G T Clark
gtclark at festival.ed.ac.uk
Mon Mar 21 08:23:38 EST 1994
septate at tamsun.tamu.edu (Richard E. Clopton) writes:
>Niccy Scholfield (Scholfield at bchm.unp.ac.za) wrote:
>: We were wondering just exactly how tattoos work. Unlike a protein dye that
>: comes off when the skin sloughs off, a tattoo is guaranteed for 99 years!
> The dyes/pigments are engulfed by macrophages.
> I suppose my question is--> why do tattoos fade over time? Do the
> pigments break down over time, or do the colored pigments kill
> their macrophages faster than the balck/green dyes? Don't know.
The main reasons for the fading are, as far as I know, that :
1) The macrophages die, and not all of the dye is taken up by the next
one that comes along (hence the slight spreading and blurring over
2) They tend to be in the light a lot, so the pigments get bleached.
There are, I'm told, pigments on the market that are alleged to be more
stable than those that have been around, but they've only been around
for a few years, so it's not entirely clear how much so under real
circumstances. The only real safeguard would be to keep it under cover
when in bright sunlight.
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