Digital Photography of Documents

Digital cameras are ideal for copying documents, especially faded manuscripts. The conventional techniques that we apply to our ground-based and kite aerial archaeological photographs are equally applicable to documents.

Working outside the visible spectrum (Ultra-violet / infra-red) is made more easy, as filters are not needed to block visible light, if the document is lit only by the light of interest. Care should always be taken and appropriate eye protection worn when using UV.

Professional systems are much more refined but the modern digital camera and (often free) photographic software make basic aspects of these techniques available to everyone.

1422 Conveyance to John Bompas by John Tuttebury, son and heir of Henry Tuttebury

Original colour

Colour removed

Red Channel and colour then removed

Blue channel then colour removed

Although the differences between the above images is minimal, with some documents, they can be quite pronounced, especially if the document is multi-coloured. There are other very effective software based techniques. Such approaches can minimise the need for potentially harmful methodologies, using say, ultra-violet light ,as pointed out by others.

However, there are few problems nowadays with recording UV images, especially if work is limited to UV-A (320-400 nm).

Fuji S5600 camera converted for full spectrum use plus B+W 403 filter. Illumination: Hand-held 41 UV LED flashlight in normal room lighting (400 ISO, f3.2, 1/4sec.)

Shorter wavelengths can be used to control the growth of moulds and other micro-organisms but they can also cause fading of the image / text and damage the substrate.