Quote Originally Posted by RalphLambrecht View Post
Share your math with us.

Also, don't forget to adjust for reciprocity failure.
Uh oh. If you're asking for me to share my math, there must be something wrong with my multiplication (which is very likely).

I finished my exposure and brought my camera and notecard in. I have an aperture scale in one of my photo books that only goes to f/64. I extended that out to f/512, which is the first full stop past my aperture of f/381

I figured out the aperture of my camera by dividing the pinhole diameter by the focal length. My focal length is 7.5 inches, which multiplied by 2.54 to get 19.05 cm. i multiplied that by 10 to get 190.5mm. I divided that by 0.5, which is my pinhole diameter. That gave me an aperture of 381.

I rounded up to f/512 because I knew underexposure was a problem. I didnt adjust for reciprocity the first time because I was like "well, let's see what happens before I start adjusting times." The negative turned out to be more underexposed than I anticipated

My second negative is ready to be developed, so I'll see how that one looks before reporting back here