Scribing (cartography)
Encyclopedia
Scribing was used to produce lines for cartographic map compilations before the use of computer based geographic information system
s. Lines produced by manual scribing are sharp, clear and even.
An impression of the corrected compilation sheet is photographed onto scribe sheet material or drawn using pencil. While working over a light table
, lines on the scribe sheet are traced with a metal or sapphire-tipped scribe tool to remove thin lines of translucent coating to produce a handmade negative
image. This compares with drafting
where an ink image is made on tracing paper by depositing ink using a pen to produce a positive
image. Scribing produces a result superior to drafting, but is more time consuming.
The scribe sheet is made of a stable plastic base material and coated with a material which is designed for easy removal using a scribing tool to produce a cleanly cut line. Various colours are used, and orange is said to produce the least eye-strain for the cartographer.
One scribe sheet is produced for each map colour. Corrections can be made by "duffing" (re-coating) the scribe sheet with special duffing liquid. The detail can then be re-scribed. Printing plates are produced from the finished scribe sheets, one for each colour of the map.
. A stylus of required thickness is set in the trolley and the surface material is removed by applying light pressure as the trolley is moved over the image. Care must be taken to ensure the base material is not gouged or distorted.
Either a round point or chisel point stylus may be used. Chisel points must be set at right angles to the direction of movement. As well as single line gravers, double and triple lines can be produced with double and triple graver stylus. Small circles can be produced using motorised versions of scribing tools, and symbols, figures etc., can be produced using plastic or metal templates.
A stipple pattern can be used to produce an area symbol over the peeled surface. A stipple sheet with a simple repeating symbol (such as that for swamp or sand) is combined with the area by photographing the stipple onto the peelcoat.
Geographic Information System
A geographic information system, geographical information science, or geospatial information studies is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data...
s. Lines produced by manual scribing are sharp, clear and even.
An impression of the corrected compilation sheet is photographed onto scribe sheet material or drawn using pencil. While working over a light table
Light table
A light table is a viewing device that is used to review photographic film or artwork placed on top of it. It provides even illumination of the subject from below through a translucent cover and fluorescent lights that emit little heat. They can also be found mounted on the walls of hospitals and...
, lines on the scribe sheet are traced with a metal or sapphire-tipped scribe tool to remove thin lines of translucent coating to produce a handmade negative
Negative (photography)
In photography, a negative may refer to three different things, although they are all related.-A negative:Film for 35 mm cameras comes in long narrow strips of chemical-coated plastic or cellulose acetate. As each image is captured by the camera onto the film strip, the film strip advances so that...
image. This compares with drafting
Technical drawing
Technical drawing, also known as drafting or draughting, is the act and discipline of composing plans that visually communicate how something functions or has to be constructed.Drafting is the language of industry....
where an ink image is made on tracing paper by depositing ink using a pen to produce a positive
Positive (photography)
A positive is a film or paper record of a scene that represents the color and luminance of objects in that scene with the same colors and luminances . Color transparencies are an example of positive photography: the range of colors presented in the medium is limited by the tonal range of the...
image. Scribing produces a result superior to drafting, but is more time consuming.
The scribe sheet is made of a stable plastic base material and coated with a material which is designed for easy removal using a scribing tool to produce a cleanly cut line. Various colours are used, and orange is said to produce the least eye-strain for the cartographer.
One scribe sheet is produced for each map colour. Corrections can be made by "duffing" (re-coating) the scribe sheet with special duffing liquid. The detail can then be re-scribed. Printing plates are produced from the finished scribe sheets, one for each colour of the map.
Scribe tools
A tripod or trolley arrangement is used to hold the scribe stylusStylus
A stylus is a writing utensil, or a small tool for some other form of marking or shaping, for example in pottery. The word is also used for a computer accessory . It usually refers to a narrow elongated staff, similar to a modern ballpoint pen. Many styli are heavily curved to be held more easily...
. A stylus of required thickness is set in the trolley and the surface material is removed by applying light pressure as the trolley is moved over the image. Care must be taken to ensure the base material is not gouged or distorted.
Either a round point or chisel point stylus may be used. Chisel points must be set at right angles to the direction of movement. As well as single line gravers, double and triple lines can be produced with double and triple graver stylus. Small circles can be produced using motorised versions of scribing tools, and symbols, figures etc., can be produced using plastic or metal templates.
Area symbols
‘Peelcoat’ is used to produce a negative of an area of detail such as a lake or forest. The border of the area is cut or scribed on the peelcoat and the coat of the sheet within the area is peeled off to produce a negative image.A stipple pattern can be used to produce an area symbol over the peeled surface. A stipple sheet with a simple repeating symbol (such as that for swamp or sand) is combined with the area by photographing the stipple onto the peelcoat.