KISS-es of paper!

[Rein]

KISS = Keep It Simple Stupid can be applied to everything hoping that even those with the shortest attention span can follow what has been said or written

Let's see!

Paper is made of a mixture of cellulose fibres, fillers and water called pulp. The pulp gets spread egally over a plot in a rectangular frame, whiel shaking the frame, the water drips out through the plot and the fibers stick together forming a coherent layer of what is to be - a sheet of paper. After some time the sheet can be taken off the plot and placed somewhere to dry.

This is hand-made paper described in short!

to be continued .....

[Rein]

Machine-made paper has the same basic ingredients and procedures....

Instead of a relatively small frame, we have a long conveyor belt with an endless plot - the wire. At the begin of the paper machine the pulp will be spread on the belt, at the end of the machine the paper reel [not a loose sheet!] can be separated from the wire. The reel will yet be fed through a set of cylinders to make the paper surface more smooth, lean, etc... Just before the almost dry pulp reaches the end of the machine, it may pass a special cylinder that will imprint the top surface of the reel with certain shapes or characters, etc - the so-called watermark.

The top surface may have a watermark, the bottom surface usually has traces of the plot structure. We can - theoretically - differentiate the two sides of a paper [sheet or reel], the top side named the felt side and the bottom side named the wire side.

to be continued ....

[Rein]

Stamp collectors aren't too interested in theory, they like to see practical matters!

Almost all postage stamps have been printed on machine-made paper - let alone maybe some stamps from the Indian States like Hyderabad in 1856 so that is why we can easily concentrate on the paper machine only....

The ingredients mentioned - fibers, fillers and water - can give remarkable results in our paper!

The fibers can be very finely ground or rather coarse - a thing we can see using a magnifying glass and watch the surface of a stamp - usually the gummed side where a rough surface displays the grooves of longer fibers... At the same time the front of the stamp may be very smooth and no fiber to be seen!

Good quality paper will hardly show any fibers at all - not at the front and not at the back!

to be continued ....

[Rein]

We can add colour dyes to the pulp to make our paper yellowish or bluish... , we can add optical brightening agents to the pulp to make the paper seem more white - whiter than white the washing detergent advertisements wanted us to believe!

We can add coloured fibers to the pulp to make sure that this type of paper is only to be used for security printing. But, in times of economical difficulties certain coloured fibers found their way to the pulp unwantedly

Natural water needs to be used in paper manufacturing, the paper mills usually are located near a river. The water should be crystal clear, but in reality this did not always happen.... The same paper originating from the same paper mill could have a more yellow hue than before or after! Cream paper and white paper - not really different!

The right proportion of fiber grinding and fillers could result in papers with a different feel! Easier to bend or hardly at all....

The thickness of the layer of pulp spread onto the plot determines the eventual thickness of the paper. The paper mill engineers know exactly how to get the right paper weight - 80 grams/square meter or 100 g/m2...

to be continued ....

[Rein]

At the end of the paper machine a set of extra machinery can be placed to have the reel of paper get yet a few additions:

- the coating - an extra layer on top of the paper, usually applied at the felt side of the reel
- the gum - an extra layer on the bottom of the paper, usualy applied at the wire side of the reel

I wrote usually as the inverse situation does happen! And when the visible difference between felt and wire side is good, we can tell it by looking at a coated paper!

Coloured dyes can be added to both coating and gum! Optical brightening agents can be added to the coating, hardly ever to the gum.... All types of luminescent substances - both fluorescent [OBA predominantly] and phosphorescent!

After gumming and coating, the reel of paper can pass sets of cylinders to break the gum or brushing up the coating! Even coatings can show certain structures at times! I called them "glansdiagonalen' or gloss diagonals...

The above applications not necessarily happen immediately after the very paper making. It can be done on separate machines in the same paper mill but also somewhere else in a specialized enterprise ....


to be continued ...

[Rein]

Gumming took place after the printing in the period before 1920 and occasionaly later ... This had to do with the introduction of fast printing presses that were fed by endless reels of paper and thus needed pre-gummed paper. And when the perforation equipment was part of the press, there was no practical way of gumming the loose sheets afterwards...

Recess printing did however for a long time need moistened paper and under those circumstances pre-gummed paper was useless... Only in the 1930-ies dry recess was advanced enough to have pre-gummed paper being used for recess.

Another side-effect of wet recess was the use of line perforations! Comb-perforators could not be used as you always had to count on variable shrinkage of the moistened paper and the fixed sizes in the combs would make large numbers of stamps useless!

to be continued ....

[Rein]

So far, no word about the various types of watermarks!

The pulp on the long belt in the paper machine would - depending on the speed of the machine - have its more or less free floating fibers get orientated in the direction of where the belt was moving - lengthwise!

This orientation can be established rather easily by looking at the always visible fibers - mainly at the wire side.... They turn out to have certain preference! The so-called direction of paper!

Occasionally we need not look for the fibers but we can simply let a piece of paper - our stamps - curl a bit by either moistening and then drying or by heating it up a bit....

The fibers will change their thickness but NOT their length! At least not in the same proportions! The piece of paper will curl forming a cylinder with the axis parallel to the direction of the fibers! This is where the Argentine term "eje de enrollamiento" [coiling axis] comes from!

This is OK for most papers! But do not forget that paper coming from a reel has been wound up long enough to have the tendency to curl with an axis perpendicular to the direction of the fibers.....

And certain papers with either a gum breaking or paper wire structure where the perpendicular direction had been emphasized can give you a completely different idea! In that case we can only rely on the direction of the fibers and should forget about the coiling axis!

to be continued ...

[Rein]

The wire of the conveyor belt leaves an imprint on the wire side of the paper reel. The imprint reflects the fabric of the wire and so when knowing what types of fabric we can have we can tell more about the paper....

Postage stamps paper can be divided in three periods:

1. Before 1938

The fabric of the wire was the most simple one - the so-called linen-binding

2. 1938-1970

The twill binding got introduced.

3. after 1970 the multi-layer bindings were introduced that barely leave any imprint on the surface of the paper and if there still is one it can not be related to neither the linen- nor twill binding.


The linen-binding is the result of horizontal threads passing vertical threads [going over or under them] with the crossing over indicated by an "x":

-x-x-x-x-x-x-x-x
x-x-x-x-x-x-x-x-
-x-x-x-x-x-x-x-x
x-x-x-x-x-x-x-x-
-x-x-x-x-x-x-x-x
x-x-x-x-x-x-x-x-
-x-x-x-x-x-x-x-x
x-x-x-x-x-x-x-x-
-x-x-x-x-x-x-x-x
x-x-x-x-x-x-x-x-

the "x" will be seen by our eyes in "diagonal" lines; the "-" as rhombos!

The twill binding however has the horizontal thread going over 1 vertical thread and then under 2 of them:

-x--x--x--x--x--x
--x--x--x--x--x--
x--x--x--x--x--x-
-x--x--x--x--x--x
--x--x--x--x--x--
x--x--x--x--x--x-
-x--x--x--x--x--x
--x--x--x--x--x--
x--x--x--x--x--x-

Our eyes will still see the diagonal lines but the angle of the lines is different, it is an asymmetrical set of lines, whereas the linen-binding is symmetrical!

to be continued ....

[Rein]

Before 1938 ALL stamps have the linen-binding.

After 1938 we can find the twill binding NOT before 1938! After 1938 we may find the linen-binding still! We can find stamps that exist with both a linen-binding and a twill-binding.

After 1970 linen-binding and twill-binding are hardly found....

I will refer often refer to the linen-binding by "symmetrical paper wire" and to the twill-binding by "asymmetrical paper wire" but only for stamps issued before 1970 as the multi-layer bindings can also be symmetrical or asymmetrical

All notions so far mentioned can be applied to stamps of all countries!

to be continued ....

[Rein]

Linen-binding:



Twill-binding

[Rein]

Now a practical example from the Evita series!





Turning your head you may see the black dots joined!




All lower values [except for the 45c] had been print on paper with a parallel watermark with an asymmetrical paper wire! Several values were later printed on so-called national paper. All values with national paper also had an asymmetrical paper wire but with an orthogonal watermark this time! Only a few values - 10, 20 and 25c - also had been printed on national paper with a symmetrical paper wire!!! They are scarce! The 25c in particular had never been described in Argentine philatelic literature before!

[Otin]

Rein,
Congratulations!!! You have done a stupendous work as I could understand it without any difficulty. It deserves to be translated into Spanish but I am afraid it would be not so easily understood by begginers. My only doubt is why you use the word "plot". In hand made paper for me the wright word would be "mold" but as you continue using it in machinr made paper I get lost. For me plot is a synonime of "conspiration". Congratulations again.
As to the opacity of paper in Eva Perón high values 5 to 50 pesos please see my yesterday reply to Pablo if my memory is right. See Eva Perón threat. Saludos
José

[Otin]

Rein,
Congratulations!!! You have done a stupendous work as I could understand it without any difficulty. It deserves to be translated into Spanish but I am afraid it would be not so easily understood by begginers. My only doubt is why you use the word "plot". In hand made paper for me the wright word would be "mold" but as you continue using it in machinr made paper I get lost. For me plot is a synonime of "conspiration". Congratulations again.
As to the opacity of paper in Eva Perón high values 5 to 50 pesos please see my yesterday reply to Pablo if my memory is right. See Eva Perón threat. Saludos
José

[Rein]

José,

the subject of paper structures [wires, watermarks] is one of the most difficult subjects of philately. I know of well-wrought philatelic Manuals that avoid the subject simply because it was considered too difficult!

The main problem had been the problems of visualizing what the trained eye can see - in either preparing drawing or give verbal descriptions. Fortunately we have strong computer scanners now, which - by using 1200dpi or more - can help us visualizing! That is what Tony Rubiera and I are doing, and I think we should instruct the beginning philatelists how to do the trick!

Linen-bindng:



after connecting the cross-overs by a blue line:



Twill-binding:



after connecting the cross-overs by a blue line:



The purples lines represent diagonals our eyes are less likely to see, but still!

In the linen-binding the diagonals are symmetrical and are equidistant - the next parallel blue line is just as far way in the case of the ascending lines as of the descending lines.

In the twill-binding, however, the ascending blue lines are nearer to each other!

I hope this will make it clear why I refer to the linen-binding as symmetrical and to the twill-binding as asymmetrical. It is not just the angles of the blue lines but also the density!

[PabloS]

Very clear!!!

Saludos. Pablo.