Final answer:
Encaustic paint is the type of paint using egg yolk that is not the medium for swiftness. It involves mixing wax with egg-based tempera to create paint and is known for its strong, resonant colors and extremely durable finish.
Step-by-step explanation:
The type of paint using egg yolk that is not "the medium for swiftness" is encaustic. Encaustic paint is a technique that involves mixing wax with egg-based tempera to create paint. It was used extensively in funerary mummy portraits from Fayum in Egypt. Encaustic paintings are known for their strong, resonant colors and extremely durable finish.