Re: F-Stop timer kit available

"Dennis O'Connor" <[EMAIL PROTECTED]> wrote

> It does variable time, or variable f?
> I enlarge at one f stop only and the
> variable is time...

Yup, that's what it's for.

Rather than setting the time in seconds you set the time
in stops.

The display shows time as 0.0 to 9.75 stops.
Stops are related to the exposure time as
follows:

 0.00 stops ==   1.0 seconds
 1.00            2.0
 ...
 4.00           16.0
 4.25           19.0
 4.50           22.6
 4.75           26.9
 ...
 9.75 stops == 861.1 seconds

or, time = 2^[stops display] seconds

To make the print one zone darker you increase
the time by one stop -- in paper zones, that
is.  Naturally, the stops/zone will change 
with the paper contrast grade.

--
Nicholas O. Lindan, Cleveland, Ohio [EMAIL PROTECTED]
Consulting Engineer:  Electronics; Informatics; Photonics.