Grooving/ Tinting Flashcards
What are the 3 main steps to grooving a polycarbonate lens?
1)Groove the lens dry.
2)Leave only a little depth ungrooved.
3)Last pass = groove the lens wet so it looks less frosted and more polished.
How is dye prepared?2
-Clean tank of leftover residue
-use distilled or deionized water.
What 2 things make up the lens layout process?
Spotting and Centration
What are the two ways glass can be hardened?
Heat tempering
Chemical tempering
What is heat tempering/hardening?
Lens go in kiln for 2 to 3 minutes then get removed and cooled rapidly with forced air.
What is chemical tempering?
Sumbersed in salt, smaller ions are replaced with larger ones on the surface. Crowds the lens surface which squeezes the surface tension.
How do you start a new batch of dye? 5 steps
1) fill tank half full and bring to 140 oF
2)shake bottle well
3)pour dye into the tank
4)pour water into the bottle, shake, pour rest into tank x3
5)fill the tank with distilled water
What 3 things determine the life span of the dye?
-How long the dye has been mixed with water.
-How hot has the dye temperature been.
-How many lenses have been tinted.
What is a lens groover? 2
-machine used to cut into the edge of a lens
-most common method
What is a solid tint? 2
-same color all over the lens
-same light tranmission
What is a gradient tint? 3
-Vary in transmisson over the surface
-typically top to bottom
-fashion tint
what is a double gradient tint style?
lenses created with one color on the top, and another on the bottom which fade into one another
What is a triple gradient?
1 gradient in the upper half, a 2nd reverse gradient in the lower half and a 3rd color in the center.
What is UV dyeing?
Process of applying a treatment to a lens to acheive a certain level of UV protection.
What can sunglasses do that are sufficiently dark?
May reduce the transmission of visible light
What does a UV tint do for the eye? 2
-Makes the eye more comfrtable on bright days
-preserves the eye’s ability to fully and rapidly adapt to the dark at night.
What are the 3 ways we can tint a lens?
1- add a color substance into lens material before it becomes a lens
2-vacuum coating the color onto the surface of the lens
3-immersing the lens in a liquid dye so dye is absorbed
If a tint is spotty/ has circle like variations what is the problem?
the lens is cured unevenly
why are the colours off when dying a lens? 2
-Minerals or contaminations are in the dye water
-Someone keeps using hard tap water, and not distilled water
why does the lens appear blotchy after dying? 2
-The lens was not properly cleaned
-The lens cured unevenly during manufacturing
Why should a lens be dyed after edging?
so it dyes the edges as well makes it more cosmetically appealing.
How is tint removed with neutralizer?
tint is removed by placing them in solution of lens neutralizer-bleaching some tints
why should you not replace one tint at a time?
will be incredible hard to get it to match
how would you balance lens color on a lens?
add one of the 3 primary colors to help shift the color
what is the purpose of a light box?
compare the colors of lenses
what happens to a tint when it is exposed to sunlight and fluorescent light?
continually exposure can lighten tint after 12-18 months.
if kept in a drawer tint can last 5 years.
What is lens curing?3
-process of lens going from liquid to solid
-hard lens is cured slowly=lattice structure=longer to dye
-more open lattice structure=slower to dye
What temperature should you dye at?
-dye the best when at the reccommened temp for that dye.
How is lens tranmission measured? 2
-visually looking at them
-photometer measure light transmisson and UV in percent.
What is the minimum edge thickness needed for grooving?
2.3mm
