How to Use a Loupe

A loupe is a small magnifier used to examine closely held objects in greater detail. More compact than a magnifying glass, it is commonly used by jewelers to examine gemstones and pieces of jewelry, but also by dentists to examine teeth for hairline cracks and botanists to identify distinguishing plant characteristics. Most loupes are hand-held, but some are built into specialized spectacles; these instructions are for the hand-held version.

Difficulty: Moderately Easy

Instructions

Choosing a Loupe

1. Pick a triplet loupe, which has three lenses arranged to prevent distortion and color problems, over a single loupe, which has only one lens.

2. Look for a loupe with black framing around the lens. The black eliminates reflections that can distort the apparent color of the object you are viewing.

3. Select at least a 10-power loupe for examining jewelry, while a two-power or five-power loupe is sufficient for dental work. The greater the magnification, the closer you hold an object to the loupe to get the best focus (shorter focal length), the smaller the area you can see with the loupe (narrower field of view) and the less you can move the loupe to keep the object in focus (smaller depth of field).

4. Consider getting a loupe with a built-in light source.

Using the Loupe

5. Hold the loupe up to your eye, close but not touching. If you have difficulty keeping your hands steady, you may want to arrange them in a sort of tripod by bracing your wrists together against your face.

6. Place the object to be examined in front of the loupe. Gemstones should be held with wooden tweezers to prevent them from being contaminated by the oils from your fingers. Other small objects, such as leaves, may also be held with tweezers to prevent them from touching your hands.

7. Look through the loupe's lenses.

8. Note any unusual properties of the object when seen through the loupe.

Resources

• Buy a jeweler's loupe from Widget Supply.
• Buy an illuminated loupe from Optics Planet.