How did the master artist contribute to the completion of paintings in Bikaner's studios?

By putting finishing touches occasionally (gudarayi)

Answer: By putting finishing touches occasionally (gudarayi)
The master artist in Bikaner's studios would occasionally put finishing touches to the paintings, a process referred to as "gudarayi."

A prevailing practice in Bikaner was to set up studios called Mandi, where a group of artists worked under the supervision of a master artist. From inscriptions, it can be gathered that Ruknuddin, Ibrahim and Nathu managed some of these professional studios. Several Mandis existed in Anup Singh’s reign. On the completion of a painting, the court archivist entered the name of the master artist and the date behind the painting. This practice resulted in the name of the master artist being inscribed on works of his pupils, who may not be painting in the same style as the master. However, it becomes evident from these entries that the master artist would occasionally put finishing touches to the paintings. The term used for this was gudarayi, literally meaning to ‘lift’. Apart from its activities of making new miniatures, the studio was entrusted with the task of marammat or repairing and making nakals (copies) of older works.