What is meant by the film type letters?

[divewizard]

I recently bought some old Hoya and Toshiba filters. In the boxes there are filter use tables.



The Hoya table for black and white refers to type B & type C films. Do you know what the letters stand for?

On the table for Hoya color filters it refers to types A, B, D. & F color films. What do these letters refer to?

The Toshiba table does not refer to different letter types of balck and white film but refers to color film types A, B. & F.

 

[divewizard]

The back of the old Hoya filter containers also has a condensed table

 

[Freakscene]

It refers to colour balance - below is an incomplete list.
Type A film - color film balanced to artificial light sources at a color temperature of 3400K.
Type B film - color film balanced to artificial light sources at a color temperature of 3200K.
Type D film - obsolete term for film balanced for daylight.

Marty

 

[divewizard]

Is there any way to know when these filters were made by the printed inserts in the boxes?

 

[Spavinaw]

If you go to the FOR COLOR FILM chart and look at the line for Type F film you will see in the column under CLEARFLASH that it says NO FILTER. Obviously Type F film was balanced for clear flashbulbs. It was balanced for a 3800K light source; however, not all flashbulbs burned at 3800K.