How Lenses Are Made - Part 6
Lens Tinting
Once the lenses are edged to fit the frame, they move to our tinting station. Tinting is where we add filters and colors that customize both function and style.
The Tinting Process
Tinting works a lot like dyeing fabric - or even coloring Easter eggs. Here’s how it’s done:
- A dye (powder or liquid) is mixed into hot water, brought close to a boil.
- The lens is dipped into the solution and left to soak for a specific amount of time.
- The tintable hard coat we applied earlier absorbs most of the dye, while the lens material itself absorbs some as well.
- By adjusting the time in the dye bath, we can control the density and light transmission of the tint.
Throughout the process, we use a light transmission device to measure and confirm the exact shade and performance.
Matching the Perfect Color
To ensure accuracy, Chadwick keeps a library of hundreds of controlled tint samples. These samples never fade, allowing us to compare every lens against a precise standard.
Each tint also follows a spectrograph curve, which shows exactly how much light at different wavelengths is filtered out. We check every lens to make sure its curve matches what the doctor prescribed.
Simple Tints vs. Complex Colors
- Simple tints (like blue or yellow): Created with a single dye, dipped, and ready in minutes.
- Complex tints (like a rich No. 8 green): Require carefully balanced mixtures of multiple dyes such as yellow, green and others, layered to achieve the perfect vibrancy.
Testing in Real Light
Once tinted, every lens is double-checked not only with instruments but also against different light sources:
- Bright outdoor sunlight
- Indoor fluorescent lighting
- Other common environments
This ensures that the lenses look consistent and natural, no matter where they're worn.
Ready for the Next Step
With tinting complete, your lenses move on to the anti-reflective coating process (AR), which we’ll cover in the next stage.
