View attachment 182840 Printed out Richards 3 -part Dial-Calculator and compared the values with my lightmeter Gossen Variosix F.
Its very clear that the EVs/Light Values on the big wheel are 5 STEPS OFF.
10 should be 5 up to 15 instead of 20. then 16,17,18,19,20 should be added by setting minutes as m. not min due to lack of space. Light Value must also be moved.
maybe someone could contact Richard.
Here are multiple versions incl. Ilfords
https://www.thingiverse.com/thing:147404
first link not working, maybe revivable via archive.org
i am using this one:
http://www.rahji.com/pdf/koolish.pdf
Link inside this one found at archive.org
http://www.rahji.com/wordpress/2007/05/12/pinhole-exposure-times/
http://web.archive.org/web/20090221195707/http://ca.geocities.com/penate@rogers.com/diameter.htm