Drawing materials include draughting film on polyester base, Indian ink, copying machines and plotters used in drawing preparation.
Important properties are:
- that the mechanical stability of the draughting film does not change with time
- that the adhesion between the film base and the drawing layer is good
- that the adhesion between the recording and the drawing layer is good
- that the recording has good light and water fastness
- that layers of drawings do not adhere and no recording is transferred to the next drawing
The permanence and the durability are tested in accordance with the Swedish National Archives regulations. Materials and machines may be certified in accordance with the Swedish National Archives regulations, se link to the right "Certification of archival materials". SP is the only Swedish accredited certification body.