Panchromatic film and plates.

When did panchromatic film and plates first become generally available? How quickly did they replace orthochromatic materials materials for general purpose photography? We’re they more expensive?

1890s
Not quickly
Yes, at first. Think diff between cost of cheap b&w vs slide film.

A few points of refernce. I ahve two editions of Kodak's "The Photography of Colored Objects". 1926 and 1938. In 1926 they showed spcectra for "regular film" (blue sensitive), orthochromatic, and panchromatic. In 1938, they showed regular film, orthochromatic, and type A, B (orthopanchromatic) and C (hyperpnachromatic) films. The panchromatic in 1926 looks like the type A in 1938.

Verichrome was a very common and widely used film. It was orthochromatic . In 1956 they replaced Verichrome with Verichrome Pan.

I am pretty sure regular (blue sensitive) film was available commonly through at least the 1930s in roll film, maybe even into the 1940s. It was cheaper than ortho or panchromatic films.