There are 10 probes to measure skin sebum, elasticity, moisture, TEWL, pH, Melanin,erythema, friction, tone, gloss and time for shockwave propagation through skin. It ensures that we analyze products accurately to achieve effective function with scientific methods.
With the Colorimeter CL 400 a probe has been developed especially for the needs of measuring changes in the skin colour (e.g. for cosmetic and pharmaceutical efficacy tests or when exposing skin to a solar simulator, etc.)
Determining the Skin Surface Sebum
The Sebumeter is the most widely acknowledged, very accurate and successful sebum measurement device for skin, hair and scalp. Its use in dermatology and cosmetology is very well documented over many years with a large number of publications.
The measurement of the pH-value covers an important characteristic of any aqueous solution:
its acidity or alkalinity.
This value is determined by the concentration of hydrogen ions (H , protons) and hydroxide ions (OH ).
Physical basis for the measurement is the Diffusion law discovered by Adolf Fick in 1855.
dm dp=-D.A. dt /dx
where: A = surface in m2
m = water transported (in g)
t = time (h)
D = diffusion constant (=0.0877 g/m.h.mm Hg)
p = vapor pressure of the atmosphere (mm Hg)
x = distance from skin surface to point of measurement (m)
To access the smoothness of the skin, a disk is rotated by a small motor. Measured is the force the motor has to overcome to rotate the disk on a surface.
The smoother the material the less force the motor will need to rotate.
The achieved results are shown on as indices on the screen.
The measuring principle is based on a resonance running time measurement. Two needle sensors are placed on the skin. One is transmitting an acoustical shockwave, the other is the receiver. The shockwave propagates through the skin differently according to moisture and elasticity. The time the wave needs to go from transmitter to recipient is the measured parameter.
To meet the requirements for a precise determination of the skin color which is only based on (C) a few features, the Mexameter MX 18 specifically measures the content of melanin and only haemoglobin (erythema) in the skin.
These two components are largely responsible for the skin color.
The measurement is based on the absorption principle. The special probe of the Mexameter MX 18 emits light of three defined wavelengths. A receiver measures the light reflected by the skin. The positions of emitter and receiver guarantee that only diffuse and scattered light is measured. As the quantity of emitted light is defined, the quantity of light absorbed by the skin can be calculated.
The probe measures reflection. The gloss of a surface can be expressed by direct reflection of light send to this surface.
In the probe head parallel white light (see green arrow) is sent in a 60 degree angle to the skin surface (see as black line). Part of the light is directly reflected in the same angle (see blue arrow, angle of incidence = angle of reflection) and part of the light is absorbed by the surface and then scattered and reflected (see red arrows).
The Skin-Glossymeter GL 200 measures both the portion of directly reflected light, mirrored from the surface, which is related to the gloss and the scattered portion from the surface.
The measurement of the skin moisture is based on the internationally recognized (R) Corneometer -method, a capacitance method. This measurement is based on the completely different dielectric constant of water (81) and other substances (mostly < 7).