Well, I don't know.
I have two k-1000's. One is for Black & White, and the other color.
I just leave the red filter on the Black & White camera. I generally shoot in the daytime, and I generally use a Red filter. I like to travel light, so I just leave it on there. That's really the only reason.
Sorry if I double post this. I usually just leave the #25A filter on the camera. I have two; One for Color, which has no filter, and the other for Black & White.
I used a red filter because it was on the camera. I have two k-1000's that I usually keep with me. One of them is loaded with color, and the other is for Black & White. I generally shoot with a #25A filter, so I just leave it on the camera. I guess it's laziness really.
Ok, figured out why I couldn't post.
Now, I generally have one camera for color, and one for Black and White. I usually opt for a red filter, and thus just leave it in place all the time.
It's just laziness.