Grayscale setting for B&W movies?

[Yo]

With a b&w still photograph, if one scans it grayscale, and saves it grayscale, it has a much smaller file size than if one scans and saves it as a color photograph. (Although the colors aren't there, only grey scales, if saved as a color photo it takes up a lot more space, I guess looking for those 24 million colors, rather than 256 gray scales.)

What about when encoding a B&W film? Would saving it grayscale save a lot of file size?

If so, is there any way to do that in AutoGK? Other programs?

[len0x]

No, usually greyscale movies are more difficult to compress due to not having sharp color edges, but rather blury and noisy half-tones.