I'd assumed it was due to the 3-step process (taking 3 photos quickly with red, green, and blue filters). Rather than have it all together on one colour film wh

I'd assumed it was due to the 3-step process (taking 3 photos quickly with red, green, and blue filters). Rather than have it all together on one colour film which was still quite new. It's interesting you can see the effect this has on moving water, where it has an oil-slick rainbow sheen.