Was shooting TMax ISO 400 today and put a yellow filter on my lens. Realizing that would darken my exposure -1 stop I decided to adjust ISO on my meter to compensate. I think of exposure in terms of left & right, i.e. going "right" from f8--f11--f16 etc. will darken, and going "right" 1/125---1/250---1/500 will also darken one stop each step. I think I goofed by thinking ISO 400---ISO 200---ISO 100 will lighten exposure. Actually I'm reducing sensitivity which darkens. I'm slightly dyslexic and I think I went the wrong way. What I did was thinking ISO 400 with a yellow filter is darkening exposure by one stop, so to compensate set ISO to ISO 200. I now think went the wrong way and am now TWO stops underexposed, i.e. effectively ISO 100 with no filter? That's beyond the one stop pull the Massive Dev Chart shows. SO, maybe if I develop for one stop push (ISO 200) I should at least get something I can decently scan?

Kent in SD