If the full frame was 18x24mm , do cinematographers take two shot per frame to cover entire 24x36mm or were they wasting film ?
Cine film travels (with exceptions like Vistavision) vertically as opposed to horizontaly like in still cameras no waste at all.
The release in the academy Frame 22x16mm was required because of the optical Soundtrack that requires a bit of space.
What was the logic for smaller frame ?
It's the biggest possible frame if the film travels vertically almost sprocket (right) to sprocket (left).
Is there any developer information for Citizen Kane or were they developing every scene roll differently ?
They most likely would have used Kodak D96, which has been the Standard MP B/W stock developer at the time and still is
If Gregg Toland used 24mm for 30mm diagonal of 24x18 frame , what is the lens equivalent in 35mm photography ?
Gregg Toland framed for Academy 22x16mm and not the 24x18 frame, he would have had the markings on the viewfinder or even a hard mask that would have blocked anything outside the Academy frame. The answer to your question is about 35mm (24x18mm Silent Ratio) or around 38 to 40mm (22x16mm Academy Ratio).
MDR , Was Toland using Cooke I or Cooke II series of lenses. In 1939 catalog , there was even a 15mm.
Cooke Speed Panchro series I the Series were only introduced much later (my mistake in my previous post), the 15mm was not a Speed panchro lens and most likely didn't cover the Academy or the Silent frame
By the way , If I buy 1939 Panchro 24mm lens , would it be able to cover only 24x24mm or bigger.
Maybe a bit more than 24mm but not by a lot. Plenty of cameras with 24x24 Format like the Robots for example the original Mount (BNC) is very very big though
If I change the distance of lens , does it help to cover 35mm frame but loosing the good thing ?
You would loose infinity Focus and the Quality would suffer a bit.
Do cinematographers still use small frame in film shots ?
Yes, most widescreen formats use an even smaller frame than that.
Was Toland taking and developing film as negative or positive ?
He shot B/W negative and the film was copied onto a printing/release stock again a negative to get a positive.