First go over the part to be coloured with the brush and clean water for the purpose of damping it. Next dry with clean blotting-paper to take off any superfluous water. Then take another brush with the colour, and beginning at the top, work from left to right and downwards. If it is necessary to recolour any part let the first coating dry before beginning.
Engineers have adopted certain colours to represent particular materials; these are given in the following table:—
Table showing Colours used to represent Different Materials.
| Material | Colour |
| Cast iron | Payne's grey or neutral tint. |
| Wrought iron | Prussian blue. |
| Steel | Purple (mixture of Prussian blue and crimson lake). |
| Brass | Gamboge with a little sienna or a very little red added. |
| Copper | A mixture of crimson lake and gamboge, the former colour predominating. |
| Lead | Light Indian ink with a very little indigo added. |
| Brickwork | Crimson lake and burnt sienna. |
| Firebrick | Yellow and Vandyke brown. |
| Greystones | Light sepia or pale Indian ink, with a little Prussian blue added. |
| Brown freestone | Mixture of pale Indian ink, burnt sienna, and carmine. |
| Soft woods | For ground work, pale tint of sienna. |
| Hard woods | For ground work, pale tint of sienna with a little red added. |
| For graining woods use darker tint with a greater proportion of red. |
Printing.—A good drawing should have its title printed, a plain style of letter being used for this purpose, such as the following:—
The following letters look well if they are well made, but they are much more difficult to draw.
For remarks on a drawing the following style is most suitable:—