Emulate Xtol replished with one-shot--why not?

[MattKing]

It's very simple in practice. Understand that the dial - the green part in Matt's photo - rotates with respect to the white page. You look up a development index in a table, such as 40 for Tri-X in D-76 1:1, or 33 for Panatomic-X in Polydol. Then set the "normal" arrow to the development index on the left, and read off time vs temperature on the right. If you don't know the development index but have a manufacturer's recommendation or a time for 68F/20C from the Massive Dev Chart or whatever, you can set that time+temp on the right and infer the development index, and read off different time/temp combinations.

There are some extra tables with numbers to add to the index to adjust time (basically, adjust contrast) for condenser / diffusion enlargers, paper grades, and so on, but I mostly use it for the time/temp adjustment.

reddesert has it correct.
When I make notes about development for a roll of film, I just note the EI I used, the developer I used, and the developer number I used.
Sometimes I even refer to the development number in a post here on Photrio.
Here is a scan off an older, 1970 version which shows the table of Development numbers and the related instructions. I didn't post this one earlier because it is more difficult to use the dial when working in degrees Celcius.

The "white-on-black" Dymo tape additions are from a previous owner, who is unknown to me. I like the fact that they may be 50 years old!
These older versions are slightly smaller overall, and it is therefore easier to scan two pages at once .