III. COLOURS ON TINTED PAPERS AND TINTED GROUNDS. Besides the kind of harmony already mentioned, there is another, which is produced by the contrast of light and dark shades of the _same_ colour. This might be employed in letter-press more frequently than it is at present, with some advantage, as the effects it is capable of yielding are very chaste and pleasing. In a photograph or an engraving, all the effect is dependent on difference of tones of one colour; and the beauty of a wood in summer consists chiefly in the contrast displayed by a variety of shades of green only. A deep green ink on a paper of a light tone of the same colour is especially good, if a heavy letter is used; and indeed in most printing in colours, full, solid-faced letter should be preferred to outlines or shaded ones, which are difficult to work, and have at best but an inferior appearance unless the darkest tones are employed. A deep blue on a light blue ground, or against a light blue border, is also good; and without the latter accompaniment it is not unpleasant on a blue wove writing-paper. To secure the proper effect, however, the tints should be of the same _hue_; that is, if the groundwork is of a bluish green, the colour that is to be worked upon it should also be a green inclining to blue; if, on the other hand, the ground is of a yellower green, the body of ink should also be yellower; and so on. This may easily be managed by adding a small portion of ink of the colour required, until the hue is matched. IV. NEUTRAL TINTS. In selecting borders for the more chaste description of printing, it is a pretty safe rule to avoid such as cover much surface, if they are to be worked in any strong colour or in black. When lighter tints are used, they will bear extension over a larger surface; and in this case a pale gray or neutral border will have a beneficial effect on any body with which it is contrasted, as well as on black itself, which is purified by its proximity. If the central printing is in black _only_, or in black and yellow, a _lavender_ gray may be substituted for the border. And in any case in which the central matter is all in one colour, it will improve it to have a border of gray which is _slightly tinged with the complementary of such colour_. Thus, if the body be red, a very small portion of _green_ may be added to the gray; and so forth. It must be remembered that in ornamental printing absolute cleanliness is indispensable. The same roller should never be used for different colours, even after it has been washed. Instead of hanging exposed to dust and to the air, rollers should be kept in a tightly-closed box; and in this manner they will remain a long time in good order. The tins of ink should be similarly preserved, and the lids never left off except at the moment of using from them. These are small matters; but it is only by patient attention to minute details that excellence can be attained in printing. OILING A PRESS.