Tank commando, WARNING = its not about tanks, M41

[Vertigo]

Very confusing film that i can only find referenced here back in 2009. I have seen it in TV listings recently.
The Warning is because its not a tank film. Its about underwater divers so i suppose its a reference to the air tanks.
What confused me though is - Its a 2nd WW film, its in Black and White. OK so far. In various shots there are M41 bulldogs on both sides. What ! How do you get bulldogs in an early war film? Checked the date and its made in 1959. So why is it in black and white??
Anyhow I put it here, also because its got Bulldogs in, which despite their abundance after the war don't seem to appear in many films.

[jarndice]

The Film "The Longest Day" was made in 1962 and many people have asked why it was shot in Black & White especially considering the star studded cast,
The reason is simply technology's inability to keep up with Film Makers ambitions and cost!
The Black and White format allowed the interleafing of "Stock" Footage into the film with no obvious difference between live and acted action.
The later arrival of "Colorizing" came too late and to this day still looks wrong,
It should also be noted that the producer of the film was so strapped for cash making the film he took out a second mortgage on his house to get it completed so the additional cost of colour film stock was out of the question.
Another example is the Film "The Cruel Sea" again made in black and white, it helped that the backgrounds were almost always various shades of grey indeed as many as 50 shades of that colour, again stock shots were easily laced in with no sign of the join.
This practice has continued to this day especially with made for television films.