Plan Plotting And
    Contouring
 Requirements For Plan
    Production
 Scales
 Layout
 Plotting Methods
 Plotting Contours

Requirements for Plan Production

Drafting Media
Drawing Instruments
Lettering
Lettering Guide
Letraset
Other Pens & Instruments

Introduction

Drafting Media

One of the requirements for plan plotting is a surface on which to plot. The media available includes drafting film, tracing paper, cartridge and bond paper and linen, the most popular being the synthetic drawing films like 'Mylar'. Clay tablets and papyrus have not been used for some time, but were amongst the first portable surfaces on which maps could be drawn. Drafting films are translucent allowing copying by 'dyelining', they are stable so stretch of the plan is minimised and strong so that they can have detail erased without endangering the surface. They are also expensive when compared to paper based products.

The drawing media in use in Australia now conforms to either the International Standard A series or B series paper sizes. The cut dimensions of A series paper are shown below:

The paper sizes are obtained by halving the long side of the size before, and the sides are in the proportion of 1:2 (1:1.414).

Drawing Instruments - Pens and Pencils

There are basically two types of drawing instruments in use, the pencil (and its variations) and the ink pen. Generally the pencil is used for outline work while the ink pen is used for final drawing. Both require a high skill level to use effectively and both are capable of providing disastrous results if used carelessly.

Pencils must be kept sharp (and never sharpened over the drawing). Care must be taken when using other drawing instruments like set squares, if these instruments are dragged over the surface then pencil lines will smudge and the surface will become contaminated with graphite creating a very grubby plan.

Ink pens are capable of producing high quality linework but are often frustrating to use. Most pens in use today rely on the capillary action of fluid passing through a very fine hole to produce lines, and unfortunately the pens are prone to blockage. They must be used with other drawing instruments that have been designed for use with ink pens, otherwise there is a high risk of blurring the lines.

The fine nibs on the pens also have a habit of lifting fibres off the surface of paper surfaces, generally these pens give their best results when used on film surfaces.

The ink used in these pens is generally one of two kinds, either water based or solvent based. Some of the solvent based inks etch the surface of the drawing medium which results in a more permanent line (which is consequently harder to erase). If inkwork needs to be erased use solvent based erasers (often coloured yellow) which are designed to remove ink. These erasers will not remove pencil, use the softer pencil erasers.

Lettering

The secret to good hand lettering is practice, practice and more practice, but there are a few hints to ensure at least legible lettering. The most important is the use of guidelines.

Perhaps the example is an exaggeration but the use of guidelines will dramatically improve hand lettering; drafting officers of many years experience still use guidelines. The lettering must all be of the one size within sentences, and it must have a constant slope (either vertical or sloping). Following in these notes is a Rotring lettering practice sheet which shows the stroking used to form letters with capillary pens, and shows the correct proportioning of letters.

Lettering Guides

Stencil lettering guides are available for those who find the task of hand lettering daunting, and for larger titling fonts which are very difficult to execute by hand. These lettering guides come in a selection of sizes usually based on the I.S.O. standards, 0.25, 0.3, 0.5, 0.7 and 1.0 (mm). These guides can only be used with set pen sizes, and should not be used with smaller nibs. The ratio of line width of letters and letter height should be 1:10, so if 2.5mm lettering is required then a pen of 0.25mm line width is used. No other pen size should be used with a 2.5mm stencil guide. With larger stencils, say 7mm, it is easy to fit a 0.25mm pen into the slot, but it is probable that the letter will appear 'hollow' as the pen can wobble from side to side in the hole.

This may appear to be economical when it comes to purchasing pens but it creates very sloppy work and an untidy plan. Don't do it. The figure above shows the open stencil on the left, the correctly filled letter in the centre and the most likely result of using a smaller pen on the right.

Letraset

Self adhesive lettering is another option for lettering on plans, it is not cheap but gives an excellent appearance to annotations when done well. When used incorrectly it is as appealing as bad hand lettering. The carrier sheet is placed over the area to be lettered and the letters are removed by rubbing the letter onto the plan. Never use 'biro' pens to transfer the letters, use the correct tool or the cap off a pen so as not to leave ink or creases on the carrier film.

Other Pens and Instruments

Fibre tipped pens are never used for drawing plans of any importance, the ink is neither waterproof nor light-fast. 'Biro' type pens are not used either, they tend to leave blobs of ink at the start and end of lines.

'Liquid paper' type opaque correction fluids are also never used, in time the repair will dry out, crack and fall off the plan leaving the original incorrect detail visible, and the corrected detail on the floor.