Frans spied on his rivals to learn their techniques. He also burglarised their residences to steal drafts and ideas. One of them cought him in the act and was beaten for his trouble. Yet Ridderkerk still had trouble producing original art. When he heard about Hendrick Rammp, a great painter of still life art, Frans went after him. He threatened Hendrick with bodily harm if the old man failed to teach him his secrets.
He agreed to sit for a portrait by Rammp. He found the old man's secret ... to his doom. Rammp was a sorcered. He transferred his subjects into his paintings. They were lifelike because thery were once alive. Ridderkerk became just another subject, trapped in a painting.
Ridderkerk was a poor painter but a highly skilled and agile burglar. He used various furniture as weapons to knock out people.