0.004" thick, whereas the vertical wove papers are usually exactly 0.0035".
Whether all six textures should be represented in a collection is a matter of personal preference. I can see how some collectors may feel that papers 1-3 and 5-6 are the same and that distinguishing between them is overkill. However, I believe that based on their characteristics, at a minimum a collection should feature three of these types.
The scans below show the three basic types:
The above is am example of the horizontal wove with the clear ribbing. You can see the ribbing at the top of the block in the top selvage. One very good way to reliably detect the ribbing is to look at the stamps at an oblique angle to the light. Then it will be clearly visible. The horizontal ribbed papers predominated until about 1956-1957, when the type with smooth surface appeared.
This paper is horizontal wove and shows ribbing on the back, but is completely smooth on the front, even when viewed at an angle to the light. It usually appears on plates from about 9 onwards and predominates until the vertical wove papers appear.
This is the vertical wove paper that shows no distinct ribbing. It is often whiter in appearance than the horizontal wove paper.
Reactions Under UV Light:
1. Non-fluorescent violet reaction - usually found on the smooth horizontal wove.
2. Dull fluorescent light violet reaction
3. Dull fluorescent greyish reaction
4. Dull fluorescent greyish white reaction
5. Dull fluorescent white reaction
6. Dull fluorescent violet white reaction
7. Dull fluorescent bluish white reaction
8. Dull fluorescent ivory reaction
Types 2 through 8 are found on all the paper types, though some are clearly less common than others. Ivory, bluish white, violet white and light violet appear, based on the blocks I have examined so far to be much less common than the other types. Again, whether or not all eight should be included in a collection is a matter of personal preference. Many collectors may see little difference between types 1-2, 3-5 and 6-7. However, I believe that most would, if they could see them all together, would recognize at least four types.
Understanding the differences between these papers and the gums will prove to be invaluable in sorting the printings of the high values, which are otherwise very difficult to tell apart, as most show very little variation in shade and nearly all were printed on dull fluorescent papers.