Quote Originally Posted by Stephen Benskin View Post
...no timer used for printing is consistent and repeatable enough...
If you do all your testing at the same time with an electronic timer there shouldn't be any problem. Any motor driven analog timer won't be adequate.

With a good timer that pays attention to the niceties of timing AC power you can use any time you like - within the reciprocity limits of the film. If you use Kodak, Ilford or Fuji film then reciprocity isn't much of a problem. With FSU film you can run into reciprocity at 1 second, and testing should be done with a shutter controlling the exposure.

Step tablet testing with an enlarger does need an enlarger with very even light output and a Sola AC line regulating transformer.

Quote Originally Posted by Stephen Benskin View Post
... Most people don’t have a meter accurate enough to measure the light from an enlarger for sensitometric purposes.....
Such an easily corrected problem ...