What does a micron range describe?
A micron is a unit of length. A quoted range describes a target size interval, but it does not by itself explain the complete distribution of a sample. Ask what limits are used, how the material is measured and what proportion is permitted outside those limits.
A quick note on mesh. Mesh counts sieve openings per linear inch. Within the same sieve standard, a higher mesh number generally means a finer opening. Microns (µm) express size directly; an exact conversion requires the sieve standard and aperture specification.
Why does mesh need a standard?
Mesh is a sieve-related designation. Sieve construction and the applicable standard affect the relationship between a mesh label and an opening size. When comparing two suppliers, make the test method part of the comparison rather than relying only on the name.
What else changes the appearance?
Particle shape, lighting, moisture and the scale of a photograph influence what a material looks like. A close-up may make a fine sample appear coarse. Use photographs to understand appearance, then request an identified physical sample for evaluation.
How should samples be compared?
Use the same formulation base and processing conditions. Record the sample reference, loading and evaluation method. This makes differences easier to interpret and connects the selected sample to a future specification.
What belongs in your enquiry?
Include the preferred micron range or mesh designation, the sieve standard if known, your application and any acceptance limits. If the size is not yet decided, describe the intended texture and request comparison samples rather than guessing a final specification.