Stamp Paper ~ was photo-Litho.

This piece does not explain how to differentiate between
issues of common heritage, but explains the paper makeup
pertinent to each printing method, which may, or may not
assist in ID of that particular printing method.
It has been edited for Australian use, but includes English
particulars as well, however how much use for Indian printings
I could not hazard a guess.

For those who like a little depth to their hobby (Rein comes to mind

Any blatant typos please complain to my OCR programmer.

Acknowledgement :
"The Bookmark Journal" edited, and as explained by Mr. Bernie Doherty
"Australian Stamp News" April 1989

Stamp Paper

I have received a copy of an article on British stamp papers from
Richard Walls of Victoria. Whilst some of the detailed information
on papers used for particular classes of mail is not relevant to the
Australian scene, other details are relevant and I feel of interest. The
following is a summary of the pertinent details from the article in
"The Bookmark" Journal March 1988 edition.
"Paper prepared for printing by photogravure must, have different
qualities from paper intended for lithographic printing. Paper for
photogravure printing needs to be relatively absorbent because of the
high ; speeds employed in the printing, and tne spirit based inks used
in the process. Papers used in both processes are coated, chalk being
used for photogravure printing. The coating provides a smoother
surface than uncoated papers for printing fine screen halftones with
greater fidelity.

Lithographic printing has to take into account the antipathy of oil and
water, the basis for this method. Inks, including phosphor inks, used
in lithographic printing are oil based. The coating used on the paper
for lithographic printing is clay.
To date, four different paper manufacturers have made paper for
British stamps. The first three of these are known to have supplied
paper for Australian stamps. They a

Harrison and Sons Ltd (HS);
Henry and Leigh Slater Ltd (HLS);
Coated Papers Ltd (CPL);
Inveresk Paper Co Ltd (INV). :

With the British stamp paper, a phosphorised coating is
incorporated. This . differs to the material used for Australian , paper.
With the British stamp paper produced by Harrisons, the terms B4
and ACP indicate the different methods of incorporating phosphor
into the coating, rather than a difference between photogravure and
lithographic papers. The term B4 applies to phosphorised paper,
where the phosphor resin was cured on the web. The term ACP is
used to indicate a different method of curing the phosphor resin.
The ACP papers are more sensitive to long wave ultra violet light
than the B4 coatings. As a result, they would have interfered with
the blue (B2) phosphor used by the British Post Office for address
coding on envelopes. To counteract this, an additional amount of
fluorescent brightener is added during manufacture. This "soaks up"
the unwanted long wave response. Under normal conditions, and
long wave irradiation (UV lamp), ACP fluoresces better than the B4
paper.

Some Optical Brightening Agent was added to the paper from 1971,
to make what collectors call Fluorescent Coated Paper. (Perhaps
some of these papers have been used over the last two years on
Australian stamps.)
In regard to gum, Harrisons has used three types: Gum Arabic a
natural exudate, Polyvi-nyl Alcohol and Polyvinyl Alcohol with
Dextrine added, both synthetic. Polyvinyl Alcohol was first seen on
British stamps at the beginning of 1968, its introduction being caused
by a worldwide shortage of Gum Arabic (although Harrisons only
needed 30 tons per year). Australian paper manufacturers had similar
problems at that time with Gum Arabic.

In its pure state, Polyvinyl Alcohol is practically colourless, leading
to early complaints that the stamps were not gummed at all. In
consequence, a small amount of yellowish-brown dye was soon
added to Harrison's Polyvinyl Alcohol. The Polyvinyl Alcohol used
by other manufacturers is pure white, ie no dye is added.
When Polyvinyl Alcohol with Dextrine was introduced, a small
amount of blue-green dye was added. (If you roll a sheet of stamps
into a tube, gummed side inwards, and look through it at a piece of
white paper, the colour is easily seen.)

One sometimes reads about gums fluorescing to varying degrees.
This is extremely doubtful, since none of the gums have fluorescent
substances. It is more likely that it is the base paper under the gum
which varies. Also the dyes used to tint the synthetic gums absorb
UV to some degree, coupled with the amount of dye used from batch
to batch, may cause apparent variations in the fluorescence of the
paper.

To conclude this note on papers, just a word or two about thickness.
Several factors can contribute to the perceived thickness of a finished
stamp, and many of them are variable. Among them a the type of
coating and how it is applied. Coatings consist of pigment in suitable
adhesive binders. They are applied by rolls, brushes, air knives, or by
trailing blades. Blade coatings have become very popular as they are
smoother, and it is possible to apply lower weight coats which are
necessary in some applications. The ink and depth of etching in
photogravure. And even the amount of moisture in the paper.

"Rod" wrote in message
...

This piece does not explain how to differentiate between
issues of common heritage, but explains the paper makeup
pertinent to each printing method, which may, or may not
assist in ID of that particular printing method.
It has been edited for Australian use, but includes English
particulars as well, however how much use for Indian printings
I could not hazard a guess.

For those who like a little depth to their hobby (Rein comes to mind


Any blatant typos please complain to my OCR programmer.

Acknowledgement :
"The Bookmark Journal" edited, and as explained by Mr. Bernie
Doherty
"Australian Stamp News" April 1989

Stamp Paper

I have received a copy of an article on British stamp papers from
Richard Walls of Victoria. Whilst some of the detailed information
on papers used for particular classes of mail is not relevant to the
Australian scene, other details are relevant and I feel of interest.
The
following is a summary of the pertinent details from the article in
"The Bookmark" Journal March 1988 edition.
"Paper prepared for printing by photogravure must, have different
qualities from paper intended for lithographic printing. Paper for
photogravure printing needs to be relatively absorbent because of
the
high ; speeds employed in the printing, and tne spirit based inks
used
in the process. Papers used in both processes are coated, chalk
being
used for photogravure printing. The coating provides a smoother
surface than uncoated papers for printing fine screen halftones with
greater fidelity.

Lithographic printing has to take into account the antipathy of oil
and
water, the basis for this method. Inks, including phosphor inks,
used
in lithographic printing are oil based. The coating used on the
paper
for lithographic printing is clay.
To date, four different paper manufacturers have made paper for
British stamps. The first three of these are known to have supplied
paper for Australian stamps. They a

Harrison and Sons Ltd (HS);
Henry and Leigh Slater Ltd (HLS);
Coated Papers Ltd (CPL);
Inveresk Paper Co Ltd (INV). :

With the British stamp paper, a phosphorised coating
is
incorporated. This . differs to the material used for Australian ,
paper.
With the British stamp paper produced by Harrisons, the terms B4
and ACP indicate the different methods of incorporating phosphor
into the coating, rather than a difference between photogravure and
lithographic papers. The term B4 applies to phosphorised paper,
where the phosphor resin was cured on the web. The term ACP is
used to indicate a different method of curing the phosphor resin.
The ACP papers are more sensitive to long wave ultra violet light
than the B4 coatings. As a result, they would have interfered with
the blue (B2) phosphor used by the British Post Office for address
coding on envelopes. To counteract this, an additional amount of
fluorescent brightener is added during manufacture. This "soaks up"
the unwanted long wave response. Under normal conditions, and
long wave irradiation (UV lamp), ACP fluoresces better than the B4
paper.

Some Optical Brightening Agent was added to the paper from 1971,
to make what collectors call Fluorescent Coated Paper. (Perhaps
some of these papers have been used over the last two years on
Australian stamps.)
In regard to gum, Harrisons has used three types: Gum Arabic a
natural exudate, Polyvi-nyl Alcohol and Polyvinyl Alcohol with
Dextrine added, both synthetic. Polyvinyl Alcohol was first seen on
British stamps at the beginning of 1968, its introduction being
caused
by a worldwide shortage of Gum Arabic (although Harrisons only
needed 30 tons per year). Australian paper manufacturers had similar
problems at that time with Gum Arabic.

In its pure state, Polyvinyl Alcohol is practically colourless,
leading
to early complaints that the stamps were not gummed at all. In
consequence, a small amount of yellowish-brown dye was soon
added to Harrison's Polyvinyl Alcohol. The Polyvinyl Alcohol used
by other manufacturers is pure white, ie no dye is added.
When Polyvinyl Alcohol with Dextrine was introduced, a small
amount of blue-green dye was added. (If you roll a sheet of stamps
into a tube, gummed side inwards, and look through it at a piece of
white paper, the colour is easily seen.)

One sometimes reads about gums fluorescing to varying degrees.
This is extremely doubtful, since none of the gums have fluorescent
substances. It is more likely that it is the base paper under the
gum
which varies. Also the dyes used to tint the synthetic gums absorb
UV to some degree, coupled with the amount of dye used from batch
to batch, may cause apparent variations in the fluorescence of the
paper.

To conclude this note on papers, just a word or two about thickness.
Several factors can contribute to the perceived thickness of a
finished
stamp, and many of them are variable. Among them a the type of
coating and how it is applied. Coatings consist of pigment in
suitable
adhesive binders. They are applied by rolls, brushes, air knives, or
by
trailing blades. Blade coatings have become very popular as they are
smoother, and it is possible to apply lower weight coats which are
necessary in some applications. The ink and depth of etching in
photogravure. And even the amount of moisture in the paper.


This is one of many articles I wrote when I was editor of the Bookmark
Journal; there are several more in just that one issue of the Journal.
The original article, before unauthorised changes were made to it, is:
Machin Papers. The content of this article, and many others in which I
hold the copyright has been incorporated into my Complete Deegam
Machin Handbook, now available on CD. For more information you can
contact me at but add bt before open. The Pipex
address will not work.The MBPC is in the process of converting every
issue of The Bookmark Journal, which was first published in 1971 and
is still going strong, onto a searchable CD which will be made
available to members.

Douglas Myall