Hola! Happy 1 millionth day of quarantine.
I used to have yellow/green filters on my 35mm lenses. So I have a bunch of 49/52mm filters. Kinda hard to find yellow/green somewhere. Instead of finding filters to use for my Pentax 67, I figure I get the square ones so I can use them with my LF lenses as well.

I'm assuming I can stack a yellow and a green filter to make a "yellow/green" filter yes? It seems kinda obvious but hey, all this alone time is making me lose arguments with myself.

Also, what would be the approximate filter factor for that? Same as a yellow/green or add the yellow and add the green square filter together?

See, I'm losing an argument with myself already!