This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol1", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
This chapter would not be complete without a few words on laying washes of colour. It is scarcely necessary to say that the first step must be to carefully clean up the drawing with indiarubber so as to remove all pencil marks, and if necessary to rub the drawing over carefully with bread crumbs. Care must be taken with these, however, as the bread crumbs, if scrubbed in unmercifully, are almost as effective as ink-eraser, and can easily spoil the inking in of a drawing. If any doubt whatever exists as to the waterproof qualities of the ink, it is best to wash over the whole drawing with clean water and a large brush, drying off the water immediately on clean blotting paper. By this means the ink which would run is dissolved, and soaked up immediately into the blotting paper, leaving the drawing perfectly clean and ready for colouring. When applying large washes of flat colour it is best to elevate the top of the board so that the colour will flow more freely down to the bottom. The tint should be mixed in excess rather than too little, and care should be taken to see that the tint is very light. One is apt to misjudge the effect of a large body of the same colour from a small sample tried on a scrap of paper, for what in the sample appears to be right will often prove to be too dark when laid on in a wash. The mixed-up colour in the palette or saucer should be stirred round every time the brush requires more colour, otherwise, as many of the colours are heavy, the particles will collect in the bottom of the saucer and the tint be rendered uneven. Especially is this necessary where reds or browns and blues are mixed, for the specific gravities of two colours are so different that the particles separate, and the colour changes in tint unless frequently mixed up. The largest brush full of colour must be employed for large washes, and be carried right across the top of the space to be coloured, and continued downward in successive horizontal strokes across and across until the bottom of the drawing is reached: the principal point to bear in mind being that the brush must always be quite full of colour. Should any of the lines be inadvertently overstepped the colour may be pushed back with the finger, and the mistake rectified. When the whole space is covered with the wash, dry the brush and use it to soak off the colour, which will remain in a little pool all along the bottom of the drawing, until there is no excess of colour left. To the beginner this apparently drastic use of a veritable sea of colour is somewhat alarming, but it is the only means by which an even wash can be obtained, and with care and practice no mishap should occur, while the largest surface can be covered with a tint so flat that it might be mistaken for the actual colour of the paper.
It is advisable in all cases, especially with drawings which may have become a little greasy, and it is absolutely necessary on cloth and paper tracings, to mix a little "ox-gall" into the colour, as this ensures the colour lying evenly. Care should be exercised not to employ too much, as ox-gall is liable to dirty the tints, particularly light washes of yellow ochre and light red.
Very frequently it happens that portions of the drawing have been scratched out with a knife and renewed. All these spots should be carefully noted mentally before the washes are applied, as the colour will soak into them more and leave a darker tint. This can be avoided by sopping up the extra colour with a small pad of clean blotting paper, and the spot should be continually "dubbed" till the tint has begun to dry and the particular portion ceases to darken. When thick colours are required to be used for a long time, such as dark Venetian red for walls in section (the colouring of which may take a couple of hours on a large plan), care must be taken to keep the colour from drying in the saucer. In order to keep the tint of about the same thickness, in warm weather particularly, a drop of water should be mixed into the saucer every second or third time the brush is refilled with colour.
The illustrations accompanying this chapter are prepared as actual working drawings, the only difference being (in the detail sheets) that the titles would not be carefully printed on but merely written in round hand. Otherwise they show clearly how working drawings (Plate I.) and detail drawings (Plate II.) ought to be, and generally are, prepared.
In making working drawing, clearness and accuracy are the chief points to aim at. In order to fulfil these requirements it is necessary to cultivate a precise and clean style of draughtsmanship, and a few words on the care of the instruments may not be out of place, as if the instruments on the board are kept clean and tidy the chances are in favour of the drawing being in the same condition.
On coming to the office in the morning, before removing the covering sheet from the board, dust it well, and after it has been taken off, dust the board, and any loose articles on it. Then, before beginning to use the T-square and angles, rub them well on a piece of rough drawing or blotting paper. This removes the pencil grit, which rapidly accumulates on them, through passing over old lines; and the operation should be repeated occasionally during the day.
Then open the instrument box and take out the instruments required, afterwards putting the box in the drawer, as if it be left on the drawing board it either becomes full of indiarubber shreds or eventually gets knocked off the board altogether by the T-square, an operation calculated neither to improve the temper of the draughtsman nor the quality of the instruments. The Indian ink, also, if being used, should not be kept on the board, for ultimately it is certain to be upset.
The modern Indian ink bottle is usually supplied with a cork having a quill in it for filling drawing pens. This looks very useful, but it is usually cut so blunt that it is difficult to fill the pen cleanly, and besides this, it does not reach to the bottom of the bottle unless the cork is jammed quite home, which makes it a two-handed matter to fill the pen. Consequently it is generally preferable to cut the quill off and use an ordinary pen for filling the drawing pens with. It is advisable to keep the bottle closed as much as possible, as the modern ink dries very quickly, and soon thickens if exposed to the air.
The drawing pens should not be filled very full, as this usually results in blots, which takes longer to remove than it does to refill the pen; likewise, a penful should not be used up to the bitter end, as this will spoil the quality of the line.
If the pen is to be laid aside for a few minutes, the ink should be first removed by drawing a piece of cloth or folded blotting paper between the nibs, and if it is a hinged pen, it should be opened occasionally and given a thorough cleaning. Ultimately the nibs of a drawing pen become worn at one side, as the pen is always used in the same direction, and it begins to give a line of shaky quality. This can be put right by very carefully sharpening the pen on an oil stone, rubbing down each nib separately from the outside first, and then bringing them together and carefully rubbing the points together - and then testing with ink and trying again until the desired line is obtained without cutting the paper; but perhaps it is safer to send it to an instrument maker to be "set."
Now that needle points are so generally used and so easily replaced, the only instrument that needs looking after in this respect is the divider, which is usually supplied without needle points; and as this is probably used more than any other, it is well to sharpen the points occasionally, as visible holes in a drawing are unsightly and take the ink badly when that stage of the work is arrived at.