Conserving the Proeschel Atlas: paper and printing
Part 2 in a series on the Proeschel Atlas conservation project
8 October 2013
This is part two of a series on the conservation of each copy of Frederick Proeschel’s Atlas containing a map of Australasia, 1863 in the National Library. Part one focused on the Bindings. This part focuses on the paper and printing used for the atlases. The examination and identification of the paper and printing techniques gives me a better understanding of how the contents of the atlas were made, why specific deterioration has occurred and what to take into consideration when deciding the final conservation treatment. To begin with, a simple collation was formulated to ensure that nothing was missing or placed in the wrong order within any of the three copies being conserved during the Proeschel Conservation project.
Elaborately illustrated title page of Atlas of Australasia, 1863
This collation was also used during the examination of another copy held within the Map Collection of the British Library, London. Their copy is believed to be the one deposited in the British Library (when it was still part of the British Museum) in 1863 by Frederick Proeschel. Fortunately, the contents were found to be identical to The National Library of Australia’s copies. This confirmed the atlases requiring conservation were all in correct order and the examination of the maps and text leaves could proceed. Each atlas is composed of six small and large coloured maps and 24 descriptive leaves of text printed in black ink. The paper substrate used for both the maps and leaves were examined as well as identification of the printing processes used.
Large hand-coloured, foldout map of South Australia on a smooth, pale paper; Preface in black ink only on a biscuit coloured paper.
Identifying the paper
Two distinctly different paper types were used for the maps and descriptive leaves. The paper used for the maps (as well as the title page) is composed of a mould-made, wove paper fibre arrangement with a smooth surface finish. The smooth surface suggests the addition of internal filler, such as white clay, during the paper making process which also gives the paper its pale appearance. A smooth paper is required for the even transfer of ink from planographic (flat surface) printing processes such as lithography to the dampened sheet of paper. Lithography was often used at this time for printing highly detailed maps and illustrations. The descriptive leaves are printed on a mould-made, wove paper with a rough surface finish. The rough surface is promoted by the use of felts for the final stages of the drying process without additional flattening between two smooth surfaces. The rougher surface being suitable for relief processes such as letterpress printing that required much greater pressure to transfer the inked lettering to dampened paper.
Wove paper used for maps on left next to sheet of laid paper; Smoother surface finish to paper used for maps. Magnification x50.
Wove paper used for text leaves on left next to sheet of laid paper; Rougher surface finish to each sheet of paper used for text leaves. Magnification x50.
The fibre identification was conducted with the assistance of Travis Taylor, Conservator, National Archives of Australia, using small fibre samples taken from different paper substrates within each atlas.
Travis Taylor performing fibre identification
Cotton fibres from Map of South Australia; Many broken ends of cotton fibres. Magnifiication x200.
The analysis began with a few fibres used for the map of South Australia – typical of the paper used for the maps. This was found to be a mix of cotton and linen fibres as sourced from textile rags, often referred to as rag fibres. As Travis points out in his website “Cotton fibres are smooth, ribbon like and easily identifiable by their twisted nature. Immature fibres are often not twisted. Fibre ends are often broken, although they sometimes exhibit tapering tips.” Many of the fibres examined showed signs of deterioration as can be seen in their splitting and breaking. The orange-pink colour change also confirms the presence of cotton and linen fibres. These are archivally stable fibre sources so should not dramatically age if kept in a suitable storage environment.
Esparto fibre among orange/pink rag fibres in text leaves; Rag pulp fibre from Preface. x200
Several images were taken of the fibres used for the text leaves as several fibres types were found. There was evidence of rag pulp mostly as a mix of cotton and linen as thick, ribbon-like fibres which was verified by the orange-pink staining. Also present was grass or softwood pulp as indicated by the blue-purple colour change to some fibres. One image revealed one of two epidermal cells similar to esparto grass – one of which can be seen in the left hand image above. Esparto was first used by Thomas Routlege, Eynsham Mill, Oxfordshire and gradually adopted across Britain when he took out patents for processing this grass in 1856 and 1860. This would be an exciting find if further examination confirms that some of the paper fibres used for the text leaves contained an early example of esparto grass in paper making. Proeschel had previously experimented with different plant fibres for stuffing matresses, so it may be possible that he was keen to use paper containing a modern paper fibre like esparto grass. The inclusion of the grass and softwood pulp means the paper is more prone to becoming brittle and easily damaged if not stored appropriately.
Printing the maps and descriptive leaves
Using a digital microscope, the examination of the printed areas of both the maps and text leaves helped to identify which intaglio printing (incised surface), relief printing (raised surface) or planographic printing (flat surface) techniques were used for the atlas. Most text printing in a book was done using the letterpress technique until the end of the nineteenth century. The crisp black lettering and the ink sitting ‘raised’ on the surface of the paper used for the preface and other leaves examined is characteristic of the letterpress relief technique. This meant that every letter of every word was assembled by hand into a frame and attached to the press for printing.
Preface printed in letterpress – print sits raised on the paper. Magnification x50
Title page printed with Lithographic Transfer Process - print appears flat and less crisp on the surface; Detail of lines used in map of Victoria. Magnification x50
Examination of the printing of the title page and maps revealed a flatter transfer of the inked letters and lines to the paper confirming the technique used was characteristic of the lithographic printing process. Using examination and previous research from both newspaper articles and Proeschel’s correspondence, confirmed the maps were printed in a two stage process known as Transfer Lithography. This simply means transferring the many lines and letters from the copper plate engraving (intaglio) to a lithographic stone for printing many times over. Lithography being a process invented in the late eighteenth century and undergoing many developments such as transfer lithography from engraved plates. Maps printed using the transfer technique can at first be difficult to distinguish from copper plate engravings but under a microscope the flatness of the ink on the paper can be seen.
Detail of hand-colouring and printed lines from the map of Victoria. Magnification x50
Detail of bleeding watercolour from the map of Victoria. Magnification x50
All maps were printed using black lithographic ink and hand colouring. As can be seen from the low magnification images of the map of Victoria above, hand colouring with watercolour paints often results in a slight bleeding as the paint is pulled beyond the printed black lines by capillary action within the paper or overlapping of the colour using a brush. If coloured inks or pigments are transferred using a mechanical process the colour placement is usually more accurately within the limits of the black printed line. The printing credits do not follow the tradition of naming the illustrator or artist del (he/they drew), lithographed by lith (he/they) followed by Imp for printer. Instead ‘ Brown & Slight Engravers and Printers’ is highlighted in a small frame on each map. But this does not give credit to who actually undertook the engraving and who performed the transfer and lithographic printing of the maps and title page. For further reading on this topic you may be interested in these works in the NLA collection: