Field Notes Journal a personal natural history of place

0.2 Regulation of Illumination

Aim

To learn correct control of illumination using mirror and condenser.

Specimen & Apparatus

• Prepared slide (any specimen)
• Compound microscope with sub-stage condenser and mirror

Method

1. Place the slide on the stage and focus under low power.
2. Adjust the mirror to obtain a bright, even field of illumination.
3. Raise and lower the condenser to observe changes in contrast and clarity.
4. Observe the specimen under varying levels of illumination intensity.
5. Repeat under higher magnification.

Observations to Make

• Effect of condenser height on image contrast and detail.
• Differences between strong and subdued illumination.
• Conditions under which structural detail is most clearly seen.
• Any visual artefacts introduced by excessive or insufficient light.