Fluke Biomedical 07-440 - Manual (Page 7)

Operation
General
2
2-1
Section 2
Operation
2.1 General
1. Select and position the proper aperture (small flat side UP) as outlined in Section 2-3, Set-Up.
2. Set the ZERO control as outlined in Section 2.3, Setup.
3. Place the film over the aperture with the emulsion side up.
4. Press down on the measurement arm as indicated (PRESS HERE) until firm contact is made with
the aperture.
5. Read the optical density on the digital display.
For high densities and/or small apertures, it may
take a second or two for the reading to reach
equilibrium.
DENSITY SUBTRACTION
The difference between two densities may be determined as follows:
1. Turn the ZERO control so that it reads zero (flashing minus sign) over the first (reference) film area.
2. Take a reading over a second film area.
3. The relative density, positive or negative, of the second area measured will be indicated on the
display.
Be sure to check the ZERO (Step 1) before making
subsequent readings. Although the zero drift is
small, a routine check prevents the possibility of an
Incorrect reading if, for example, the ZERO knob
has been accidentally disturbed.
NOTE
NOTE