EYE ON EQUIPMENT

Tint Lab Know-How

Expanding your scope of service is easy—even with a small tint lab—by implementing these tricks of the trade

Your patients can view their world through whatever color lens they want. Image courtesy of BPI

if you are already doing your own edging in house, a logical expansion of the finishing lab is the tinting lab. It will allow your creativity to flow and customer service to soar.

As we discussed in the last Eye on Equipment, a small amount of space, some tint tanks (a four- to six-tank unit is suggested for start-ups), and accessories like thermometers, tint trays, and lens holders/dipping arms, is all you need to get started. What comes next is trial runs to understand your equipment, and some tricks of the trade to help you master your technique. To get the most out of this equipment, the experts at BPI have supplied some tips and techniques for getting flawless tints.

SETTING STANDARDS

Determine for yourself a standard of color and absorption for each tint color you use. For instance, determine the optimum shade of gray, brown, black, etc., you think will be most desirable for patients. Use a sample lens with a freshly mixed batch of tint and execute the ideal tinting procedure as laid out in your equipment instructions.

After it is rinsed and dried, keep the lens next to the tinting equipment, and use it to compare against future tint jobs—tinted for the same amount of time and using the same procedure. When the new tint jobs fail to match the standard lens, it’s time to change the tint in the tank.

TROUBLESHOOTING

Even when you’ve become proficient at tinting, some irregularities in the tint may occur.

COLOR VARIATIONS. Are you using tap water to mix the tints? That could be the culprit, as the mineral content can cause color deviations and chlorine can affect the red side of the spectrum and compromise the grays and browns. Try distilled or deionized water. If using tap water, let it sit out overnight to allow chlorine to dissipate and sediment to settle.

The existence of even a small amount of heat transfer fluid in the tanks (from accidental dripping/splashing) can also affect color performance. Rinse tanks under running water for five to 10 minutes to be sure.

PITS AND BUBBLES. Small imperfections in the lens surface may be caused by co-polymerizations with oil on the surface of the mold, or a splatter of solvent. They are usually invisible, but may become noticeable after absorbing tint neutralizer, water, or lens prep solution. Avoid repeated neutralizing at high temperatures, and let lenses cool slowly and without water. When cooled, wash in water and wipe dry with a non-abrasive, lint-free cloth.

STREAKS. Streaks are usually a “clumping together of tint pigment,” most likely a result of a separation of the pigment from the water in the tank. Streaks happen when a tint solution hasn’t been used in a while, or is used less often than others. Periodically heating and stirring tints when they are not active will help keep them properly suspended.

GETTING FANCY

Gradient tints can add a lot of style to the lens. The top portion of the lens is tinted darker than the bottom, but the percentage of tint in each portion is completely up to you and the patient. The most common ways of gradient tinting is through a mechanical arm attached to the tint tank. The arm dips the lens into the solution at varying depths and lengths of time, all determined by the operator. The same is done for double-gradient tints.

The tint arm will hesitate before cycling to the next “step” of the gradient process, and that will sometimes result in a line of demarcation rather than a gradual fade. You may be coloring with too hot a tint solution, or need to adjust the “L” rod (which holds the lens holder) by a few millimeters to alter the “steps” on the lens. Or, you can dip the entire lens into the tint for a few seconds at the end.

But don’t limit yourself to horizontal gradients. Once you’ve perfected your gradient method, try diagonal or a vertical tint on the temporal edge for truly dramatic looks. It can add zest to any lens, especially rimless styles that you’ve edged into a custom, eye-popping shape.

— Susan Tarrant

Color Correction Made Easy

IF A GRAY LENS IS…

Too blue Dip in orange or brown

Too green Dip in blue or red

Too purple Dip in yellow

Too brown Dip in blue

IF A BROWN LENS IS…

Too yellow Dip in blue

Too blue Dip in yellow or brown

Too gray Dip in orange or red-yellow

IF A GREEN LENS IS…

Too yellow Dip in blue

Too blue Dip in yellow or brown

Too gray Dip in blue and yellow

Source: Practical Systems, Inc.

Automated systems like this one from BPI make gradient tints easy