GB191229491A - Improvements in and relating to Methods and Processes for Printing, more especially for Bank-notes, Bonds and the like. - Google Patents

Abstract

29,491. Whitehead, Morris, & Co., and Farmer, E. H. Dec. 21. Printing processes.-In order to prevent the photographic reproduction of bank - notes or other securities by either camera or contact methods, the whole or a part of the area of the bank-note &c. is provided with a design printed or otherwise formed in or upon it to produce the effect of a characteristic texture,' formed of a number of elements, such as lines, or geometric or other sharply-defined shapes or markings, which are as regards size, colour, distance apart, and relative configuration, on the one hand not sufficiently large and far apart as to enable the eye to distinguish clearly the shape &c. of the individual elements, nor on the other hand sufficiently small and close together as to be visible only as a tone or tint. Owing to halation, lenticular aberration, and other causes, it is stated to be impossible to make by camera methods anything more than an imperfect reproduction of such a design, and to prevent satisfactory contact-printing there is produced in addition to, in conjunction with, or as part of the texture, a groundwork of lines, dots, design work, &c., the elements of which are sufficiently opaque relatively to the design matter printed on the security as to prevent all the groundwork from being rendered photographically ineffective at one time, and thus to prevent a satisfactory reproduction of the design matter. Such a groundwork may be composed of contrasted colours so chosen that the photographic effect of the three primary colour sensations cannot all be suppressed simultaneously, and it may also be printed in such manner as to prevent the transferring of the design without a portion of the groundwork. The base or texture and/or the groundwork may be used to form part of the informatory or decorative matter of the note, and in addition the usual line-work or security design may be printed after the production of the composite ground base. The texture may be produced by suitably selected weavings with selected fibres or threads, or by various methods of printing. In the latter case, a large design may be photographically reduced to a sufficiently small scale; a single texture design may be printed in two or more successive positions in different colours from one printing surface; simultaneous printings may be taken in different colours from the ,intaglio and the relief parts of the block, and also, if desired, from a stencil which covers part of the block and is itself coloured on its lower surface with a third colour; the blocks may be re-etched or engraved between the successive printings; or separate printing-surfaces may be prepared from a single original in such manner as to be capable of printing in practically absolute register.