Measuring Of Exposure Values; Measurement With Constant Exposure Time; Measurement With Constant Lens Aperture; Special Indications - JOBO Comparator 100 Mode D'emploi

4.

Measuring of exposure values

Place an unknown negative or slide in the
enlarger, focus, and select the picture details to
be printed. The Comparator is placed on the
baseboard or easel so that for selective mea-
suring the lightest part of the negative or slide
which still shows some details is projected onto
the measuring cell . For full integration mea-
surement, swing in the diffuser disc. Turn the
Comparator on with switch
sure value can be determined in two ways:
4.1 Measurement with constant exposure
time
For this method the time determined in making
your ideal print is set with the time scale
aperture of the enlarging lens is now changed
until the balancing lights are adjusted to dis-
play the green LED only.
You may now expose the paper for the time indi-
cated, set in the procedure above.
4.2 Measurement with constant lens aper-
ture
For this measuring method the enlarging lens is
set to the desired aperture, and the time scale
is turned until the balancing lights
only the green LED burning. The exposure time
thus found is transferred to the timer and the
exposure is made. If the unit cannot be adjusted
by turning the time scale , select a different
lens operture.
13
5.

Special Indications

1. TIME SCALE
light when unit is turned on.
2. LEFT RED LED lights up
and no adjustment will
change it.
3. RIGHT RED LED lights up
and no adjustment will
change it.
, and the expo-
6. Mounting of the diffuser for full area
(Integrated) Measurings
Remove existing red filter from the mounting,
place it on the diffuser, mark and cut out and
place diffuser in the mount instead of the red fil-
ter.
. The
7.

Maintenance and care

The Comparator 100 does not need any speci-
al maintenance. However, the measuring win-
dow should be kept clean, because dust and
dirt on this spot can lead to incorrect measuring
results. The measuring window is easiest clea-
ned with a cotton ball or Q-tip. When not in use,
the instrument should be stored in a cool and
dry place. Just like any other precision measu-
ring instrument, the Comparator, too, must be
protected from excessive heat, humidity as well
have
as from shocks and impacts.
8.

Dimensions

Width:
Length:
Height:
does not Battery exhausted
Too much light
Too little light
76mm
140mm
26mm
14