Eli Sinai designed more than 150 stage productions.  He designed both the scenery and costumes for the majority of these productions. It is only in  a small number of productions (about 35), that he shared his work with another costume designer. He reviewed hundreds of sketches, fabrics, wigs, shoes, and garments. 

The enclosed sketches are evidence of an approach that is practical, refined, clean and accurate. At times (A Dog’s Will) the costumes give a humoristic nod, an allusion or a dialog with other subjects. However, generally speaking, the costumes are very simple, free of any beautification. In some of them (Mother Courage and her Children or Anna Christie), one can observe a deep acquaintance with the types and history of the fabrics, the designs and colors, without overshadowing the nature of the character or the qualities of the actor. 

Sinai knew his actors well. With some of them he worked many times, and aided by the costumes he selected for them, he knew how to emphasize certain qualities or traits that were in line with the play or with the specific task. The costumes never imposed themselves, neither by their colors, nor by pretentious shape or exceptional material. They only complemented the overall stage vision, paying close attention to the text and to the actor. 

As Orna Ben Meir writes in the exhibition catalog: “Sinai, the former actor and model, can be recognized by the deep understanding he shows in the design of the characters, by the physical-material connection of the actor’s costume- a seamless blend that allows the actor to assume his stage persona. Sinai does not impose his own visual image on the actor. He forms and designs it from the actor’s body, while maintaining an understanding and close attention to the requirements of the play’s plot”.