Objective & Immersion Oil Care
Protect the Scope. One Drop Does It.
A quick reference for anyone using oil-immersion objectives on lab microscopes.
One small drop is all it takes. More oil doesn't improve the image — it just increases haze, cleanup time, and the risk of oil creeping into the objective housing. The most common way an oil-immersion objective gets damaged isn't age, it's how much oil someone reaches for.
Here's what actually belongs on the slide, and what to do the moment you're done looking.
Do this
- Use Type A or Type B immersion oil only — whatever your lab has standardized on, never a substitute.
- Apply one small drop directly on the slide or objective tip, not both.
- Focus, then adjust. Bring the sample into focus before adding any more oil, if needed at all.
- Wipe the objective immediately after use — every time, no exceptions, even for "just a quick look."
- Use lens tissue only. Fold fresh tissue for each wipe so you're not redistributing debris.
Avoid this
- Multiple drops "to be safe." Excess oil pools, spreads to nearby components, and attracts dust.
- Reusing old, dried oil. Dried residue scatters light and is harder to remove without solvent.
- Paper towels, tissues, or cloth. These scratch the coating — lens tissue is the only safe material.
- Leaving oil on overnight. A quick wipe before you walk away prevents a service call later.
- Switching objectives with oil still wet. Wipe first, always, to avoid oil migrating onto dry objectives.
The habit, every time
STEP 1
One drop on the slide
STEP 2
Focus, image, done
STEP 3
Wipe with lens tissue
STEP 4
Cap or cover the scope
Every kit we build for your bench includes fresh lens tissue — the only safe material for this step, every time.