Pigments and Solutions

I pledged to share my research as part of my current Arts Council project; the only thing I’m finding is that now I’m well and truly immersed in exploration, it’s become difficult to know what exactly is useful and worthwhile to share!

The freedom to experiment has encouraged me to dabble with materials and processes all over the place, but I seem to keep returning to recurring themes. Yet again I find myself attempting to extract the ‘essence’ of various things; all of them objects with a capacity for being imbued with any amount of personal significance. This week the objects have been flowers. I’ve always been interested in capturing the soul of things. My Fabric of Life project was a series of portraits of people from my local community, painted upon fabric which they had donated.

This could have been an old item of clothing imbued with deep emotional significance and memory, or furnishing fabric remaining after the redecoration of a home. Clothes, furnishings, fabrics and patterns provide unique clues to the identity and personality of their owner. By using fabrics with a past life within my painted portraits I desire to capture a depth of substance and facets of character which paint alone cannot describe.

In addition, clothes and furnishings are transient by nature, but once captured and preserved within an artwork they attain a new level of permanence. I think this is what has also interested me about flowers; they often mean so very much (think of wedding bouquets and the Victorian’s language of flowers LINK), and yet their existence is so incredibly fleeting. But what if I could extract the essence from a flower and preserve it forever?

For me as a visual artist, an object’s essence is definitely made up of its pigment or colour. Surely if each species of plant and flower is unique, this must mean they contain their own personal series of pigments within their leaves and flowers? In this way, I suppose the colours extracted from a particular plant species to be some kind of unique fingerprint in a combination specific only to that one species.

So how to find out? I remember extracting chlorophyll from leaves in high school chemistry lessons; mushing leaves up in a beaker filled with solvent or alcohol. This seemed as good a place as any to begin.

I mashed up leaves and blooms in acetone first, then repeated the process using surgical spirit and alcohol (vodka). Varying quantities and concentrations of pigments were obtained as a result. However the colours were pretty disappointing, being neither strong nor bright. I decided that more research was needed.

Websites on natural dyes and dying were my next useful source of information, advising to boil the plant material in water for an hour and then let stand overnight at room temperature to extract the maximum amount of pigment. I tried this but once again wasn’t impressed by the results. Further improvements were still required, and so I contacted my collaborative chemist for assistance.

Apparently there are three main methods of successfully extracting pigments from plants: the acidic method, the alkaline method and the alcoholic method. Of these I intend to try only the second two, as the acidic method involves boiling hydrochloric acid; something I don’t think is very advisable to try at home! The alcoholic method can be easily done by boiling the plants in a solution of alcohol (I intend to use surgical spirit). The alkaline method is similar, boiling the plants in a solution of sodium carbonate. The chemist has assured me this is a fairly benign process as long as I have adequate ventilation. A variation of the alkaline method can also be done using a solution of sodium hydroxide… this is otherwise known as caustic soda- I won’t be boiling that in a hurry!

Watch this space for the results… I’m off to the hardware store now for my supplies.


Childish Experiments #2

In my quest for a solvent which can remove newsprint ink from newspaper I’ve been doing a bit of online research. Whilst doing this I’ve rediscovered an activity I remember from my childhood. It wasn’t so much an experiment, more an interesting discovery, that Silly Putty (the fascinating, mouldable, semi-solid goo in a plastic egg) will pick up the text from newspaper when they are both pressed together.

So as a child I would go around collecting text and images from newspapers on my flattened Silly Putty, then squishing the putty together until the writing had gone. I’d repeat the process over and over until the olive green putty turned black from all the blended ink. I don’t remember ever wondering why the transfer of text was so successful with the putty, and yet didn’t occur when using other mouldable substances such as clay. It turns out there is a scientific reason for this. It’s all to do with the solubility of the ink.

A rule of thumb for solubility of two substances is “like dissolves like.” Polar substances (such as water or alcohol) will dissolve other polar substances. Likewise, nonpolar substances (such as oil and fat) will dissolve other nonpolar substances. However, polar and nonpolar substances (oil and water) do not dissolve in each other. Newsprint ink is a pigment suspended in oil (a nonpolar substance) which is adsorbed by the paper. Since Silly Putty picks up the ink from the newsprint, it must also be a nonpolar material. The pigment-oil suspension of the newsprint ink is readily adsorbed by Silly Putty. Our oily skin often picks up newsprint for the same reason.

From this, I can conclude that inks which the Silly Putty cannot pick up are polar substances and therefore are not readily picked up by the nonpolar Silly Putty.

So does this then give me a clue as to how to dissolve newsprint? Nonpolar solvents, as a rule, sound pretty unpleasant to me…

At least this discovery has started me thinking about testing a greater range of solvents to discover which may share the polarity with the various inks and pigments I have been using. So far I’ve tried numerous household cleaning solutions, as well as acetone, surgical spirit and white spirit, with varying success. My next batch of experimentation will be with various inorganic salt solutions; beginning with table and Epsom salts, and then progressing away from the commonplace and further into the world of chemistry. I’m curious to see how they may react when placed side by side with a selection of pigments, inks and solvents… *dons mask and gloves*


Childish Experiments

With a research and development project it’s sometimes hard to know where to start, for with so many possible avenues to explore, the possibilities are endless.

A recently rediscovered book from my childhood has been supplying me with my current inspiration. It was written in the 1980s, an era in which, I guess, we as children must have been much more innocent and easily pleased than the children of today. Activities include such gems as how to make a mouse and twirling ballerina out of a pocket handkerchief. My attention was caught however, by a recipe to make an image transfer medium using white spirit and soap.

While I can’t say that the images I transferred using this method were entirely successful, they have led me to an interesting line of enquiry around the capturing of images for insertion into resins.

I’m particularly keen on the idea of physically ‘capturing’ the ink from a page as opposed to reprinting or copying the page as I love the idea that the removal of the ink and its encapsulation is extracting and preserving the soul or essence of the book/newspaper/printed words; somehow more pleasing to me than simple reproduction. My next step will be to experiment with solvents/alcohols to see whether I can dissolve the ink from the page. Any suggestions as to what may work would be gratefully received!