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Growing Your Own Ink Testing Armed with a sizable batch of samples, along with the fruits of my historical researches I began to identify those species that might most profitably be used for ink production. I should say that at this stage I was beginning to consider the possibility of producing ‘process’ colours for full colour reproduction work, so I was particularly on the look out for blues, yellows and magentas. The idea of trying to make process colours was suggested to me by two particular features of plant colourants. One being the fact that however strong a plant colour might be, it is always essentially transparent in nature, so the possibility of producing opaque inks rivalling those of the oil-based variety is simply not possible. ‘Process’ or ‘trichromatic’ inks however depend on transparency for their effect, so this seemed a useful direction to take, particularly as, and this was probably my second reason, the slightly potty marriage of an ancient, low tech process with the ultra-modern laser scanning colour separation technique, simply appealed to my contrary nature. Much of the literature devoted to traditional dying techniques (eg. William Partridge’s ‘A Practical Thesis on Dyeing of Woollen, Cotton, and Skein Silk.’ of 1823; Thomas Cooper’s ‘A practical Treatise on Dyeing and Calico Printing,’ 1815; and Samuel Parkes’ ‘Chemical Essays’ of the same year) proved very useful, in so far as the procedure for extracting colour from plants is almost the same as that followed by those wishing to dye yarn or material. The differences lay firstly in the obvious requirement that fabric dyes should be wash-fast, and this is not normally a necessity when printing on paper. The second difference is in the need to transform what is essentially coloured water into an ink of the right viscosity for screen printing, the employment of suitable thickeners in other words. But first let us deal with the process of getting plants to release their colour. Extracting the colour Two recent books on the subject of plant colour extraction are worth mentioning here; ‘A Dyers Manual’ by Jill Goodwin (1982), and ‘Dye Plants and Dyeing’ by John and Margaret Cannon (1994), provide a good deal of information about which plants give colour, and most importantly, how to extract and modify those colours. Extraction is very simple, and a few basic rules quickly become apparent. I started by soaking plant material, then simmering or boiling it to release the colour. Boiling is not always advisable, particularly with reds, as some tend to become more brown or even disappear when boiled. Thus if you know that a certain plant should produce red then my advice would be not to heat above 800 C. until you’re sure it won’t spoil the resultant colour. Most plants do in fact produce some colour especially in soft, or artificially softened water (by adding washing soda, Sc), but many are simply too dull, weak or uneconomic to persist with. Not all samples need to be soaked, but most benefit from at least 24 hours in water. Even soft fruits like blackberries and raspberries will benefit from some pre-soaking, though soaking really does become essential with hard fruits, leathery leaves, barks and woody roots. The effect of soaking on plant material, ie. to help break down its cellular structure, can also be achieved at least for fruits, by a spell in a micro-wave (J&M. Cannon, 1994) or by deep-freezing (though I found the latter seemed to be detrimental to some samples, diminishing the intensity, range and yield from mahonia (Mahonia aquifolium), elder berries (Sambucus nigra) and other soft fruit). I simmered or boiled most of my samples for periods of between 20 to 60 minutes. When a plant does release a flood of colour it really is quite exciting, especially as the colour released often bears no resemblance to the colour of the plant itself. The effect is quite magical when the berries of Selenium scabrum (a relative of the potato) releases not one but eight separate and distinct hues, from a cerulean blue to magenta, purple and green!
Phil Shaw MA(RCA) |
