Jacoba, or Coba, was born in 1876 as the daughter of the book printer Coenraad Ritsema and his wife Jeanette (Jannetje) Moulijn in an artistic family with one sister and two brothers.

[4] She was in her education a pupil of August Allebé, George Hendrik Breitner, Carel Lodewijk Dake, Fredrik Theodorus Grabijn, Jacob Ritsema (her brother), Thérèse Schwartze, and Nicolaas van der Waay.

She focused herself on the still life style, and was rejected by several famous artists she had in mind as tutor - they thought they insecure Ritsema didn't need their guidance.

[4] She became a teacher of the students Grada Jacoba Wilhelmina Boks, Lize Duyvis, Jan den Hengst [nl], Tine Honig, Coba Surie, Hillegonga Henriëtte Tellekamp, Victoire Wirix, and Gonda Wulfse.

[5] While focusing on still lifes and portraits, Ritsema's works were described in 1947 by critic Johan van Eikeren as if they could have been produced by a man - something that was considered to be a compliment in those years.