Garbo asked me: "What do I play in this scene?" Remember she is standing there for 150 feet of film – 90 feet of them in close-up. I said: "Have you … - Rouben Mamoulian

To accompany the transformations I wanted a completely unrealistic sound. First I tried rhythmic beats, like a heartbeat. We tried every sort of drum, but they all sounded like drums. Then I recorded my own heart beating, and it was perfect, marvellous. Then we recorded a gong, took off the actual impact noise, and reversed the reverberations. Finally we painted on the sound track; and I think that was the first time anyone had used synthetic sound like that, working from light to sound.

Colour cinematography tends to brighten and cheapen natural colour. The problem was to counteract that. I realised that colour in films is nearer to painting than to the stage. Now if you look, for instance, at a crimson cloak painted by El Greco, you’ll find that what first appears as a mass of colour is in fact a subtle blending of all sorts of shades, with patches of pink and blue and purple and green. So I treated the colour the way a painter would.

[Mamoulian] "[T]he majority of the films in the future will be done in color. Perhaps not immediately. Perhaps it will take three years or five years. But there must be progress and development in the cinema. Color will enrich it. It is part of that progress.