PHOTOGRAPHY

Auckland Star, Volume XLIV, Issue 177, 26 July 1913, Page 15

PHOTOGRAPHY

THE OIL PROCESS. A process closely allied to the gumbichromate printing method is what is known as the oil process, ll ha* been Classed as essentially an artUt's process, and certainly it admits of so many vari- j ations. ailu so much individual treatment that along with the gum process ii provides the very medium for the pictorial worker who prints directly from the negative, enlarged or otherwise. While it is quite possible to make one's own oil pigment paper- and this is a practice which many advanced workers adopt - it is beiu-r and cheaper for a beginner to buy al his dealer's a supply of one of the ready-prepared papers which arc on the market. Some sub- j ject.s can stand a very rough surfaced j paper, while others require a -mouther sort. Again, it may happen that a cream-tinted paper suits the particular case: no hard and fast rule i-an he laiil down. Everyone is free to indulge in his own taste, and in s,, far as it is good, the result will prove successful. The prepared paper is sensitised in a bath composed a* follows:—'Potassium bichromate, loz.: potassium fcrrrryanide. I*2o grains; water, lfloz.; methylated cspirit. ;>oz.; and anvmonia, 10 minims The paper, after having been drained of the surplus solution, is bung up to dry in the dark, as in the case of carbon tiss-ue. The paper should not be kept long before use after being sen_tised. but some workers say that it may safely be kept for si week or longer, if protected from changes of temperature. Printing, if the frame is placed in a good light, will be fairly rapid. In .slimmer an average negative will bc fully printed in from three 'o four minutes. After removal from the frame, the 'bichromate is first washed out of the paper in cob] water. and then the print is placed in verv hot water, at SO or 00 degree*, so as lo bring the picture into relief. It is not possible to say exact Iv how hot tbe water will have to be for any particular print, but experience will soon teach tho worker to adjust the temperature in his needs. Next comes the crux of the whole process, namely, the pigmenting. You will be able to get pigments specially adapted to this process from vour dealer. To begin with, it is unwise to go in for a large variety of colours. Either engraving black or sepia are colours which suit a large variety of subject*. It is necessary to have one or two hogs' hair brushes for applying the pigment, and I here, again, there is a special kind made with edges- so as to adimit of an even application of the pigment. Two brushes are the minimum, -because you -roust have a big 'brush, though not too hig a one. for applying the oil colour, and a fairly tine one for use as a retoucher afterwards. Do not make the great mistake of applvjng too much pigment at first. You will require some turpentine to thin your colour with when it is too thick. When pigmenting is over, and you have got something at any rale resem-bling the result at which you were aiming, the print is finished off by being dipped again into cold wafer and then pirnjed flat to drv naturally. On no account allow it to dry otherwise, or it: will roll up and probahly be ruined. There are a variety of means of adding to the. control of an oil pigment print, such, for instance, as the use of more than one colour on the =ame print, but these are refinements which do not. commend themselves to the beginner, but are best left to the practised expert-