Image and sound interferences which are due to erroneous signals.

Unwanted visible effects in the picture created by errors in the video processing or noise/interference in analog circuits. Common artefacts include 'edge crawl' or 'hanging dots' in analog pictures or 'blockiness', noise or 'contouring' in digital pictures.

Items found on shipwrecks.

A term used to describe the distortions added to the original signal during the coding and decoding processes.

"Objects, not being records, retained because of their informational value or because of their relationship with the records or archives." (KA, p.464)