The performance of the Pen Hardness Test is extremely simple. The tension of the estimated or known spring is set with the aid of the cursor. Holding the instrument in vertical position and placing his point on the test surface drawing a line along from 5 to 10 mm at a speed of about 10 mm/sec. The stylus should produce a scratch that is barely visible to the naked eye. If the spring pressure is too high, the scratch is clearly visible; if too low, there is not scratch.

The applied pressure, fixed by blocking the slider, is marked in Newton. The springs can be adjusted with different loads, in order to cover different force ranges, from 0 to 3 N, from 0 to 10 N, from 0 to 20 N and from 0 to 40N. To start the test, adjust the spring pressure, in the position in which it is expected that there is no scratching and lock into place. Perform the test and subsequently examining the deformed area with the goal to identify cracks on the coating and/or deformation of the material surface.

If there are no obvious damage, repeat the process in succession, working with larger loads as long as you observe cracks or deformation visible on the material surface. Unless otherwise agreed, inspect the coating after 30s to the naked eye to detect the marking. The damage can be assessed more easily after you have cleaned all the debris left by the use of the pen on the paint surface with a soft cloth or a cotton swab or an inert solvent. If this is done, make sure that the solvent does not affect the coating in hardness testing. By agreement between the parties, a microscope (magnification x6 to x10) can be used to assess the damage.

When you use a microscope, this must be indicated in the test report. If there was no marking, repeat the test with no overlap of the test areas, with the scale of hardness to the verification marking.

The test is carried out by evaluating the mark left on the surface by a pen with a tip loaded with a constant pressure. The pressure on the tip can be changed by changing the spring. A visual tract on the surface after the hardness test indicates a negative outcome of the resistance to scratches.


Material typeStandardTest method
screeds EN 13813 EN 13892-6
self-levelings EN 13813 EN 13892-6
grouting mortars EN 13888
gypsum-based grouting EN 13963
paints/varnishes -
surface protection mortars EN 1504-2


Instruments used to perform the test: Pen hardness tester


The test consists to determine the surface hardness of the materials using the pen hardness tester.The test consists to determine the surface hardness of the materials using the pen hardness tester.