Change of lens colour after DIPCOAT

**Claudia** · 07-30-2008, 09:18 PM

Need some advices here.

After the UV400 treatment, the lens be tinted slightly yellow. However, after the DIPCOAT process - the lenses will totally change into greenish yellow colour . Does anyone know the cause of this problem?

**Didier** · 07-31-2008, 03:45 PM

Lacque may have a bit of blue to hide the yellowich. Maybe this blue is too much and mix with the yellow shift a bit this yellow to the yellow/green.
But dipping uv or other can give and heat all this mixture after can sometime give very strange result.

Most of the time, when we have a tint or UV, I prefer to spin the lens and tint the spincoat after.

**Websta** · 07-31-2008, 05:42 PM

If your UV is very yellow it may mean the UV needs changing. Most of the UV we use is clear, and when we start getting yellow, it means the tint is "off"

Try changing the tint bath and see what happens.

**Claudia** · 08-01-2008, 03:44 AM

Thanks for all your kind advice.

Have convey the information to my lab manager , we are in the process of changing the dip coat material to a better one. Hope it helps. Thanks again!

**Chris Ryser** · 08-19-2008, 04:56 AM

Originally Posted by Websta

If your UV is very yellow it may mean the UV needs changing. Most of the UV we use is clear, and when we start getting yellow, it means the tint is "off"

Clear UV will not protect up to 400 nm. Yellowish UV will, and if you dont like it tint it over, read following article.

http://optochemicals.com/optochemica...sm_article.htm