Chalk paper
By chalk paper , philatelists generally refer to any type of coated paper that has been used for the production of postage stamps and postal stationery .
Historical manufacture and definition
Chalk paper was defined as paper that could be written on with metal pens (made of tin and lead) in such a way that it could not be erased with rubber. This is why it used to be called metallic paper . It was produced by either coating very smooth and strong vellum paper with milk of lime and then pressing it, or it was coated with slurried chalk and polished until no more chalk particles came off.
In 1827 the Frankfurt Lorget patented and introduced the manufacture of chalk paper with toxic white lead in France with little success . Later the Parisian lithographer Biard used zinc white . In 1854, Latry began a better practice.
Chalk paper as a determining criterion
Although, in the manufacture of paper chalk as a pigment quite soon due to less sensitive materials such as to generate a closed surface casein or kaolin was replaced has Philatelisten under the term coated paper or gekreidetes paper obtained for the used in the stamp producing coated papers. Since such papers were initially only rarely used or only for parts of a stamp issue due to the higher material costs, the distinction between ordinary paper (rough, porous or machine-smooth paper surface without overlay) and chalk paper is an important criterion for the philatelist when determining and determining the value of Postage stamps. In general, stamps on chalk paper are usually characterized by a higher catalog price, in rare cases the stamps on ordinary paper also have a higher mark. In addition to the type of paper used, the number of copies and the period of use of the respective brands form a further value criterion.
A correct determination of the paper used is also extremely important for handling the postage stamps. Coated papers are more sensitive to high levels of moisture (as occurs when the stamps are peeled off from envelopes and postcards) and to mechanical and chemical influences than stamps printed on ordinary paper. Injuries to the paper surface, e.g. B. by bending or kinking, leave clear and hard to repair marks, especially on coated papers, which then turn out to reduce the value of the brand.
Chalk examiner
A visual inspection based on experience is usually sufficient to determine whether ordinary or chalked paper was used for a postage stamp.
The chalk tester , a silver wire attached to a handle, can hardly be found in the philatelic accessories trade today . That is why philatelists simply use any silver object. If you stroke it over unprinted chalk paper , a gray line will remain at the respective point. This can then be removed with a soft eraser. In order not to damage the stamp, the test is carried out very carefully on the edge of the perforation. If there is a sheet edge, this is used. Philatelists always use this method of paper identification when the visual inspection does not lead to unambiguous results.
Chalk overprint or underprint
To protect against re-use of already used stamps from which the existing cancellation (stamp, pen) has previously been removed by aqueous-chemical processes, individual postal administrations have stamp issues with a mostly strip, line or diamond-shaped pattern made of chalk, casein or kaolin the front of the brand, making it more sensitive to such manipulations. We find such protective measures in Italian stamps from 1863, similar to the issues of the German Empire from 1889 and 1892 and also in Russia 1909–1911.
In the case of chalk printing , this protective layer is applied after the actual stamp printing and stands out only slightly from the previously printed background as a colorless or slightly whitish coating. It is helpful here when determining if you hold the mark at an angle in the incident light. Also in chalk vacuum only partial pigmentation of the paper is made by a sensitive chalk ground is applied before the trademark printing a generally rhombus or lattice-shaped pattern. Both methods are hardly or not at all used today.
literature
- Wolfram Grallert: Lexicon of Philately , 2nd edition, Phil * Creativ GmbH, Schwalmtal 2007, ISBN 3-9321-9838-7 .
Web links
Individual evidence
- ↑ BF Voigt: The complete writing materialist, or the art: to make all kinds of the most excellent nibs, sealing waxes, inks of all colors, wafers and other office materials. 3rd edition 1854, page 187.
- ↑ Technischer Verein zu Carlsruhe : Report on the latest advances in chemical and physical technology. CF Müller I / 1865, page 180.
- ↑ From the editorial office. What is a chalk examiner? In: MICHEL -Rundschau, issue 4/2006, p. 26.