The Importance of Optical Clarity

Optical Clarity: Why It’s Important and What it Means for You

Selecting the best auto-darkening welding helmet reaches beyond standard occupational safety issues; it also should take the wearer’s vision into account. Wearing the right helmet not only protects your face and eyes from sparks but also can contribute to your overall productivity and work quality. And, it all comes down to the helmet’s optical clarity, or how well you can see out of it.

We know that welding isn’t an easy process, especially for welders who wear a helmet for the better part of an eight- or 10-hour day, sometimes while working on thin, exotic and/or expensive materials. When you’re able to more clearly perceive subtle variations in the ever-changing arc and weld puddle, you’re able to deliver more accurate end results, with higher-quality welds.

A helmet that’s too dark or has too many variations in the quality of sight through its filter can cause discomfort, vision problems and even irregular welds. Think of a high-quality auto-darkening helmet and its cartridge in the same way as you think of your TV. You want to watch sports and movies in crystal-clear high definition, not on an old, grainy analog screen, right? Shouldn’t you want the same viewing quality from your welding helmet?

The Importance of Optical Clarity


That’s where optical clarity comes in. While the United States hasn’t yet adopted any formal requirements for welding helmet design, manufacturers, including Lincoln Electric, are finding guidance in the third-party European Standards that govern eye and face protection for the welding industry. Prefixed by EN (European Norm), the standard that governs auto-darkening welding helmet cartridges is known as EN379 and incorporates important ratings for optical clarity.

These ratings are determined by tests that measure light transmission across the welding cartridge, as well as scattered light from the cartridge’s layers. Rating tests occur in each of the following four classes of optical clarity:


Optical (accuracy of vision) — Qualifies how distorted the image is when you look at it through a welding helmet lens. Is it like looking at something through rippled water or is it clear and crisp?

The Importance of Optical Clarity


 Diffusion of light — Examines the manufacturing impurities in the cartridge’s glass. Is it clear and defect free? Is it uniform?

The Importance of Optical Clarity


 Variations in luminous transmittance (light or dark areas within the lens) — Focuses on the lens’ adjustable shade function and consistency of this shade across different points of the lens surface. No random areas should be too bright or too dark in comparison to others

The Importance of Optical Clarity


Angle dependence on luminous transmittance — Tests for a clear view without stretching, dark areas, blurriness or problems viewing things at an angle, as the result of inconsistent shade

The Importance of Optical Clarity

Cartridges are graded on a scale of 1 to 3 in each class. A score of 1 is perfect, while a score of 3 is the worst rating. The best rating is 1/1/1/1. Auto-darkening welding helmets rated with EN379-1/1/1/1 for optical clarity deliver even shade levels across the full height and width of the viewing area, which offers little, if any, distortion of view from clear, uniform glass.

While the EN379-1/1/1/1 rating is not a requirement in the United States, it does offer a known benchmark for quantifying lens clarity. Not all U.S. manufacturers use this rating, but Lincoln Electric is a pioneer in incorporating this standard into our helmet design and manufacturing process. In fact, our NEW VIKING™ auto-darkening cartridges for the 1840, 2450 and 3350 series offer a perfect EN379-1/1/1/1 optical clarity rating.

There’s a real benefit to undergoing the testing to achieve this rating, even though it isn’t required: It eliminates the guesswork involved in trying on helmets and determining by trial and error which one offers the best viewing lens. Now, when you’re looking to upgrade your helmet, you will know that one with a 1/1/1/1 optical clarity rating will deliver a perfect view and the best quality lens.

The Importance of Optical Clarity

Experienced welders who already have used a 1/1/1/1-rated helmet report they immediately can tell the difference in optical clarity. They say they can see better, the workpiece is clearer and the overall experience is more comfortable than using a helmet with, say, a rating of 1/2/1/2. These welders also have said they see the arc with less distortion with the higher-rated lens and have noticed clarity issues in helmets with a lower rating. While these parameters might be subtle, professional welders can and do notice the difference between 1 and 2 and a huge difference between 1 and 3.

These differences can play a role in overall productivity. If you’re looking through a distorted lens with impurities and inconsistent shade, your eyes will strain to see what you are doing. This could cause you to work harder. Viewing your welds through a clearer, better-quality lens allows your eyes to work longer with less fatigue and also less overall strain on your body.

These days, selecting an auto-darkening helmet involves more than just pulling one off of the shelf, putting it on and striking an arc. Optical clarity plays a major role in the decision process, moving from a factor that once was hard to determine without trial and error to something that can be identified through quantifiable benchmarks and ratings. The demand for better optical clarity in auto-darkening helmets is increasing in the United States, and Lincoln Electric is helping make it happen.

Download Practical Welding Today Article

View Lincoln Electric Welding Helmets