Mirka Microfinishing film (MI231 / Polarstar SR)

Film

The maker publishes these figures. A single value per grade, no distribution given, so each is drawn as a point.

Each grade below shows its size in microns, its spread (the published distribution, where a maker or standard gives one; most makers publish none), and where that size lands on the reference scale, a shared yardstick for reading grit numbers across makers.

Particle sizemicrons, log

5030201053

coarserfiner

inkmeasured or standardmaker figureour estimate

shapeknown distributionpoint, spread unknown

MI231 60 micronMaker-published

Mirka

60 µm

Maker micron (~P220).

spread not published · reference scale about #230

MI231 40 micronOur estimate

Mirka

40 µm

~P360; retailer-summarized, not yet confirmed on the official title (C-confidence).

spread not published · reference scale about #320

MI231 30 micronOur estimate

Mirka

30 µm

~P500; retailer-summarized (C-confidence).

spread not published · reference scale about #400

MI231 20 micronOur estimate

Mirka

20 µm

~P800; retailer-summarized (C-confidence).

spread not published · reference scale about #600

MI231 15 micronOur estimate

Mirka

15 µm

~P1200; retailer-summarized (C-confidence).

spread not published · reference scale about #760

MI231 9 micronMaker-published

Mirka

9 µm

Maker micron (~P2500).

spread not published · reference scale about #1300

Polarstar SR 7 micronMaker-published

Mirka

7 µm

Maker micron (~P2500).

spread not published · reference scale about #1850

Polarstar SR 5 micronMaker-published

Mirka

5 µm

Maker micron (~3000-grit class).

spread not published · reference scale about #2500

Polarstar SR 3 micronMaker-published

Mirka

3 µm

Maker micron (~5000-grit class), past the FEPA-P range.

spread not published · reference scale about #4000