Visual assessment of Coptic tapestry fragments, red monastery excavation, Upper Egypt

الملخص EN

This study presents visual measurements for dye fading of archaeological tapestry fragments dated to the 4^th century of Coptic period.

The objects were discovered at the red monastery of Anba Bishoi and Anba Bigo, Sohag, Upper Egypt.

They are suffered from many physical deterioration aspects, such as fading, weakness, dryness and staining.

So the need to estimate the rate of damage visually becomes argent.

The International Organization for Standardization (ISO) and Japanese Industrial Standards (JIS) introduced visual and instrumental color fastness evaluation methods.

Instrumental methods aren't preferable to be used in our study, because taking samples is not always acceptable.

So, the challenge for any conservator is how to visually measure the rates of dyes fading, which is happen, due to thermal and light degradation.

This paper deals with a physical method for determine the changes of the dyes colour in archaeological textiles by creating standard symbols, referred to different forms of the dyed textile fading.

As it was sufficient to represent the degree of fading of dyed textiles by arbitrary steps, which represent the change in shades of dyes and coded with symbols characterized the rate of fading in a simple way.

Furthermore, coding the direction of change is noted.

and the extent of change is estimated subjectively by adding numerical value and Chroma through munsell book of colour.

By all these visual estimation methods of morphological appearance, the conservator could document the state of damage safely.