Drawing sheet

Different qualities of drawing sheets are available in the market. Depending upon the nature of the drawing, the qualities of drawing papers are selected. The drawing paper should be of uniform thickness and of such quality that erasing should not have leave any impression on it. For ordinary pencil drawings, the paper selected should be tough and strong. It should be uniform in thickness and as white as possible. One of the sides of the drawing paper is usually rough and the other smooth. The smooth surface is the side for the drawing work. Good quality of paper with smooth surface should be selected for drawings which are to be inked and preserved for a long time. It should be such that the ink does not spread. These are of two types.

1) Hand-Made Paper

Hand-made papers have rough surfaces, pale in colour and not used for regular work, but meant for charts.

2) Mill-Made Paper

Mill-made papers are most commonly used for regular work, and are available in different sizes and rolls. They are specified by their weight in kg per ream or density in grams per square meter.

Designation of sheets

The drawing sheets are designated by symbols such as A0, A1, A2, A3, A4 and A5. A0 being the largest. Table 1 gives the length and breadth of the above sizes of sheets. For class work use of A2 size drawing sheet is preferred.While working or handling, the papers are liable to tear on the edges. So slightly large size (untrimmed) sheets are preferred. They are trimmed afterwards. IS: 10811:1983 give the designation of preferred trimmed and untrimmed sizes.

Table 1: Standard Sizes of Trimmed and Untrimmed Drawing Sheets

Sl. No.	Designation size in mm	Trimmed size in mm (Width x Length)	Untrimmed size in mm (Width x Length)
1	A0	841 x 1189	800 x 1230
2	A1	594 x 841	625 x 880
3	A2	420 x 594	450 x 625
4	A3	297 x 420	330 x 450
5	A4	210 x 297	240 x 330
6	A5	148 x 210	165 x 240

Fig. 1 Standard Size of Drawing Sheets 

Fig. 2 General Features of a Drawing Sheet

Basic Principles

Surface area of A0 size is one square meter. Successive format sizes (from A0 to A5) are obtained by halving along the length or doubling along the width. The areas of the two subsequent sizes are in the ratio 1:2. The basic principles involved in arriving at the sizes are:

(a) x:y = 1: √2

(b) xy =1

Where y and x are the sides and having a surface area of l m² so that x=0.841 m and. y =l.l89 m.

Fig. 3 Relationship between Two Sides

Quality Drawing Paper

The drawing papers should have sufficient teeth or grain to take the pencil lines and withstand repeated erasing. A backing paper is to be placed on the drawing board before fixing drawing/tracing paper, to get uniform lines. Before starting the drawing, the layout should be drawn. White drawing papers which do not become yellow on exposure to atmosphere are used for finished drawings, maps, charts and drawings for photographic reproductions. For pencil layouts and working drawings, cream colour papers are best suited.