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Edo G. Loeber: Criteria Affecting the Identity of Watermarks

Our starting-point is the manufacture of hand-made paper, moulded sheet after sheet, couched, pressed, dried, possibly sized and glazed, and maybe printed.
In this connection the following principle is basic: no action ever repeats itself under exactly identical conditions. This implies that theoretically the result differs from one case to the next. These differences may be minimal, but we cannot ignore them. Let us examine the causes of these differences between sheets of hand-made paper coming from one and the same mould (not from a pair of moulds).

A. The stuff

  1. After each dipping the fibre content in the vat not only diminishes, but
  2. the proportion of long and short fibres changes, leaving more short than long fibres.
  3. Adding stuff to the vat alters the fibre content and the proportion of long and short fibres once again.
  4. The fibre content therefore changes constantly during the moulding of a whole post; in the end this results in a predominance of short fibres. R6my Green (Maidstone) questions this. In his opinion it could be true for Richard de Bas (Ambert), but unlikely to be perceptible – even under a microscope – at a mill like Hayle MW, with constant addition of stuff.
  5. With each moulding the fibres settle themselves differently along the laid, chain, and profile wires, on account of the shaking of the mould and the closing of the sheet, whereas
  6. in each sheet of paper the proportion of the fibres lying in the length and in the breadth show slight varieties, the more so with semi-skilled vatmen.
  7. When the composition of the stuff (linen, hemp, or cotton) is altered, considerable differences in lookthrough occur, just as later in the shrinking of the paper when dried.
  8. The degree of retting and beating also has its influence. This becomes apparent in differences of visibility of the watermark and in the final size of the sheet.

B. The mould.

  1. The object of our discussion is a single mould (i.e. one of a pair) since even moulds that form a pair never are completely identical in details of the facing, or in the situation of the wire profile.
  2. During the course of the work this (single) mould is subject to changes, mainly during the couching when it is pressed upon the felt in the post.
  3. Through the repeated strain on facing and wire profile metal fatigue will set in.
  4. This occurs at first in the sewing and binding wires, but in the long run also affects the twists, the laid, and the profile wires.
  5. When sewing wires loosen or break the wire profile may start to slide from left to right or in the opposite direction, but never up or down along the chain wires, whereas
  6. the distance between the wires of the facing may also change.
  7. In this way distortions of the wire profile may appear and finally
  8. little bits of wire get detached or break off. Repairs consist of
  9. mending the sewing wires,
  10. the renewed sewing-on of the whole wire profile, or even
  11. the sewing-on of a new wire profile (of a similar design) in either the same spot, or possibly one or two laid wires higher or lower.
  12. Occasionally an old wire profile (still in good repair) was sewn upon a new mould when the old mould (its wooden frame or metal facing) had been worn out.
  13. Cases as mentioned under 12 almost resemble the differences between twin moulds, provided they were not executed differently on purpose.

C. The couching.

  1. When the coucher presses the mould upon the felt too firmly he may ‘crush‘ the wet pulp, thereby spoiling the lookthrough and often seriously deforming the pattern of laid and chain limes, as well as the watermark.
  2. When the mould slid slightly during couching the watermark became unclear and differences in size might occur.
  3. Careless couching harms both facing and wire profile and produces changes in the mould surface, as explained above in B, items 3-8.
  4. The water absorbtion of the felt also has an influence on the lookthrough of the paper.
  5. Places where the felt has been mended are often visible in the paper and may blur the design of the laid limes or the watermark.

// p. 76 //

D. Pressing.

  1. The extent of pressing influences the consistency of the paper as well as its structure or even
  2. the size of the sheet.
  3. Rash and hard pressing may crush the paper to such an extent that laid and watermark design are hardly discernible.
  4. Another effect of strong pressing may be that large-meshed felts cause their imprint in the surface of the paper and even show in its lookthrough.
  5. Heavy pressing of paper at Dutch (and other) paper-mills sometimes caused the imprint of the watermark in the left sheet-half to appear in the right one.

E. Drying.

  1. As a rule the shrinking of the sheets of paper is proportionally different in length and breadth; for hand-made paper we nowadays calculate four to four-and-a-half per cent of the long, and two to two-and-a-half per cent of the short sides.
  2. The proportion between these figures can be seriously influenced by Ute length of the fibres and their main orientation.
  3. Moreover, all sheets do not shrink in Ute same degree. Quick drying causes greater shrinkage, e.g.
  4. sheets hanging near the shutters or louvre boards in the drying loft – as also those forming the outsides of each bundle – dry quickest and therefore shrink more than Ute rest.
  5. Finally, the weather conditions – changing from hour to hour or day to day – influence Ute drying and shrinking of the paper.
  6. Alterations in the composition of the pulp (see above under A, item 7), or modified methods of retting or beating (see A, item 8) have a pronounced influence on Ute shrinkage of Ute sheets.

F. Sizing.

  1. Treatment of the paper with size and alum water and Ute subsequent drying may cause similar differences to those mentioned under E, items 1-6.
  2. The degree of influence upon Ute sheet of the thin layer of animal size covering the paper is unknown. After sizing the paper will at any rate have a better rattle and
  3. the acceptance of the writing-ink will differ considerably according to the quality and strength of the sizing ingredients.

G. Glazing.

  1. Though stone burnishing may produce considerable differences in the surface, we do not assume that it causes great changes in the dimensions of Ute watermark, except in Ute case of
  2. hammer glazing, where the sheet may stretch in both directions.
  3. This may also be the case with calendering, though the ancient calenders did not exercise Ute same amount of pressure that the modern ones do.

H. Workmen.

  1. In some cases a change of vatman, coucher, layer, presser, etc., is clearly reflected in the quality of the paper since each worker has his own habits and characteristics.
  2. In this respect the employment of an apprentice may leave clear traces.

I. Planishing.*

  1. As is generally known, early printers had to use sized writing paper which they moistened before passing it through Ute press.
  2. In the seventeenth century unsized or slack-sized printings were made to order for printers. They were easier to moisten, but had to be sized after printing.
  3. In both cases the actual planishing consisted of hammering and flattening the dent of the letterpress, after which the ready sheets were hung to dry.
  4. Moistening, sizing, and drying caused differences, as explained above (see E, items 1-6 and F, items 1-3), whereas
  5. The planishing proper – performed with a heavy hammer – had the same effect as that of the afore-mentioned hammer-glazing (G, item 2).

J. Reproduction.

  1. We should keep in mind that the dimensions of copies made on tracing paper, as a rule very sensitive to humidity, may alter due to this fact.
  2. Since reproductions of watermarks in books were as a rule copied photographically before having been transferred in letterpress or offset, small differences in size will occur in comparison with Ute original.
  3. It is a well-known fact that all copies made by means of Xerox or similar methods show minor distortions of one kind or another.

// p. 77 //

Evidently many of the above-mentioned reasons do not cause differences that can be easily ascertained, or even established at all. Nevertheless, the study of paper from the beginning to the end of a make may reveal many more differences than expected, apart from the ones that appear in subsequent makes, even though produced on one and the same mould. Anyhow, one conclusion cannot be denied: no sheet of paper made by hand is identical to the one before or the one after! If we nevertheless want to speak of identical watermarks we have to make up our minds about the differences that count and those that can be neglected. We leave this question to be answered by professional filigranologists.

* G. Piccard kindly drew our attention to these facts.

Source: Loeber, Edo G.: Paper mould and mouldmaker / E. G. Loeber. - Amsterdam : Paper Publ. Soc., 1982. - pp. 75-77 (Appendix VII). Originally published in German language: Kriterien der Gleichheit von Wasserzeichen / E. Loeber. - In: Papiergeschichte. - Darmstadt 21 (1971) 1/3. - pp. 15-17.

-- FriederSchmidt - 22 Nov 2006

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