Page 151 - Blog Posts v1

Table 2: Order of effectiveness of lasers on coloured inks
I have colour-coded the results to make them easier to interpret.
Clearly, for all colours, the picosecond lasers work more efficiently than their nanosecond counterparts (top row). However, interestingly, the 532 nanosecond output appears to be very useful in treating red, orange, yellow, green and blue inks (row 2) - although, not so good at black!
The picosecond lasers then come in strongly in row 3 for all colours.
But, perhaps most interesting, is that the alexandrite laser (755 nm) appears to be poor for all colours, except green and blue, when compared with the other systems (including the nanosecond laser).
Conclusion
These are very interesting results. I think they show that picosecond lasers are 'generally' better at inducing ink removal than nanosecond lasers. But, the 532 nanosecond output appears to do very well for most colours - except black!
I have two comments on this study:
1. The range of fluences is quite large, from 0.8 to 3.4 J/cm2. It would have been better if they had used the same fluence across the study;
2. I think they should have left a longer period following the treatment. Anecdotal evidence indicates that there is more clearance around six to eight weeks post- treatment.
Mike’s Blog Posts 151