# Optical Forums > Ophthalmic Optics >  Tinting ?

## Kevin Howtopat

when tinting a dark gradient lens on a gradient machine, is there a way to avoid the semi circular effect at the bottom of the lenses? As it is I'm bleaching out the bottoms (sometimes unsuccessfully) Very annoying

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## uncut

I think that a shorter stroke on the lift arm, and ensuring the lens holder swings very freely on it's axis is a possible cure for your issue. 

 You can try finishing the color by hand dipping for ultimate control.

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## Kevin Howtopat

I'll give it a whirl, Thanks!

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## Kevin Howtopat

Found out the semi circles i was getting are cause by bubbles that form between the lens and the lens holder. Wonder if adding salt to my tints would help? Any thought?

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## uncut

Some lens holders are notorious for bubble creation.  Try a different one. 

 Stirring, or agitation creates bubbles, too.........avoid doing this during the cycle, or immediately prior.   

Stealth paddling only!   You might want to try a product called Hot Topper(if it is still made).

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## uncut

> Found out the semi circles i was getting are cause by bubbles that form between the lens and the lens holder. Wonder if adding salt to my tints would help? Any thought?


I would worry about salt attacking the steel tank(s).  Not a problem with glass containers, tho.

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## PRECISIONLAB

We use a small amount of dish soap in the rinse water to break the surface tension. Also consider setting gradient 3/4 with the last dip slightly submersing the entire lens to remove any bubbles formed on lens holder.

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## Kevin Howtopat

precisionlab Brilliant idea thanks

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## Kevin Howtopat

Uncut you're right didn't think of that

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## Chris Ryser

> *when tinting a dark gradient lens on a gradient machine, is there a way to avoid the semi circular effect at the bottom of the lenses? As it is I'm bleaching out the bottoms (sometimes unsuccessfully) Very annoying
> *



Try to tint the lens on your gradient arm, instead of removing the dye. Slower process that way but better results.

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## IWEARMAN

Is there anyone contemplating doing away with EyeMed?

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## mervinek

> Is there anyone contemplating doing away with EyeMed?


Yes!  Will be official in May!

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## ogfullmelt

i wish

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