What the beginner ought not to do is to use his muscles. Oil printing is distinctly not an athletic pastime, and a man who plays the violin well, and has a supple wrist and independent fingers, will learn the trick of inking ten times faster than one who makes exclusive use of his biceps. Yet without going so far I have seen delicate young ladies bang away at an innocent oil print in such a manner that the ink was literally crushed over certain parts and entirely removed from others, with such disastrous irregularity that I was unable to recognise if the pictures in question were over, under, or correctly printed. One of these ill-treated oil prints I irreverently washed with automobile essence, soaked and inked anew, with entirely satisfactory results ! Which shows that given correct exposure, proper brushes and proper ink, an oil print may still refuse to develop if attacked in the wrong way.
Let the beginner exaggerate at first the delicacy of his touch, let him start with a brush lightly charged with No. 1 ink, well crushed and dabbed on a clean glass palette. If the ink does not take it may mean that the print is under-exposed, for both inks, or only for this particular ink, but before experimenting with a softer ink, let the beginner change his touch and give more length and insistence to the first half of the inking action (the downward movement). He may discover that there is nothing the matter with the exposure, and even less with the ink, and that it is his brush action that is to blame.
The most logical manner of acquiring reliable experience in the matter of exposure and its results versus inking, is to give three different exposures to three different portions of the same print. Divide your negative into three vertical bands by making two visible marks at equal distances on the glass side. Mask the two first bands and expose the third for half a degree Artigue, mask the first and the third and expose the middle band for one degree and a half, cover up both exposed bands, and expose the last for three degrees. Then wash, soak and ink. Such an experiment is worth pages of theory, and if the beginner is not sufficiently edified by the difference of behaviour between the first and the last band, let him double the exposure of the latter. If this does not teach him what effect variations of exposure can produce on subsequent inking, nothing else will.
SIGNS OF OVER AND UNDER-EXPOSURE. It must be understood that, by the terms over and under-exposure, I intend to convey the idea of a general excess or want of exposure, for, in one and the same picture, correctly exposed as a whole, certain parts will be over and others under-exposed for one and the same quality of ink. Example : a landscape negative taken on a bright day, will, if correctly printed for the foreground .and distance, show signs of under-printing for the sky, which will be obliged to be toned down to a monochrome value equal to that of a dark blue sky by using No. 2 ink, or even by adding to this already soft ink a drop or two of medium.
The signs of general over-exposure are lack of contrast, and consequently loss of detail and contour. All the planes will take the ink equally or nearly so, and the result will be flat, even with the harder ink, much more so with the softer. But nearly similar results will attend when a grossly under-exposed print is persistently dabbed with soft ink. It will become soiled all over without producing contrast. This particularity may deceive the beginner, but if there is any doubt on the question of exposure, let him try to wipe the ink off from the lighter half-tones with a wet hog's-hair brush or a wet pad of muslin. In the case of under-exposure, the ink will be removed at the first stroke, leaving the gelatine surface perfectly clean. With an over-exposed print it will take a deal of rubbing, and the surface will remain spotty. This is a useful test that never fails.
Of course, no definite instructions may be given on the subject of interpretation. The oil process confers the faculty of altering every value of the original picture ; that is quite understood. What has been made less clear is that the purely photographic values of most straight prints are not all wrong ; it is their relation to each other which is generally faulty, but in many cases only one or two portions of the picture will need darkening, or lightening to a certain extent, which must be the proper extent. Photographers will not learn when to correct, and especially when to stop correcting, by consulting text books, but by studying nature and the work of real artists in black and white. A year or two of constant study will make them realize that they still have much to learn in that quarter. I have been studying for years, and am still learning. I can do no more, as I have already said, than to describe as accurately as possible what I believe to be the surest way towards producing an obedient gelatine surface.