Using the ruler took 30 seconds. Used no chemicals, paper or electricity.
Add 15 seconds if you don't have an f-stop timer and need to use a chart.
Saves yer money - saves yer time - takes yer choice.
A note on using Darkroom Automation's stops<->seconds chart: If you are only applying a stops correction to a time you can simply multiply your present exposure time by the number in the chart.
As an example:
- your present exposure is 5 seconds and you want to add 1.4 stops
- look up 1.4 stops in the chart and find 2.6
- multiply 5 seconds by 2.6 => 13 seconds is the new time