I have a question regarding the ASA (ISO) ratings of today's films (B&W negative film) when used in conjunction with old exposure meters. I have a GE DW-68 serial No. R02119 which I've been using for a while now with decent results, I believe it's giving accurate readings. Tonight I read that back when my meter was built there was a safety factor of one stop built into the film ratings. I probably read that years ago and completely forgot about it.
So should I actually be setting the exposure index number to the next smaller number on my meter, e.g. to 50 when I'm using a film rated 100 ASA? Is there any adjustment I should make for color negative film or transparencies? (I haven't shot any slides since the 1980's, but I've been thinking about getting some again.) Also just to double check-the dial on my meter reads"EXPOS INDEX" on the outer ring, so those should be ASA numbers, not the older GE film numbers?