What’s new Paper and artpaper A new linen paper for all siderotype (iron-based) processes

A new linen paper for all siderotype (iron-based) processes

Writer and photography / Dr. Mike J. Ware

Mike Ware tests out the new Ruscombe Mill papers – papers he has also helped develop especially for processes such as cyanotype, argyrotype, palladiotype, platinotype and new chrysotype.

To friends and colleagues in the ‘ferric practices’ – as you’ll know only too well, the last technical difficulty confronting us is the uncertain quality and composition of the paper stock that we coat. Everything else lies within our control.

In recent times, I’ve heard that the commercial supplies of cotton furnishings for high quality papermaking have become increasingly unreliable, sometimes causing problems in the changing characteristics and supply of some of our most popular papers for hand-coating, such as Arches Platine and Bergger COT 320.

Siderotypes on linenI’ve been personally associated with a 100% cotton handmade paper called ‘Buxton’ paper, from Ruscombe Mill at Margaux – for the benefit of any non-winebibbers among you (if that’s possible?) it’s in the South-west of France. I’m therefore pleased to inform you that a new paper has recently been developed by Ruscombe Mill, and should become available by the end of April, this year. The launch of this product and purchasing details will be announced on the Mill’s website.

I’ve tested Herschel paper with argyrotype, new cyanotype, palladiotype, platinotype and new chrysotype. It performs superbly with all these processes as I practice them – better even than Buxton paper in some respects, although it will cost no more.

Cotton fibres
COTTON is a ‘seed fibre’ from the seed hairs of Gossypium hirsutum. The fibre has an average length of 25 mm and a width of 0.019 mm. Its appearance is of a flat ribbon with an internal cavity (the ‘lumen’), rather like a deflated inner-tube of a bike tyre, which is twisted in the unprocessed state.

“The processes and raw materials we use have enabled us to develop and manufacture the Buxton 100% cotton paper to Mike Ware’s recommendations since the mid 1990’s. “

– Chris Bingham, Ruscombe Mill Handmade Paper

I suspect – but don’t have the means to prove scientifically (an electron microscope is beyond my means!) – that the different performance of flax versus cotton cellulose lies in the fibre morphology constraining the image substance (see second attachment). The structure of the flax fibre may enhance its ability to retain nanoparticles of image pigment, which is essential to the success of all siderotype processes. During the wet processing, I don’t see any “bleeding” of image substance – even Prussian blue, which is notorious. I’ve been particularly delighted with the colour of the silver images it yields with my argyrotype process, and the range of colours obtainable with new chrysotype, which are also highly dependent on particle size.

Herschel paper, like Buxton, is ‘engine-sized’ with neutral alkylketene dimer, AKD. It can be rod-coated with sensitizer solution similarly to Buxton, with the addition of Tween 20 surfactant to the sensitizer, to ca. 0.1-0.2%. There is, of course, absolutely no added chalk buffer in this paper, which seriously inhibits siderotype, no surface sizing such as gelatin, which ‘kills’ platinum, nor clay or gypsum fillers, OBAs, etc., etc. With all processes, the Dmax is high, the cold-pressed surface is perfectly matte with a ‘fine tooth’ texture, the clearing of whites in the wet processing is rapid and complete, and the gradation and smoothness of the image tones are excellent. This linen paper sheet has much greater resilience and wet strength than cotton papers, notwithstanding its moderate weight of 200 gsm. Dimensional stability is good, with about ±1% hydroexpansivity; but to obtain a perfectly flat sheet after processing, it does need to be dried under pressure.

Flax fibres
LINEN is a ‘bast fibre’ from the stem of the Common Flax plant, Linum usitatissimum. Its fibre has a similar size to cotton, but is cylindrical with a thick cell wall and an internal cavity (the ‘lumen’) of relatively small diameter. It has periodic knots or nodules, so resembles bamboo. When beaten it fibrillates more extensively than cotton, so forms a stronger, less elastic paper sheet.

‘Herschel’ paper will prove an excellent replacement for Buxton, with the advantage that the Mill’s supply of linen cellulose fibre (from flax grown in Northern France or Belgium) is more reliable and consistent than present supplies of cotton. In high quality papermaking, confidence in the raw materials is paramount. One need have little worry about archivality, because linen was the first plant fibre historically available to Europeans for making fabrics. Long before the growth of the cotton textile industry towards the end of the 18th Century, linen rags were being processed in the 15th Century for European papermaking, and such papers have endured well to this day. I believe that linen papers have also been used for banknotes, bonds, and other security papers.

Mike Ware is a british chemist and inventor of the New Cyanotype process – amongst others and an author of many books.

To find out more about these papers, go to Ruscombe papers website

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