Prior Scientific PriorLab, Manual

Page: 8 / 15

8
Prior Scientific
9. Phase Contrast
Figure
2
Phase contrast is a technique used to amplify contrast in unstained samples. To be able to
see objects with phase contrast the optional phase kit is required. This includes a phase
turret condenser (see figure 2), phase objectives, a centering telescope and a green filter.
Firstly the standard condenser must be removed by loosening the retaining screw and the
phase turret condenser installed in its place. Swap the standard objectives (if you have
them) for phase contrast objectives, these are engraved PH, and select the correct condenser
position (0 for brightfield, 10 for the 10x objective, 20 for the 20x objective etc.) Follow
the steps in section 7 to ensure that Köhler illumination is set up properly. Remove an
eyepiece and insert the centering telescope, this allows you to focus on the phase rings and
make adjustments to their alignment. The two rings, one bright, one dark should overlap
perfectly (A), if not (B) then their position relative to one another should be adjusted using
the centration screws at the rear of the condenser (Figure 3).
To make adjustments to the phase ring alignment push in the adjustment screws and then
turn. When the alignment is complete remember to pull the screws back out or it will be
impossible to change condenser position.