A method for dyeing and/or retanning of leather objects includes providing a leather object. The leather object has been processed by at least a tanning process. The leather object is introduced into a process chamber. The leather object is subjected in the process chamber to a pressurized fluid. The pressure of the pressurized fluid is controlled to reach a supercritical state. The leather object is subjected to a dyeing agent and/or a retanning agent, which dyeing or retanning agent is dissolved and/or transported in the pressurized fluid for at least a predefined period of time while the pressurized fluid is in the supercritical state. The pressure is reduced in the process chamber. The leather object is removed from the process chamber. The pressure reduction is controlled over time.