Which gloss meter can test samples of curved surfaces?

A gloss meter is an instrument for testing the surface gloss of a sample. A general gloss meter can be used for flat products such as paper, wood boards, and tiles, but it cannot be used for some small objects such as water cups, screws, and water pipes, or objects with curved surfaces.

All standard gloss meters are of flat design. If used on a curved surface, the measuring beam will reflect off the instrument Detector causing incorrect readings. The more curved the surface, the greater the error. The solution to this problem is to use a small area. The light is scattered slightly by the surface, but as long as the reflected beam remains narrow enough to stay in the instrument Detector, the reading will be correct, which is where microporous Glossmeters are required to measure these particular products.

This article sorts out some small hole gloss meters that can measure curved surfaces.