Figure 10-26.–Densitometer with both transmission and reflection
capabilities.
Figure 10-25.–Step tablets.
daylight balanced xenon flashtube. It can also produce
exposure times from 1/100 to 1/10,000 second.
Step Tablets
A sensitometer is set up to make only one exposure.
In order to provide a range of exposures, a step tablet is
placed between the light source and the light-sensitive
material. The step tablet is a strip of neutral-density
filters in equal increments, ranging from 0.05 to 3.05.
This range provides a 10 f/stop range. The most common
step tablets are as follows (fig. 10-25):
1. 21-step tablet-1/2 f/stop between each
increment.
2. 11-step tablet-1 full f/stop between each
increment.
Courtesy of X-Rite, Inc.
302.339X
Control Strips
A sensitometric control strip should be processed as
a minimum-at the beginning of a production day (or
shift), before any production is processed, and before
shutdown. You should process a control strip just before
an important mission, or a special-interest film is
processed.
To expose and process a control strip, you should
take the following steps:
1. Take the film (in a lighttight container) and place
2. Turn on the sensitometer and allow it to warm
3. Turn off the room lights.
4. Place the film emulsion-side down on the
5. When hand processing or using a rotary tube
6. When a roller transport processor is used, check
7. Stick the film into the processor so the lightly
it next to the sensitometer.
up for a minimum of 15 seconds.
sensitometer and lower the platen to make your
exposure.
type of processor, load the control strip on the
reel. When machine processing, replace the film
in a lighttight container. Turn on the room lights
and turn off the sensitometer.
the speed, temperatures, and the proper
operation of all systems.
exposed end of the film enters the machine first.
When hand processing or using a rotary tube
type of processor, process normally.
10-40
