Anthotypes are images made with plant pigments.
One makes an extract of plant material. Common solvents are iso-propanol (rubbing alcohol), ethanol (cheap vodka) or boiling water. Paper is then coated with the extract and allowed to dry.
These pigments are relatively sensitive to fading in bright sun. Thus one can make an image by placing opaque objects or a positive transparency on the paper and exposing it to bright sunlight. Exposures are long, measured in hour or days.
The resulting prints are often fugitive, as they will continue to slowly fade on further exposure to light. That is part of the fun!
I generally use two types of plant material to make anthotypes. Most commonly, I use the spice turmeric which results in red-brown images. More rarely, I use paprika which give nice orange images that are very unstable.