Gum printing is one method of making a photographic print. Silver gelatine is another. It is simplistic to assume that any one method represents the only true road or that any one method is suitable for only one kind of photography. I first got hooked on gum printing twenty-five years ago when I was in a similar state of mind to that of Robert Demachy some eighty years earlier, when he needed something to enliven his personal photography. Someone suggested to Demachy that he should go back to the experiments of the eighteen fifties. This was when alternatives were being sought to the ‘impermanent’ silver photograph. Demachy went back to find the gum print and went on to be one of the leaders of the pictorial movement. I went to a talk by a gentleman from Maidenhead named Steinbock. He showed me my first gum print.

Langdale 1930s Style

The subject matter was conventional; it was in the school of the 1930s salon photography known as ‘the little gem’. But the technique of this black and white print gave it a power, a tactility, a hyper-reality, that seemed to outshine many silver gelatine prints. My immediate reaction was that if he could do that in black and white, there must be a whole new world out there in colours and gradations and contrasts that I could choose for myself. I plunged in to find out for myself how to do it. It was only when I had obtained results that I found satisfactory, that I went on to find how it should be done, who had done it before and who was doing it now. Who were these oddities who worked in gum bichromate, or ‘gummists’ as they were known a century ago.

GUMMISTS

The first dichromate print was made in 1839 by Mungo Ponton who was Secretary of the Royal Bank of Scotland. But rather like Mr Wedgwood’s silver prints from the 1790s, we shall never see his results as he did not use his materials in such a way to make his image permanent.

The first extant gum prints in the UK dates from the 1850s, when the Fading Committee of the Photographic Society was deliberating. A particularly fine example is John Pouncy’s print of a country house with a couple standing by some birch trees. The print is in the RPS collection. It is a black and white print using Indian ink as the pigment. When I see the print the tactility of the surface gives the same thrill as I had when I saw my first gum print. The equivalent prints in France are by Alphonse Poitevin who was working towards a viable system of photomechanical reproduction. In fact until the advent of the computer in the printing industry machine gravure printing still depended on the effects of light on dichromates.

But collodion and albumen were more cost effective and it was found that the fading salt prints had not been fixed properly. Gum printing was put to one side. It was not until George Eastman gave ‘do it yourself photography to everybody’, that those with money, who had had it to themselves, sought something that would give their photography an extra cachet.

Contemporary art movements had had a strong effect on the world of ‘art’ photography from the beginning. PreRaphaelitism, impressionism, post impressionism, art nouveau, and the arts and crafts movement all had their part to play in the world of photography of that fin de siecle as had the great ‘straight’ photography of such as Frederick Evans. It was a fruitful time in the world of art of which photography formed part.

As gum and other pigment processes gave the photographer great control over the image, they lent themselves very much to the mood of the time. One has only to look at copies of ‘Camerawork’ or the reproductions in the Dover digest from the magazine of the Photo Secession, to gain an idea of the healthy interchange of influences. The work of Rodin, Matisse and Picasso is there with Strand, Evans and Steichen. Steichen, Stieglitz, Alvin Langdon Coburn and Gertrude Kasebier all worked in gum from time to time.

In the UK, the influential art magazine ‘The Studio’ had a periodic hardback edition devoted to photography. The 1908 edition on colour photography includes gum prints by Dudley Johnston, Demachy and a fine colour gum by Dr H Bachmann among autochromes by George Bernard Shaw and others.

The British equivalent to the Photo-Secession, with some common membership, was The Linked Ring. Margaret Harker’s history of the Secession movement in Britain, which centres on the Linked Ring, has many fine reproductions of gums by Dudley Johnston, Heinrich Kuhn, George Davison, Agnes Warburg and Demachy.

Demachy had technical mastery of the process. He knew how to retain photographic quality while producing an image with the tone, line and contrast of a renaissance drawing. His landscapes and townscapes make full use of the control over contrast that the medium gives. Sometimes his photographs of women lack taste.

Thames and Hudson’s Library of World Photography series contains fine gum prints in the volumes on ‘Landscape’ and ‘Photography as Art’. As does ‘The Imaginary Photo Museum’ published by Penguin.

But fashions changed, as they are changing now. Pure photography began to gain the upper hand. Beautiful work came from Weston and Walker. But the purist approach tends towards the parochial and the sterile in those who followed the fashionb unthinkingly. Today the computer is playing a more and more dominant role. And now reaction is setting in. Photography is now more a tool for the making of an image. It is part of the training of a painter or a sculptor to learn how to use photography as a pencil or a brush. There is less sterility. Gum and other pigment processes have become useful tools for the print maker while the photographer often wishes to return to the craft skills that are the foundation of photography.

It is this cross fertilisation of ideas, together with fine technique, that is prominent in the work of three modern gummists whose work I enjoy, Michelle Patterson worked with natural forms, shells and flowers; her work has a subtlety of tone and colour that shines from the page (but when we last met she had taken up white water canoeing instead). Christine Rendina often works with the formal lines and warm colour of the Moorish architecture of Spain. She applies colour differentially using superimposed lith images to great effect. Lyn Silverman has the power to abstract the essence from a scene and present it with delicacy. Of these Rendina’s work is probably best known. All three deserve wider recognition.

St Margarets on Thames

THE PRACTICAL FOUNDATION

My early experiments showed that, after cyanotype, using a contrasty negative to make a gum print, is the easiest way to make a photograph. And if that is the peak your of ambition, then fine. But like the cyanotype, if you want any subtlety, you will need to apply photographic expertise and experience. In the case of the gum print you will need it by the ton. Also, you will need to be bull-headed and persistent as there are so many variables and so much that can go wrong.

That was a health warning. But the end result of your persistence can be so exciting, and give you so much freedom from the parameters laid down by the chemists and the purists, that silver gelatine may seem lack lustre, and only two other photographic printing methods may seem worthy of serious attention, platinum and gravure. But even then great enjoyment can be got from the other processes requiring contact negatives, such as kallitype, salt printing and cyanotype. These lead on to pigment printing and bromoil, carbon and photo-etching. And then for good aesthetic reasons you can go on to combine them.

One of the joys of the gum process is that there is no one right way of doing it. The method you establish will reflect your own personality and way of working. But do not try it if you are tense or in a bad mood.

If you are the kind of person who needs to be told precisely what to do, you have probably given up reading this already. What I intend to do is give the recipe, details of the materials and their sources, the basic working method and a few useful hints. It is then up to you to go away and make your gum print, although the cross fertilisation of ideas that one gets on a workshop or on the altartcraftphoto list on the net can save a great deal of effort. If you are the kind of person who can paint a front door with gloss paint, or who can bake a Yorkshire pudding, there may be some hope for you.

INGREDIENTS

Dichromates

HEALTH WARNING

• The dichromates, formerly known as bichromates, are cumulative poisons that can be absorbed through the skin.
• The dust can eat away the mucous membranes, e.g. in the nose and lungs.
• They are cancer suspect agents. As with all chemicals, treat them with respect. Wear gloves.

Potassium dichromate (K₂Cr₂O₇) can be dissolved to the extent of one part in eleven in water.
Ammonium dichromate ((NH₄) Cr₂O₇) can be dissolved to the extent of one part in three in water.
This is the maximum amount that can be absorbed and is known as a saturated solution.
The ammonium compound is three times as nasty and three times as fast.

Light

You need ultra violet light which you can get free from the sun but it is not as consistent as one might wish. The most effective wavelength is in the near UV range a little below 380nm, a wavelength which is not blocked by standard plate glass. Visible violet light starts at around 400nm. You can use a bank of backlight fluorescent tubes in a light table but mercury vapour UV graphic arts lamps give an even spread of light from a single bulb. I use a Phillips HPR 125 MV lamp which is designed to give a series of peaks four different graphic arts processes. UV ‘health’ lamps and sun beds also work.

Brushes

You will be spreading gum, which watercolourists use as a lacquer, onto watercolour paper, accordingly the recommended brush is a water-colour lacquer brush; Omega, series 40 with a code number which gives the width in mm. The brushes are described as ‘Pura Setola’. Sponge brushes may also be used. Hake brushes can be used for spreading the gum and for selective removal of the gum in the course of the development process. ‘Hake’ means brush.

Gum

Gum arabic comes from a tropical acacia tree. Winsor and Newton sell prepared gum arabic which is expensive but is of the right consistency (17° Baume, a measure of specific gravity for heavy liquids, which for gum corresponds to its viscosity). It is good for your first experiments. You can buy a very expensive version in lumps together with bits of tree, which is known as royal gum arabic. You have to dilute it 50/50 with cold water and filter it. White gum arabic powder, diluted 1:1 with cold water and left to dissolve, achieves much the same effect. Liquid gum arabic, sold as an etching resist also works. Stevens' Glue is gum arabic but its brown pigment degrades whites. Gloy gum, available in Europe but not in the USA, is a mixture of PVA and PVC with surfactants; it is three times as fast but not so subtly controlled. You can use other organic colloids derived from milk or eggs, as examples.

Pigment

Use strong permanent artists’ water-colour in tubes from Winsor and Newton. The more pigment you use the less chance the light has to do its work. That is why you need strong pigments. A basic palette should include red, alizarin crimson; blue, cobalt and indigo; yellow, new gamboge; green, sap green; burnt sienna for brown and neutral tint and ivory black. Lamp black, which is kerosene soot, tends to oil its way into the paper. I prefer to use neutral tint or, if a very dense black is needed, I mix a powder pigment directly into the gum. Avoid pigments that stain such as the Hookers greens. You will be coating the whole of the paper before each exposure and then washing away the gum that has not been insolubilised and that you do not want. A staining pigment will contaminate the whole of the image area.

Film

The gum emulsion is very slow and is only capable of accepting a density range of about 0.7 at a single exposure. You will need to make contact prints and give more than one exposure if you wish to obtain a wide range of tones with good gradation. You will need to have negatives the same size as your final print, If you are intending to make 10x8 prints there is no problem, use medium speed camera film either direct from the camera or enlarge onto it on the baseboard from a transparency. For larger sizes use graphic arts films. Lith and line films can be used but they should be exposed and developed for continuous tone unless you are looking for line results. I recommend heavy base films, as thin films do not maintain stability where more than one exposure is required. Paper negatives can be used to save cost for the larger sizes; the image on the paper negative will need to be laterally reversed; the exposure onto the gum print made emulsion to emulsion and increased by a factor of three. Ink jet negatives are perfectly adequate either on acetate or on standard ink jet paper. For more ‘graphic’ results use photocopies.

Other tools

A 5cc spoon from the pharmacy, long bladed plastic or steel palette knives and a white ceramic tea plate as your palette, map pins and drafting or magic tape, a contact printing frame or two pieces of 5mm Plate glass.

Other Materials

Size, potassium metabisulphite (from home made wine departments).

PROCESS

This process, and much photomechanical printing, depends upon the reaction when a dichromate salt is mixed with an organic colloid, e.g. a gum or gelatine, and how that reaction is speeded up when the mixture is exposed to light. Put in terms that I can understand, the gum molecule is a flexible chain of hydrogen and carbon atoms with oxygen side spurs. The dichromate molecule can be excited by light at the right wavelength to throw one of its oxygen atoms which fills in the gaps between the spurs on the gum molecule chain. This stiffens the chain and the resulting stiff gum becomes insoluble in water. The more the light or dichromate, the greater the insolubility and the less the contrast. The less the light and dichromate (and the more the pigment) the greater the contrast. After exposure and development the insolubilised gum. which is porous, retains the solid particles of pigment, while any remaining dichromate in solution is washed away, Well that was fairly simple. Remembering these principles should enable you to answer most of the problems you will meet.

METHOD

For a monochrome, e.g. black and white, or multicolour three exposure 16x12 print with a wide range of tones. If you are using a film negative that contains the necessary information, that negative can be used for highlight, middle tones and shadow detail. I make separate paper negatives, however, for each range of tones. As in the rest of photography, if you get the negative right, everything else falls into place.

1. Squeeze pigment about the size of a petit pois onto your tea plate, add 5cc of gum and mix thoroughly using palette knife. (Some people use gum ready mixed with colours to particular densities which they store using toxic preservatives; this is an unnecessary complication which restricts freedom of operation and is potentially dead making.)
2. Add 5cc of saturated dichromate solution and mix thoroughly.
3. Tape down paper to a smooth surface and mark off area to be covered by negative. Coat paper with a lightly dampened brush using smooth caressing strokes being sure not to abrade the surface. This may be done in subdued light.. Your objective is an even surface.
4. Place in the dark to dry for at least forty minutes until there is no trace of tackiness or shine on the surface. Remember that the chemical reaction is only speeded up by light. It continues in the dark to the extent that you should not be surprised if results from sensitised paper stored for more than twelve hours prove unsatisfactory. I am told that it will last longer if you store the paper in the freezer.
5. Place the negative, emulsion side up, on the sensitised paper . If your sensitised paper is still not dry it will stick to your negative. Avoid contamination by putting a thin sheet of acetate between the negative and the sensitised paper. Somebody I know has been known to take a kitchen scourer to a contaminated negative without adverse effect on the final picture. Tape the negative to the paper outside the picture area. Make two holes through the margin of both using the map pins. These holes will serve for registration.
   
6. Exposures here assume a negative suitable for grade 2 silver gelatine paper with the work piece, coated with Gloy gum and ammonium dichromate, at 18" from an HPR 125 Mercury vapour lamp. Your first exposure should be between 5 and 15 minutes depending on the negative. Tests are advisable. If you are using pigments other than strong blacks , the image should print out. If it does not look as if it's done enough, give it a bit longer.
7. Develop in lukewarm water to wash away the uninsolubilised gum to the desired level of contrast. Do not delay development as the reaction is continuing even after the light has gone out. Floating the print upside down on the surface of the water is known as automatic development. You have to wait until you can see the pigment falling off. Using a wet soft brush gives you greater control as does directing streams of water at those parts of the print you wish to affect. Remember that one extra minute under the lamp means ten extra minutes of development. You are developing for detail in the highlight areas.; do not attempt to make this first exposure look like a finished print.
8. Dry in a strong stream of warm air. If you have significant areas of highlight, and you have not applied a hardened base, resize between coats. Redry.
9. Recoat, using more pigment, for the middle range of tones, then repeat 3 through 8, but the exposure should be one third of that at 6, or less. More pigment means more ‘black’ or more of a colour suitable for the middle range of tones.
10. Repeat using more pigment and a shorter exposure for the shadow detail.
11. Dry, fix in UV light for a short time, and wash for six hours. If you are impatient to see the final colours quickly, uncontaminated by the orange of the chrome salts, place the print in a clearing bath of potassium metabisulphite. The stronger the solution, the quicker the clearing. I just use water.

There are many other ways of making a gum print. Some are more complicated to achieve different aesthetic results; others satisfy the need of the proponents of complication. Yet other methods depend upon cumulative misreadings and misunderstandings of writers on the subject for the past one hundred and fifty years. As I delved back in my own researches, I found the same mistakes repeated each time there was a revival of interest. It became clear that those writing the articles had never made a gum print. I reinvented the process for myself to keep it simple and avoid deadly poisons such as mercuric chloride which some use to kill off the bugs in their gum. There seems to be as much chance of killing yourself. Make fresh as you go along.

For me, the picture is the objective, not the process.

Base of Saxon Cross on Yorkshire Moors

HOW TO BOOKS

By searching around in old bookshops it is possible to find many articles and books on old processes including gum. Be warned of the look it up and copy it out tendency which leads to distortions over the years. Also be warned that there is a very strong tendency among those who dabble in old processes to overcomplicate to the power of ‘n’.

SOURCES

(These sources are for the UK. I will be happy to add further information for other countries or geographical areas if someone is prepared to give me similar list). The following sources of materials are those that I have found give good and reliable service. They are not exclusive. If there are any suppliers not on this list, outside London for example, who can offer a similar service, I would be glad to hear from them.