Re: Step wedges

Keith Schreiber (StillPoint@worldnet.att.net)
Thu, 21 May 1998 11:16:08 -0700

Dwight,

I may be wrong about this, but I believe that "calibrated" merely means that
each step has been read with a densitometer and recorded for reference. If
you have a transmission densitometer and are going to be making your own
readings, you will be calibrating it yourself anyhow so buying a calibrated
step-tablet is unnecessary. The steps are theoretically 0.15 density units
apart, however they are rarely perfect. A calibrated step-tablet reveals the
imperfections, which are probably insignificant anyhow.

If you haven't yet read Judy's excellent article on the use of step-tablets
in alt-process printing, I recommend it.

If you want to get really technical, albeit in a very practical way, check
out Phil Davis' "Beyond the Zone System".

Keith

-----Original Message-----
From: Dwight Shackelford <tshack@silver-bayou.com>
To: alt-photo-list <alt-photo-process-L@sask.usask.ca>
Date: Wednesday, May 20, 1998 6:42 PM
Subject: Step wedges

>I remember some discussion here about a year ago about inexpensive step
>wedges. I'm looking at Bostick & Sullivan's page and the calibrated one
costs
>$19 (uncalibrated $8). Is there still a less expensive alternative
available?
>
>What is the practical difference between the two mentioned above? Could I
>produce something myself cheaper?
>
>Dwight
>
>