What were portrait masks for the mummies made out of?
they were made of plaster.
This site lists 6 or 8 different materials for portrait masks for mummies. Perhaps one of the most common was cartonnage.
Check this site for more details.
http://touregypt.net/featurestories/masks.htm
The portrait masks for mummies in ancient Egypt were typically made out of a material called cartonnage. Cartonnage is a type of material made from layers of linen or papyrus, which were glued together and then molded into shape with a plaster-like substance. The surface of the cartonnage mask was then painted with vibrant colors to create a lifelike portrait of the deceased person.
To find this information, you can often start by conducting a search on the internet using reliable sources such as museum websites, academic articles, or books. By searching for keywords such as "Egyptian mummy portrait masks" or "materials used in ancient Egyptian burial," you can find references that provide detailed explanations and descriptions of the materials used in creating these masks. Additionally, you may also come across multiple sources that can provide further insights and details on the subject.