Page 241 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
So, after all these losses, how much fluence is left to heat up the hair?
Table 47 shows that the loss of light energy can be very significant by the time it reaches the hair. It also shows the differences between different filters and skin colours.
These losses must be taken into account when treating hair in different skin colours.
Wavelength range (up to 1200nm)
ST1
ST6
400nm
67%
38%
500nm
56%
37%
600nm
45%
33%
700nm
36%
29%
Table 47 – The amount of light energy which can heat up the hair follicles
20 J/cm2 of IPL light using a 700nm filter in a very dark-skinned person is quite different to 20 J/cm2 with a 600nm filter in a pale-skinned person! In fact, the above table shows that only 5.8 J/cm2 will reach the hair in the dark-skinned person, while 9 J/cm2 will reach the hair in the pale- skinned person.
Figure 129 – IPL filter for hair removal in light skin
________________________________________________________________________ 241 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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