Various Types of Reflective Beads (click to shop)
Reflective glass beads come in different types and sizes. Bead size is measured in microns or mesh size. A 50 mesh bead (297 microns) for example would be used for making traffic paint reflective. The larger beads sit up higher in the paint and reflect at sharper angles. Large beads come in several types with standard AASHTO beads being the most common, and FAA spec airport beads being the most specialized and the brightest. Traffic or paint beads are distributed on top of wet paint rendering it retro reflective. Traffic beads are why you can see road lines at night.
For applications such as reflective paint, reflective tape, or reflective garment trim, small beads are used. These are normally 300 mesh and above in size. Note that the higher the mesh size, the smaller the bead. And the lower the micron size the small the bead. Small beads are often referred to as reflective powder because of their powder like consistency. Because they are small, they mix in with a liquid clear base and stay in solution longer than larger beads would. They also work better for making reflective tapes. Reflective powder beads are why you can see road workers and road signs at night.
In summary, larger reflective beads are generally used on highway lines to make them brighter at night. They are dropped onto wet paint. Small microscopic beads or reflective powder beads are used for making reflective fabric, reflective tape, and reflective paint.