The technique involves rubbing the wet paint film in a circular motion with a gloved forefinger and observing the result. If the problem is one of flocculation, the color in the rubbed area will be the correct one. The rubbing action dispersed the pigment in the paint.

The grind gauge is an instrument that indicates the fineness of grind or the presence of coarse particles and agglomeration in a dispersion. It is commonly used to determine how finely ground the particles of pigment are dispersed in a sample of paint. The gauge is then viewed at a 20-30 degree angle.

The fineness of grind is reported in both units. Each grind gage comes with a specially designed stainless steel scraper as seen below each gage. The sample to be tested is placed across the channels in the stainless steel block on the deep end of the track (0 on the Hegman scale and 100 µm on the micron scale).

It is commonly used to determine how finely ground the particles of pigment (or other solid) dispersed in a sample of paint (or other liquid) are. This is important because many types of solid materials must be ground into finer particles in order to be dispersed in liquids.

A grindometer is a device used to measure the particle size of suspensions, typically inks such as those used in printing, or paints. The suspension to be tested is poured into the deep end of the groove, and scraped towards the shallow end with a flat metal scraper.

Grinding Earth to Make Pigment Using a mortar and pestle, pulverize your sample into sand-sized particles and then grind them into smaller particles. For pieces larger than gravel, you may have to break them up with a hammer.

The most widely used surfactants for pigment dispersion in coating formulations are: Fatty acid derivatives. Phosphate esters. Sodium polyacrylates / polyacrylic acid.

Process:

1. Mix 2 Tbsp. casein powder with 5 oz. warm water, and let sit overnight.
2. Discard the water that accumulates on the surface.
3. Mix 1 Tbsp. borax with 4 oz.
4. Mix a spoonful of the casein mix with pigment in a glass bowl or on your palette.
5. Paint on wood, paper, or canvas. Add water if you want a watercolor effect.

Pigment grinding is the essential step that allows powdered pigments to be transformed into smooth, liquid paint. The process is in itself an art form that receives little attention, even in the world of artists’ supplies.

The liquid sample is poured into the deep end of the Channel or Groove and is distributed with the Scraper Blade towards the flat or shallow end of the Channel carved into the Grindometer until the largest particle size present in the sample liquid is equivalent to the depth of the groove of the Fineness of Grind Gauge.

The Hegman scale or National Standard scale (“NS”) presented on this precision Grindometer and Fineness of Grind Gauge shows a range from 0 to 8 NS with numbers increasing as the particle size decreases. 0 Hegman = 100 microns particle size 4 Hegman = 50 microns particle size 8 Hegman = 0 microns particle size

This precision instrument is used to determine particle size and the fineness of grind of particles in printing inks. The NPIRI gauge and its scraper are made of hardened stainless steel and the gauge has two grooves with a gentle slope. The groove width is 25mm (0.98″) and the groove length is 165mm (6.5″).

Graduated in microns, mils, NS (Hegman) or PCU (North), the gauges have a tolerance of ±2µm (0.08mil). The groove width for all models is 12mm (0.47″) with a groove length of 127mm (5.0″). Elcometer 2020: The standard gauge shows graduations in microns or mils, NS and PCU which are all engraved on the top of the gauge.