Page 329 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed

308 Maritime Archaeology: A Technical Handbook, Second Edition
axis of symmetry. This may be a problem with a wall shard where it is difficult to determine its symmetry, whereas a rim or base fragment will be simple.
An alternative method of measuring the diameter is to make a series of stiff, plastic arcs of inside and outside curvatures, with fixed and known diameter. Again, care is required to ensure that the plane of curvature of the measuring device is perpendicular to the axis of symmetry of the pot (Figures 11.9a and 10). Another helpful item is a plastic sheet with con- centric circles drawn on it, so that base and rim diameters can be measured from fragments.
V. DRAWING TECHNIQUES
In making an artifact drawing, it is usual to start the drawing in pencil. Light construction lines can be drawn onto the plan and the main outline and important features can be drawn in. It is essential to keep the pencil lines as light as possible because they will eventually have to be rubbed out. It is best to postpone the inking until the drawing is complete and one is satisfied that the drawing is correct. This is important because it is much easier to erase pencil lines than ink lines.
Before starting ink work, it is worth recalling some important rules that have already been mentioned: (1) prepare the drafting film surface using inking powder or some other agent to clean the surface of grease and dirt; (2) keep hands as clean as possible, and preferably work resting on a tissue so that the surface does not pick up grease from one’s hands; (3) when using a ruler, ensure that the shoulders of the pen are not clogged, otherwise the ink will run under the ruler; and (4) to help the ink dry quickly, so that there will be less danger of smudging, a hair dryer can be used to artificially speed the drying process. However, inked lines should not be worked on with a rubber until the ink has completely dried which usually takes 24 hours.
One very effective solution to the problem of erasing pencil construc- tion lines on inked work is to do the pencil work on one side of double- matte film and to do the inked work on the reverse side. In this way, there is less chance of the eraser damaging the inked work.
A. ERASING INK LINES ON FILM
There are two options when a mistake has been made: leave it to dry or deal with it right away. Both options have advantages and disadvantages. Generally speaking, small smudges or blots that require cosmetic work, or