AlternativePhotography.com : Bromoil and Oil Pigment Printing

Bromoil and oil pigment printing

A description of the process.

Always be careful when handling chemicals. Read the health and safety instructions.

Image left: The End of Maerdy Colliery South Wales - bromoil

Bromoil was developed in the early years of the century to enable 'control' to be exercised over straight black and white silver prints. It superseded oil prints which worked on the same principle but required a contact negative. Both the bromoil, (bromide plus oil), and the oil pigment print depend on the lithographic principle that wet rejects oil and dry accepts it. If the gelatine in a photographic print is treated so that the shadows are tanned, that is made less able to swell when soaked in water, then the shadows will accept oil based inks and the highlights, replete with water will reject them.

Pigment Print

An oil pigment print is produced by coating water-colour paper with three layers of gelatine, I use photographic gelatine of about 260 Bloom) first a 5% solution and then on drying, first one and then another 7% solution. There are many different ways to achieve good results. I use two different methods of coating. The first is to make up a tray of the gelatine at the appropriate dilution. The gelatine must be kept at above the melting point of gelatine, about 104 F or 40 C. The paper, I use a 300 gsm watercolour paper, is immersed in the gelatine for three minutes for each coat. Agitate the gelatine bath to avoid the development of bubbles. As you remove the paper from the tray wipe the paper across the edge to remove any last hint of bubbles. Hang the paper up to dry in a flow of warm air. Repeat for each coat. Alternatively coat the paper with a hake brush but make sure that the gelatine is above the melting point of gelatine and flows well. Repeat for each coat.

There may be an advantage in adding a very small amount of chrome alum to the 5% coat but not subsequent coats. The alum helps the 5 % coat to bond with the paper. The amount used should be very small; in old terms a one grain solution, that is one grain to a fluid ounce or .05 g in 30 ml, which can be added to a litre of the warm gelatine.

When this has been sensitised using a 2% solution of ammonium dichromate in water, or a 3% solution of potassium dichromate, at 17C , allowed to dry in the dark and exposed under a negative, and then washed for an hour, finishing with warm water (under 38C), the resulting gelatine matrix will be ready to receive ink in the same way as the bromoil matrix the recipe for which follows.

Image above: Bromoil prepared with sponge decorators' roller

The pictures here were made on Kentmere Document Art which is a b&w printing paper with no supercoating made for subsequent painting and drawing on the photographic surface; that paper is currently unavailable although a replacement will be available in the spring of 2007. Paper made specifically for bromoil printing will also be available through Terry King but you will need to let him know in advance how much you need and of what sizes. At the moment, one needs to use supercoated papers where the soak water has to be kept hot. Make a slightly overexposed print such that the highlights are lightly veiled. Avoid large areas of very dark tone.

Develop using a developer containing no caustic soda, eg Ilford PQ Universal.

Rinse.

Fix in a 10% solution of plain hypo for 10mins.

Wash for three hours.

Blot off until no dampness shows.

Dry in warm until crackly.

Soak in cold water for five minutes.

Bleach in a 50 % solution of the stock solution: recipe for bleach stock solution:

a) 750 ml water
b) 10 ml 28% acetic acid
c) 30g copper sulphate
d) 30g potassium bromide
e) 2g potassium dichromate
f) water to 1000ml until shadows remain as a pale green trace

If you have a pale red trace your print, on which you have worked so hard should be placed, very carefully, face down, in the round filing cabinet...

Wash for 10 minutes.

Fix in 10% hypo for 10mins. If you do not fix at this stage your silver picture will reappear!

Wash in running water for thirty mins.

Soak in warm water (100F) for twenty minutes or until relief image shows.

Swab to remove scum.

Dry.

Resoak at room temperature until relief shows.

Blot until there is no sign of surface dampness.

Image left: Downs - bromoil

From this point the processing of the bromoil and the oil pigment print are the same:

Spread a little oil based litho ink on a piece of glass and with light dabbing motions of the brush transfer ink to another part of the glass; work from the transferred area.

Ink up, using a Boots imitation badger shaving brush*, with a dabbing motion and very little oil based lithographic ink, only on the very tips of the hairs of the brush, until the whole image is covered (better results can be obtained with genuine bromoil brushes with a stags foot shape and fairly soft hair; modern bromoil brushes that I have used proved a little too hard ). Highlights need softer ink achieved by adding a drop of plate oil (boiled linseed oil) to the ink before it is spread on the palette. One can even use a spotting brush for the highlights if the ink is of the right consistency. Ink for the shadows can be stiffened by adding a tiny amount of light magnesium carbonate.

* The student who used her husband's amber handled genuine badger hair shaving brush was not seen again.

Remove ink using an oblique light stabbing and twisting movement.

Repeat 18 and...

Resoaking and reblotting from time to time to maintain the water level in the gelatine until the picture is completed. (a smoother effect can be obtained by inking up using a foam sponge decorators roller); The brayer needs to be of very high quality preferably hardened gelatine. The last time I checked the cost of such a brayer, it was about three times the bucket shop return air fare from London to New York.

Leave the print for some days to harden. After the print has hardened it is easy to introduce local colour with oil pastels using small shavings rubbed in with the finger to obtain delicate shading.

Alternatively run the print face down onto soaked printing paper, between a sandwich of lintless blotting paper, through an etching press. This will give a bromoil transfer. Re-ink and repeat for an edition of up to twelve prints.

There is no guaranteed method of removing the ink. For example very delicate manipulations can be achieved by working with the work piece under the surface of the water. Synthetic bath sponges can prove very effective,

The "tool" for blotting can be lintless blotting paper from art print suppliers or cotton wool from the pharmacy but be careful to avoid leaving strands on the print. The light magnesium carbonate is sold at pharmacies as some use it as a foot powder for sweaty feet. Plate oil is also available from art printing retailers who are, of course, the source for lithographic inks in a wide range of colours.

There are many different methods which can be adjusted to suit one's working methods or personality. It is worth adding that over the years a pattern has emerged that accountants are usually good at oil prints and bromoils. This observation arises from a very small sample and is almost certainly not statistically significant.

The Old Ghetto, Venice - bromoil

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Bromoil and oil pigment printing

A description of the process.

Pigment Print

From this point the processing of the bromoil and the oil pigment print are the same: