Pfaff's work uses encaustic and a variety of papers. The artist is originally from London and received her BFA from Washington University (St. Louis) and an MFA from Yale. She is best known for her installation pieces but she has also worked with prints where she has used things like vegetation and maps (etcetera). I assume these pieces are from this part of her work. She has also worked creating sets for theater productions.
Grigoriadis uses oil and acrylic on linen in her two smaller pieces and oil on canvas in her larger pieces. She was also a founding member of A.I.R. Gallery--the first female art collective in the USA, founded in 1972. Her work is often brightly colored decorative patterns. She is part of the group of artists referred to as Pattern & Decorative artists.
Find out details on both artists at the gallery website link above.