The Three Types of Light Produced in Welding Operations (Explained Safely)

It was 9 p.m. when Dana finally got up from the couch and headed for the bathroom mirror. A few hours earlier she had spent maybe fifteen minutes watching a coworker TIG weld behind an open screen, no shield, no glasses. Now it felt like someone had poured sand under her eyelids, and the light in the hallway made her squint. By midnight she could barely open her eyes. Dana had arc eye, caused by welding radiation she never saw coming.

The Three Types of Light Produced in Welding Operations: The Short Answer

It was 9 p.m. when Dana finally got up from the couch and headed for the bathroom mirror. A few hours earlier she had spent maybe fifteen minutes watching a coworker TIG weld behind an open screen, no shield, no glasses. Now it felt like someone had poured sand under her eyelids, and the light in the hallway made her squint. By midnight she could barely open her eyes. Dana had arc eye, caused by welding radiation she never saw coming.

Her problem was never a lack of toughness. It was a lack of information about what an arc actually throws at you.

The Direct Answer

The three types of light produced in welding operations are ultraviolet (UV) radiation, visible light, and infrared (IR) radiation. Welders and regulators often call this energy radiant energy or light radiation, and OSHA’s guidance on eye protection during welding and cutting is blunt about it: the electromagnetic energy given off by an arc or flame can injure workers’ eyes and skin (OSHA Fact Sheet on Eye Protection against Radiant Energy).

All three sit on the same electromagnetic spectrum, ordered by wavelength. Ultraviolet occupies the short-wavelength, high-energy end just above what we can see. Visible light is the narrow band our eyes detect, roughly 380 to 750 nanometers. Infrared sits just below visible light, with longer wavelengths and lower photon energy but plenty of thermal punch. The important part: an arc does not send out one type at a time. It emits all three simultaneously, in a single continuous blast, whether you are running stick, MIG, TIG, plasma, or an oxy-fuel flame.

Visible light is only a tiny slice of the whole spectrum. Below it lie infrared, microwaves, and radio waves; above it sit ultraviolet, X-rays, and gamma rays, as the CDC’s overview of the electromagnetic spectrum explains (CDC: The Electromagnetic Spectrum).

Why Each Type Hurts Differently

The reason this topic deserves a full article rather than a one-line answer is that the three types of light cause three different kinds of harm:

• Ultraviolet burns the cornea and the skin. It is invisible, it reflects off concrete and metal, and it is the main reason welding helmets exist.
• Visible light causes glare, temporary flash blindness, and eye strain. It is the type you can see, and the reason shade numbers matter.
• Infrared delivers heat that can damage the eye’s lens and retina, and it heats exposed wrists, forearms, and chest.

Notice that the hazard is not the same as the sensation. You see the visible glare instantly and blink. The UV and IR work on tissue whether or not you feel anything at the time, and the pain from arc eye typically arrives hours later. The HSE lists arc eye as an acute injury to the cornea caused by welding radiation, with pain and redness starting after a delay rather than on contact (HSE: Health risks of welding).

One more distinction worth locking in early: welding light is a different hazard from welding fumes. Fumes are a respiratory problem you inhale; radiant energy is a surface problem that hits your eyes and skin. You need ventilation for one and shielding for the other. Confusing the two is how people end up wearing a respirator under an open helmet, protected from nothing that matters most.

Roadmap of This Guide

We will first look at the physics of the arc, so the spectrum stops being abstract. Then each type gets its own section: ultraviolet as the everyday damage dealer, visible light as the reason shade selection is a real skill, and infrared as the heat hazard people underestimate. After that comes a side-by-side comparison, practical protection guidance built around OSHA’s shade recommendations, the mistakes that cause most injuries, and checklists you can use at your station tomorrow.

Whether you are running your first bead on aluminum with a Aluminum MIG Welding: The Complete Practical Guide setup, troubleshooting wire-feed issues in Aluminum Flux Core Welding: What Actually Works in 2026, or prepping clean plate, the light hazard behaves the same way. The process changes the intensity and the mix, not the rules. Every arc process and every oxy-fuel flame produces ultraviolet, visible, and infrared radiation to some degree, and the sooner you treat that as a constant rather than a background detail, the longer your eyesight lasts.

Why Welding Radiation Is Different: The Physics of an Electric Arc

“Welding light” sounds like simple brightness. What comes off an arc is actually a broad band of radiant energy spanning wavelengths your eyes can see and, more importantly, wavelengths they cannot. To understand how a fifteen-second glance can put you in a dark room for two days, you need a working picture of what an arc actually is.

What an arc really is: a column of plasma

An electric arc is a sustained plasma discharge between an electrode and the workpiece. Plasma is matter energized enough that electrons are stripped from their atoms, leaving a mix of charged particles that conducts electricity easily. The CDC’s radiation health resources note that ionization is produced by very high temperatures, electrical discharges, or nuclear radiation, and a welding arc delivers the first two at once.

That plasma column runs at many thousands of degrees Celsius, hot enough to melt steel. Here is the key physics point: the hotter a source is, the shorter the wavelengths it emits and the more energy each photon carries. A bonfire glows deep red and throws off mostly heat. A welding arc, far hotter, pushes hard into the ultraviolet end of the spectrum while still producing visible light and infrared. It is the same reason a heating element glows dull orange while an arc looks blindingly blue-white.

Wavelength, frequency and energy in plain English

Light travels as waves. Wavelength is the distance between two wave peaks, measured in nanometers (nm), and frequency is how many waves pass a point each second. The relationship is simple, and it drives everything in welding safety: the longer the wavelength, the lower the energy of the radiation.

• Ultraviolet (UV) sits just below visible light, with short wavelengths and high photon energy. Push past violet light and you get UV, then X-rays and gamma rays, each step carrying more energy per photon.
• Visible light occupies a narrow band of roughly 380 to 750 nm, violet to red. Red carries less energy than violet.
• Infrared (IR) sits just above visible light with long wavelengths. Each photon carries less energy than a UV photon, but IR arrives in such volume that we feel it as heat.

This is why welding radiation is classified as non-ionizing radiation: the arc’s UV, visible and infrared output sits below X-rays on the energy scale. It is a different hazard from welding fumes, which you inhale, and you control it with barriers, distance and filtration rather than ventilation alone.

The mix is not fixed: your setup changes the output

Not every arc emits the same balance of the three types. According to CDC/NIOSH welding health research, the rate of ozone formation in a welding area depends on the wavelengths and intensity of ultraviolet light generated in the arc, which are in turn affected by the base material, electrode type, shielding gas, process, and welding variables such as voltage, current and arc length. Your machine settings partly determine what comes out of the arc.

• Shielding gas composition shifts arc constriction and temperature. Argon-rich mixes, helium blends and CO2-heavy gases each change how tightly the arc focuses and how much UV it pushes out, which is why settings in an aluminum MIG setup cannot simply be copied to mild steel.
• Electrode type and coating matter. A basic stick rod and a heavily alloyed or iron-powder-coated rod behave differently in the arc, covered in depth in alloy steel welding electrode selection guides.
• Current and arc length scale intensity. Longer arcs at higher voltage expose a longer plasma column to open air, increasing UV output.
• Process choice is the biggest lever. Carbon-arc gouging and air arc processes run exposed arcs that throw extreme visible and UV light, which is why air arc welding procedures treat screening as mandatory rather than optional.

Oxy-fuel belongs here too. An oxy-acetylene flame is cooler than an arc but still emits ultraviolet, visible and infrared light, with a different spectral signature: flames lean heavily toward infrared and visible output, while arcs push more UV. That is why torch work feels like radiant heat on your face while arc work burns your eyes. Flame settings and torch technique are covered in air acetylene welding basics.

Distance and reflection: the two factors people forget

Radiant intensity falls off sharply with distance. For a roughly point-like source such as an arc, exposure drops with the square of the distance, so doubling your distance cuts exposure to roughly a quarter. A bystander three feet away is in a far different hazard zone than one ten feet away, which is why OSHA’s welding hazard guidance emphasizes screens and separation rather than trusting distance alone.

Reflection is the quieter problem. UV bounces off concrete floors, unpainted block walls and bright metal. Aluminum, stainless and mill-finished plate are efficient reflectors, so prep work that leaves metal bright also makes the bay brighter in ways you cannot see. Reflected UV reaches around corners and over screens, meaning someone with their back to the arc is not automatically safe. The UK’s HSE welding health risk guidance treats both direct and reflected exposure as real, which is exactly the trap that catches helpers and adjacent tradespeople who never strike an arc themselves.

Now that you know where the light comes from and what shapes it, the next three sections look at each type individually, starting with the one that causes the most everyday damage: ultraviolet radiation.

Type 1: Ultraviolet (UV) Radiation From the Welding Arc

Of the three kinds of light an arc throws off, ultraviolet is the one that quietly does the most damage on an average workday. OSHA lists exposure to ultraviolet (UV) radiation among the health hazards from welding, cutting, and brazing operations, and for good reason: the arc produces UV-A, UV-B and at least some UV-C wavelengths all at once. The shorter the wavelength, the more energy it carries, and UV sits on the energetic end of the electromagnetic spectrum.

Near the arc, UV intensity can be far higher than sunlight at noon. That is why fifteen seconds of unprotected staring matters more than an hour at the beach. You do not feel UV arriving, and you cannot see it, so your body gets no warning at all.

What UV Actually Does to Skin and Eyes

The eye injury most welders know by name is photokeratitis, commonly called arc eye or welder’s flash. The UK Health and Safety Executive describes arc eye as an acute injury to the front of the eye, the cornea, after exposure to radiation generated by welding, and notes that the eye normally becomes painful and red a few hours after the exposure. That delay is the trap. You finish the shift feeling fine, and the pain arrives at home.

• Typical onset: a gritty, sandy sensation beginning 4 to 12 hours after exposure, worse in bright light, with redness, tearing and squinting.
• Skin response: erythema, a reddening like a patch of sunburn, sometimes with peeling a day or two later.
• Longer-term concerns: increased skin cancer risk and ocular melanoma, a rare eye cancer the HSE associates with welding, particularly the ultraviolet radiation generated.
• Secondary effect: UV reacting with oxygen in air forms ozone, an irritant that adds to respiratory discomfort in poorly ventilated booths.

The same HSE guidance points out that welders’ skin can be exposed to ultraviolet radiation causing erythema, and separately that nickel and chromium released during welding may cause allergic contact dermatitis. Radiation and chemistry hit the same forearms from two directions, which is a strong argument for sleeves rather than bare skin.

You Do Not Have to Look at the Arc to Get Burned

Here is the part that catches experienced tradespeople off guard: UV does not require direct line of sight. It bounces. Concrete floors, painted walls, stainless workpieces, a polished tabletop, even a coworker’s reflective vest will throw UV around a shop. Someone standing around the corner with their back to the arc can still receive a meaningful dose. Welding a reflective alloy job such as an alloy wheel makes the problem worse, because the curved polished surface acts like a shallow mirror.

This is exactly why shade filter lenses exist and why screens are not optional decoration. The dark filter in a welding helmet is built primarily to knock down UV to a safe level, with visible brightness handled as a secondary job. It is also why stick welding in an open bay without a curtain puts everyone nearby at risk, not just the person striking the arc.

Practical Controls for UV

1. Wear a helmet with a filter lens rated for the process and current, and keep safety glasses on underneath for the moments the helmet is up.
2. Cover skin fully: long sleeves, gloves, and a closed collar. Bare wrists and open necks are where the “welder’s tan” shows up first.
3. Screen the arc with weld curtains or portable barriers, and orient the booth so the arc faces a wall rather than a walkway.
4. Assume reflective surfaces spread UV. Check what is behind and beside you, not just what is in front.

If you are learning the fundamentals in a structured setting, a proper aluminium welding course covers UV control early, because aluminium work tends to involve wide, reflective surfaces and frequent out-of-position tacks.

UV is the reason the helmet exists, but it is only one-third of the story. The light you can actually see brings its own, more immediate problems, and that is where shade numbers start to matter.

Type 2: Visible Light — Glare, Flash Blindness and Why You Need Shade Numbers

Of the three kinds of radiation an arc throws off, visible light is the one you can actually see, and it’s the one most welders think about first. It’s also the reason a welding filter exists in the first place. Where ultraviolet burns you silently and infrared cooks you with heat, visible light attacks through sheer intensity: glare that washes out your vision, temporary flash blindness the instant your eyes are uncovered, and the eye strain that piles up over an eight-hour shift. According to the CDC’s overview of the electromagnetic spectrum, visible light occupies a narrow band of roughly 380 to 750 nanometers. That thin slice is the only part of the arc’s output your retina can register, which is exactly why it feels like the whole hazard.

Why Arc Light Is So Intensely Bright

An welding arc is a plasma column burning at thousands of degrees, and hotter sources push more of their energy into shorter, brighter wavelengths. The result is a visible output that can be thousands of times brighter than ordinary room lighting, concentrated into a point the size of a pencil tip. Your pupils constrict, your retinas saturate, and for a few seconds after you look away you simply cannot see properly. That’s flash blindness. In a shop, it’s not a discomfort, it’s a trip hazard, a grinder hazard, and a reason the welder turns toward a darker work area while their vision is still recovering.

This is also why a plain pair of sunglasses is nowhere near enough. Sunglasses reduce brightness by a modest, uniform amount; they are not rated for light radiation, they don’t block the arc’s ultraviolet properly, and they do nothing against infrared. Only a filter lens with a rated shade number is designed for the job.

Shade Numbers: The Practical Answer to Visible Glare

A filter lens shade number describes how much light the lens absorbs, with higher numbers meaning darker. The correct shade depends on the process and the current, because amperage drives arc intensity. OSHA 1910.133(a)(5) puts the duty squarely on the employer: each affected employee must use equipment with filter lenses of a shade number appropriate to the work being performed, to protect against injurious light radiation.

Here’s the core of OSHA Table E-1, the minimum protective shade table most shops use as a starting point:

Process	Current	Minimum Shade
SMAW (stick)	Under 60 A	7
SMAW (stick)	60–160 A	8
SMAW (stick)	160–250 A	10
SMAW (stick)	250–550 A	11
GMAW/FCAW (MIG/flux core)	Under 60 A	7
GMAW/FCAW (MIG/flux core)	60–160 A	10
GTAW (TIG)	Under 50 A	8
GTAW (TIG)	50–150 A	8
Plasma arc welding	20–100 A	8
Plasma arc welding	100–400 A	10

Shade selection is always a trade-off. Too light and the glare burns through; too dark and the welder can’t see the puddle. The real danger of “too dark” is behavioral: a welder who can’t see will flip the helmet up, squint at the arc, and take the full force of visible light, ultraviolet and infrared straight to the eye. That’s how the $30 lens fails. For an example of how process choice changes everything downstream, see Aluminum Flux Core Welding: What Actually Works in 2026, where wire type, amperage and puddle visibility all pull against each other.

Auto-Darkening Doesn’t Replace Shade Selection

Auto-darkening helmets darken in a fraction of a second and are a genuine comfort upgrade, but they don’t make the shade table obsolete. Every ADF helmet still has a selectable shade range, usually adjustable in discrete steps (for example 9–13), and the same process-and-amperage logic applies. Setting an ADF helmet to its lightest shade for a high-amperage pass gives you the same unprotected glare you’d get from a fixed lens that’s too light. A passive fixed-shade lens, by contrast, is simply a piece of filtered glass at one rated shade: cheaper, more reliable, and sometimes the better choice for a specific, consistent process.

Whichever you wear, the standard is the same. OSHA requires filter lenses rated for the work, safety eyewear underneath for grinding and helmet-up moments, and screens so that visible glare doesn’t blind the coworker standing three feet behind you. The next section looks at the third type of light: the invisible heat of infrared.

Type 3: Infrared (IR) Radiation — The Invisible Heat Hazard

If ultraviolet is the invisible burn and visible light is the blinding glare, infrared is the part of the arc you feel. IR is the heat-carrying portion of the welding spectrum: your skin registers it as warmth on your forearms, and your face feels it the moment you strike an arc. You never see it, because IR sits just beyond the red end of visible light. That combination, invisible but physically felt, is exactly what makes it easy to underestimate.

How IR Heats Skin and Eyes

Infrared energy is absorbed by tissue and converted directly into heat. Skin warms quickly, which is why exposed wrists, forearms and the upper chest are the classic injury sites. The pattern is predictable: a welder in a short-sleeve shirt with an open collar holds position over a fillet, and within minutes the skin on the wrists and along the collarbone is reddened, sometimes blistered. It is not a spark burn. It is radiant heat doing what radiant heat does.

The eyes are more vulnerable still. IR passes through the cornea and is absorbed by deeper structures, raising temperature in the lens and retina. Sustained exposure is linked to thermal damage of the cornea and to chronic changes in the lens. The occupational cataract long associated with glassblowers and furnace workers, sometimes called “glassblower’s cataract,” is the classic example of what cumulative IR exposure can do over years rather than minutes. Retinal concerns also exist with intense, prolonged exposure, which is one reason a filter lens matters even on processes you would not consider “hot.”

OSHA is explicit that eye and face protection is required where employees are exposed to potentially injurious light radiation, including from flying particles, molten metal and chemical gases or vapors, as set out in 29 CFR 1910.133. A rated filter lens under a proper helmet is the difference between protection and a tinted lens that quietly lets the heat through.

IR Adds to Total Heat Stress

IR is not only an eye hazard; it is a whole-body thermal load. In a hot shop, in summer, or inside a confined space, radiant heat from the arc stacks on top of ambient temperature, physical effort and non-breathable clothing. The result is faster fatigue, heavier sweating and a rising risk of heat illness.

Confined and enclosed spaces make this worse on two fronts at once. They trap radiant and convective heat, and they can displace oxygen, so radiation exposure compounds with asphyxiation risk. The UK’s HSE advises that welding in confined spaces should only be carried out when absolutely necessary, and where it is necessary it demands ventilation, air monitoring and a rescue plan. In those settings, radiation controls only work when paired with airflow and monitoring, not on their own.

Where IR Comes From

Every arc process produces IR, and high-current work such as Advantages of Stick Welding: Why SMAW Still Wins delivers plenty of it. Oxy-fuel welding, heating and cutting are equally important sources: a flame is cooler than an arc, but it throws a broad, steady band of IR that you can feel on your hands and face from a comfortable distance. Thermal radiation from the hot workpiece itself continues after the arc stops, which is why leaning over a fresh weld still burns.

Why a Helmet Alone Is Not Enough

Here is the part most welders get wrong: IR passes through many common materials. Thin cloth, synthetic shirts and anything short-sleeved offer little resistance. Dense, opaque materials do. Leather, wool and flame-resistant fabrics absorb and block IR far more effectively, which is why a leather welding jacket, gauntlet gloves and a leather bib or apron genuinely reduce exposure rather than just looking the part.

That is also why IR control is a three-part job:

• Shade selection — a properly rated filter lens blocks the IR that reaches your eyes.
• Clothing — long leather or FR sleeves, gauntlet gloves and a closed collar protect skin from radiant heat.
• Screens — welding curtains and barriers reduce the IR that reaches everyone else in the bay.

A helmet protects your face and eyes, and nothing else. Combine it with the right shade, the right sleeves and the right screens, and IR becomes manageable — the same layered approach described in Aluminum MIG Welding: The Complete Practical Guide. Skip any one layer, and the heat finds the gap: a wrist under a rolled cuff, a collar left open, a bystander standing two meters away with no barrier between them and the arc. OSHA’s welding hazards and solutions guidance treats this layered approach — eye protection, skin coverage and screening — as the baseline expectation, not best practice.

How the Three Types of Welding Light Compare: Intensity, Penetration and Distance

Ultraviolet, visible light and infrared all leave the arc at the same instant, but they travel differently. One burns the cornea, one blinds you with glare, one cooks tissue with heat. Comparing them side by side makes the hazards easier to reason about, and it shows why a single helmet lens has to solve three problems at once.

UV, Visible and IR at a Glance

Feature	Ultraviolet (UV)	Visible Light	Infrared (IR)
Wavelength range	Approx. 100–400 nm (UV-A, UV-B, UV-C)	Approx. 380–750 nm	Above approx. 750 nm into the millimetre band
Energy per photon	Highest	Moderate	Lowest, but delivered as heat
Main health effect	Photokeratitis, skin erythema, long-term cancer risk	Glare, flash blindness, eye strain, accidents	Corneal and lens heating, skin burns, cataract risk
Main control	Filter lenses plus screens and distance	Correct shade number, orientation, screens	Clothing, sleeves, gloves, shade and screens
Visible to the eye	No, which is what makes it sneaky	Yes	No, but felt as warmth

The invisible types are the ones people underestimate. You cannot see UV building up on your forearms or IR heating the lens of your eye, so neither triggers the instinct to look away. Visible light at least warns you with glare. The CDC’s explanation of the electromagnetic spectrum sets out the underlying rule: shorter wavelengths carry more energy per photon, while longer wavelengths deliver more of their effect as heat.

Why Distance Is the Cheapest Control You Have

Radiant intensity from a point source falls off with distance following roughly the inverse square relationship: double your distance from the arc and the exposure you receive drops to about a quarter. That single fact is why OSHA’s guidance on eye and face protection treats screens and physical separation as legitimate controls rather than courtesy. The same principle protects passers-by, not only the person striking the arc.

Distance is not the only variable. Exposure changes with the process, amperage, arc length, and whether the arc is open or shielded. A long arc on high-amperage stick welding throws out more of everything than a short, tight TIG arc at low current. A shielded arc with a gas lens still emits UV; the shielding gas manages the weld pool, not your cornea. Work in a booth near a reflective wall and you are effectively standing closer to more than one source.

Arc Welding Versus Oxy-Fuel Welding and Cutting

An oxy-fuel flame is cooler and less intense than an electric arc, so it produces far less UV. But it is not radiation-free: the flame emits all three types with a different spectral signature, leaning heavily on IR and visible light. Prolonged unprotected staring at an oxy-fuel flame can produce arc-eye-like symptoms even though nobody is striking an arc. Heating and cutting add another layer, because the glowing steel itself becomes an IR source long after the torch is set down. This is the same reason Air Arc Welding and Carbon Arc Gouging demands the same discipline as welding: the process couples intense radiation with other hazards in one work area.

Reflected Radiation: The Hazard That Keeps Going

Three kinds of reflection matter in a real shop:

• UV bouncing off walls, roofs and metal. It still burns skin and corneas, and it does not care whether you were looking at the arc.
• Glare reflecting off the workpiece. This is what causes the disoriented look-away moment when a welder turns toward a darker area with dilated pupils.
• IR radiating from hot metal. The heat keeps arriving after the arc stops, which is why a welder leaning close to a freshly welded joint still feels it on the face and chest.

Reflectivity is a practical planning variable: a matte, light-absorbing booth surface is genuinely safer than a bright, polished one.

Why Bystanders Get Hurt

Radiant energy does not stop at the person who lit the arc. OSHA’s eye protection fact sheet for welding specifically addresses workers in shipyard employment exposed to radiant energy, which tells you the hazard is treated as a shared-area problem, not a personal one. Plenty of helpers, fitters and adjacent tradespeople develop arc eye without ever striking an arc themselves.

Radiation is also rarely alone. The UK’s HSE notes that noise from processes such as air arc gouging at 100–115 dB(A) and plasma cutting at 98–105 dB(A) frequently co-occurs with radiation hazards in the same work area, and that welding in confined spaces or in areas where sound reflects, such as a workshop corner, produces higher exposures than open-space welding. Controlling one hazard while ignoring the others leaves the job half-protected.

Every booth layout decision, screen placement and distance rule is therefore a bystander control as much as a welder control. If you can see someone else’s arc from where you stand, their radiation can see you too.

Choosing the Right Protection: Shade Numbers, Helmets, Screens and Clothing

Knowing that a welding arc throws out ultraviolet, visible and infrared radiation is only half the job. The rest is what you put on and set up before the arc starts. Almost all of it comes back to one small number stamped on a filter lens, plus the clothing and screens that handle what the lens cannot.

Start With the Shade Number, Not the Helmet

Filter lenses are rated in shade numbers, running from about shade 3 (lightest) up to shade 14 or higher (darkest). A higher number means a darker filter. The right shade depends on two things: the process you are running and the current or material thickness involved. OSHA’s eye protection standard includes a table of typical selections, and the common starting points look like this:

Process	Current / condition	Recommended shade
SMAW (stick)	Under 60 A	7
SMAW (stick)	60–160 A	8
SMAW (stick)	160–250 A	10
SMAW (stick)	250–550 A	11
GTAW (TIG)	Under 50 A	8
Plasma arc welding	20–100 A	8

Notice the pattern: crank up the amperage and UV and visible output climb with it, so the filter has to get darker. If you are unsure, the full OSHA 1910.133 standard carries the complete table, and the OSHA eye protection fact sheet for welding condenses the same guidance into one page you can post at a station. Shade selection is a balance between protection and visibility; process-specific guides such as our Aluminum MIG Welding: The Complete Practical Guide spell out the currents where that balance shifts.

Helmet Styles, Prescription Lenses and the Z87.1 Mark

• Passive fixed-shade lenses are inexpensive, rugged and have no electronics to fail. The trade-off is that you change the lens when the process changes.
• Auto-darkening helmets switch to the dark state the instant the arc is detected, which helps with tack welds, starts and awkward positions. They do not make shade tables irrelevant: you still set the shade (or choose a lens whose range covers your work), and a helmet set too light lets UV straight through.
• Flip-up and combination units let you pop the filter up for setup, grinding or inspection while keeping a clear or tinted cover underneath.
• Prescription wearers need eyewear that either incorporates the prescription or fits over existing glasses without shifting them out of position.

Those last two points are regulatory, not optional. Under OSHA 1910.133(a)(3), employees who wear prescription lenses must use protection that incorporates the prescription or can be worn over the lenses without disturbing their position. Devices themselves must comply with ANSI/ISEA Z87.1 as referenced in OSHA 1910.133(b), must carry side protection when flying objects are a hazard under 1910.133(a)(2), and must be distinctly marked to identify the manufacturer under 1910.133(a)(4). If your helmet or glasses have no Z87 mark, they are not rated for the work.

One rule worth repeating: wear Z87 safety glasses under the helmet. They cover you while you grind, while the helmet is flipped up, and whenever a stray spark or grinding particle comes in from the side. They do not replace the filter, but the filter does not replace them either.

Cover the Skin: The Other Half of Protection

UV does not care that you are looking away. Welders get a “welder’s tan” on the neck, ears and forearms, and the classic failure point is short sleeves with an open collar, which burns the wrists and chest. Long sleeves, a leather or flame-resistant welding jacket, gauntlet gloves, a leather apron and a cap under the helmet close those gaps. This also handles infrared, a heat hazard as much as a light one that still passes through some thin or untreated materials. A helmet alone never counts as full-body protection, so sourcing rated gear matters as much as the helmet you pick.

Area Controls: Screens, Signs and Sightlines

None of the above protects the person walking past your booth. Weld curtains and fixed screens keep UV and glare inside the bay, warning signs stop curious traffic, and orienting booths so the arc faces a wall rather than a walkway removes most bystander exposure in one layout decision. For gas work, OSHA 1910.252 requires goggles or other suitable eye protection during all gas welding and oxygen cutting, with spectacles without side shields permitted only for light gas work, torch brazing or inspection.

Complaint	Likely cause	Fix
“It’s too dark, I can’t see the puddle”	Shade too high for the process, or poor lighting	Drop one shade; add task lighting
“It’s too light, I’m squinting”	Shade too low for the amperage	Step up a shade per the OSHA table
“My eyes ache by the end of shift”	Marginal shade, scratched lens, or no under-glasses	Replace the lens; add Z87 safety glasses
“My forearms are red tonight”	Sleeves rolled or jacket unzipped	Full-length FR or leather sleeves, gloves, apron
“The helper got flashed again”	No screen, or booth faces a walkway	Install curtains, reorient the booth, post signs

Work through that table before you blame the equipment: most complaints are shade selection, missing clothing, or an unscreened arc, and all three are fixed the same afternoon.

Common Mistakes, Misconceptions and Real-World Failure Scenarios

The Ten Mistakes That Cause Most Welding Light Injuries

Nearly nobody gets hurt because they didn’t know arcs emit ultraviolet, visible and infrared radiation. They get hurt from a shortcut, a wrong assumption, or a habit that worked a hundred times before it failed once. These are the failures that recur in shops, shipyards and garages.

1. Assuming only the welder needs protection. UV doesn’t check who is holding the stinger. Bystanders, fitters and anyone walking past an open booth take the same cornea-burning radiation at a lower dose. Protection is a zone, not a helmet.
2. Wearing sunglasses or clear safety glasses as welding protection. Ordinary tinted eyewear blocks almost none of the harmful UV from an arc. Clear safety glasses stop spatter and grit but do nothing meaningful for radiation. They supplement a filter lens, never replace it.
3. Using a fixed-shade lens set for the wrong amperage. A shade 7 lens under 250 amps of stick welding passes far too much visible and UV energy. A shade 12 on a 40-amp TIG bead is so dark you can’t read the puddle.
4. Lifting the helmet while the arc is live. The quick look at the finished bead with the electrode still hot is the classic flash-burn trigger. Half a second of unprotected exposure is often enough.
5. Welding in a t-shirt or with rolled-up sleeves. Forearms, wrists and chest take heavy UV and IR exposure. A short-sleeved welder may not notice the burn until the drive home.
6. Skipping the screen because it’s “just a quick tack.” A tack weld emits the same arc as a long weld. Duration changes the dose, not the hazard.
7. Assuming auto-darkening helmets make shade tables irrelevant. An ADF controls reaction time, not exposure limits. You still select the correct shade range for the process and current, and many helmets have dials owners never touch.
8. Using cracked, pitted or fogged lenses. Damaged cover plates scatter light and let stray radiation leak around the edges. A scratched $5 cover lens undermines a $200 helmet.
9. Ignoring reflected UV. Radiation bounces off concrete, bright walls, stainless workpieces and polished fixturing. You can be flashed by an arc you never directly saw.
10. Writing off small daily exposures. No single short flash hurts, so the habit looks safe. Cumulative UV exposure to the eye and skin is linked to cataracts and skin cancer over a working lifetime.

Scenario: The Welder Who Was Never Flashed

Marcus, an aluminum fabricator with eight years in the trade, prided himself on never getting arc eye. He ran an auto-darkening helmet, kept his lens in good shape and changed shades reasonably well. But his booth sat opposite a freshly painted white wall, and he frequently tacked aluminum sheet with shiny fixture plates close to his open left side. He never looked at the arc unprotected. He didn’t need to.

Over several months he developed persistent redness in both eyes, gritty dryness by mid-afternoon, and a habit of squinting on the drive home. The skin on one forearm stayed oddly tanned, then flaky. Nothing ever happened dramatically, which is exactly the problem. Reflected UV and stray glare accumulated day after day, and no single day looked severe enough to force a change.

It took a supervisor hanging a welding curtain along the walkway, turning the booth away from the bright wall and getting Marcus proper sleeves before the eye fatigue settled down. The arc was never the whole hazard. The room was.

It Is Not Just the Welder’s Call: The Employer’s Legal Duty

These are not only personal safety failures; they are compliance failures. OSHA 1910.133(a)(1) requires employers to ensure each affected employee uses appropriate eye or face protection when exposed to flying particles, molten metal, light radiation or chemical splashes. OSHA 1910.252 sets general requirements for welding, cutting and brazing, including eye protection during gas welding and oxygen cutting. A shop that lets a welder work in a t-shirt, runs arcs beside an unscreened walkway, or leaves a station with no posted shade reference puts the responsibility on the employer, not just the worker.

This is hardly an exotic hazard. The UK Health and Safety Executive estimates that breathing metal fume at work leads to roughly 40 to 50 welders being hospitalised each year, a reminder that welding injuries are routine rather than rare. Add HSE and IARC’s classification of all welding fume as a Group 1 carcinogen, and the message is the same: treat radiation control as ordinary daily discipline, not an emergency measure.

Fixing these mistakes costs almost nothing: a curtain, a correct shade, a sleeve, a replaced cover lens. Skipping them is what turns invisible radiation into a career-shortening injury.

Practical Tips, Checklists and Workplace Controls That Actually Work

Knowing that a welding arc emits ultraviolet, visible and infrared radiation only helps if that knowledge shows up at the workstation. This section is the playbook: short checklists you can run in under a minute, a shade table you can post on the wall, and a clear plan for what to do when someone’s eyes do get burned.

The Pre-Task Checklist

Run this every time you strike an arc, not just at the start of a shift:

• Identify the process and amperage. Stick, MIG, TIG, plasma and oxy-fuel all produce different amounts of UV, visible light and IR. Amperage drives intensity, so check the machine setting rather than guessing. Electrode choice matters too, which is why guides like alloy steel welding electrodes always pair filler selection with recommended current ranges.
• Select your filter shade using the process and current from the table below.
• Inspect the lens. Cracks, pits, deep scratches and fogging scatter light straight into your eyes. Replace it before you weld.
• Confirm side shields and safety glasses. Prescription safety eyewear with side protection is required under OSHA 1910.133, and it stays on under the helmet for grinding and for the moment you flip the hood up.
• Cover skin: long sleeves, welding gloves, and no rolled cuffs or open collars.
• Set up curtains and screens before the first tack, not after someone complains.
• Clear bystanders from the line of sight and rotate barriers if the work position changes.

Booth Setup Checklist

• Screens should reach roughly head height and block the arc from walkways, adjacent stations and windows.
• Orient the booth so the arc faces a wall, never a corridor or open door.
• Keep floors and nearby walls dull. Shiny concrete, polished stainless and bare metal decks bounce UV and glare back at everyone nearby.
• Leave enough distance between booths that one welder’s arc is outside another’s normal field of view.
• Post signage at the entrance so no one walks in unshielded.
• Check sightlines from every angle a coworker might appear from, including from above on multi-level work.

Quick-Reference Shade Selection

OSHA’s rule of thumb is simple: start with a shade too dark to see the weld zone, then switch to a lighter shade that still gives you a sufficient view, without ever dropping below the minimum for your process. Shades denser than those listed may be used to suit the individual’s needs, which matters for workers sensitive to bright light. OSHA publishes the full values in Table E-1 of its welding hazards guidance.

Process	Condition	Minimum shade
Oxyfuel gas welding	Light (under 1/8 in / 3.2 mm)	4
	Medium (1/8 to 1/2 in)	5
	Heavy (over 1/2 in)	6
Oxygen cutting	Light (under 1 in)	3
	Medium (1 to 6 in)	4
	Heavy (over 6 in)	5

If Something Goes Wrong

Arc eye: symptoms typically appear several hours after exposure, with gritty pain, redness, tearing and light sensitivity. Rest in a dark room, do not rub the eyes, and use lubricating drops only if advised. Seek medical care for severe pain, vomiting, blurred vision or any change in sight. Skin that feels sunburned needs cooling and coverage; both eye and skin injuries should be reported and logged so the exposure source gets fixed.

Maintenance That Keeps Protection Working

• Replace cover lenses when scratched or hazed; clean auto-darkening sensors with a soft, dry cloth so they darken reliably.
• Test auto-darkening helmets before each shift and replace batteries on schedule, keeping spares at the station.
• Store helmets out of direct sun and away from heat, with the inner lens facing down and PPE dry and damage-free.
• Check hearing protection fit too. The HSE notes that ear plugs or slimline muffs with neckbands often fit under a welding hood better than standard headbands, the same compatibility question you ask of safety glasses.

Employer-Level Controls

Individual habits only go so far. Employers should train every worker and apprentice on shade selection and screening, supervise new welders closely during their first months, post the shade table at each station, and review near-miss reports where someone was flashed. Structured training, such as a formal aluminium welding course, builds that foundation early. OSHA’s welding, cutting and brazing standard and its eye protection fact sheet spell out the duty: protect the welder and everyone standing near the arc.

Conclusion: Seeing the Invisible to Weld Safely for a Career

Go back to Dana. She never saw anything dangerous happen. No bright flash, no dramatic spark shower, no moment where she thought that was stupid. She just stood near an arc for fifteen minutes without a shield, and by midnight she could barely open her eyes. That is the whole problem in one sentence: the light that hurts you most is the light you cannot see, and the punishment always arrives after the crime.

One answer deserves saying plainly one more time. Welding operations produce three types of light: ultraviolet radiation, visible light, and infrared radiation. Every time you strike an arc, whether it is stick, MIG, TIG, plasma or flux core, and every time you light an oxy-fuel torch, all three arrive together as one package. Ultraviolet burns the cornea and skin and raises long-term cancer risk. Visible light delivers glare and flash blindness that can send a welder stumbling into a hazard. Infrared carries heat into the skin, the lens and the retina, and keeps radiating off hot metal long after the arc is dead.

Why the Invisible Half Matters Most

UV and infrared are invisible, which tricks people into a dangerous habit: they judge risk by brightness. If it does not look bright, it feels safe. But arc eye and welder’s sunburn do not begin at the moment of exposure. They build silently over hours, which means your body’s own warning system is always a shift behind the damage. By the time your eyes sting, the exposure is already finished and the injury is already written. That delay is why engineering the exposure out of the job, rather than trusting your instincts, is the only reliable strategy. The HSE is blunt about this: awareness of the hazard changes nothing on its own. It is exposure control and properly used PPE that actually reduce welding health risks.

A Career-Long Investment, Not a Purchase

Here is the arithmetic welders eventually learn the hard way. A decent filter lens costs very little. A pair of welding sleeves or a leather jacket costs less than a weekend’s spending. Decades of clear vision, unburned skin and a retina that still works properly are essentially priceless. Every hour you spend with the wrong shade, an open collar, or a cracked, pitted lens that scatters light is a withdrawal from an account you cannot refill. The rules are not suggestions either: OSHA 1910.133 requires eye and face protection appropriate to the hazard and a filter lens with a shade number appropriate to the work being performed. The shade table exists because the physics is not negotiable.

None of this is exotic; it shows up in ordinary work. Someone running Advantages of Stick Welding: Why SMAW Still Wins on thick plate needs a far darker filter than someone doing light TIG work. A student walking into an Aluminium Welding Course learns shade selection in the first week, because aluminium reflects UV hard and punishes anyone who skimps on screens.

What Dana Would Do Differently

Safety glasses on under the helmet, always, so protection stays in place when the helmet goes up. A screen around the arc, even for a two-minute job. A shade matched to the actual current, not whatever lens was already in the hood. Long sleeves, gauntlet gloves, collar closed. And stop treating a tack weld as too small to control: a tack produces the same three types of light as a full weld, just for less time.

Here is your homework, and it takes five minutes. Check your lens for cracks and pits. Check your shade against the process and amperage. Check your sleeves and your collar. And check who is standing behind you, because the person most likely to get flashed is rarely the person holding the stinger.

Frequently Asked Questions

What are the three types of light produced in welding operations?

They are ultraviolet (UV) radiation, visible light, and infrared (IR) radiation. Every arc or flame process emits all three at the same time, and each one can harm the eyes and skin in a different way. This is why a welding helmet with the correct filter shade, plus skin coverage, is needed rather than ordinary sunglasses.

Which of the three types of welding light is the most dangerous?

Ultraviolet radiation causes the most immediate and well-documented injuries, including arc eye (photokeratitis) and welder’s sunburn, and is linked to skin cancer and ocular melanoma. Infrared is also serious because it damages the eye lens and skin through heat, but it is often overlooked because it is invisible.

Can you get arc eye from watching someone weld for a few seconds?

Yes. Very short unprotected exposure to bright arc radiation can cause photokeratitis. Symptoms such as a gritty feeling, redness, tearing and light sensitivity typically appear a few hours later, which is why the injury is often noticed in the evening after a daytime job.

Do auto-darkening helmets protect against all three types of light?

A quality auto-darkening helmet protects against UV, visible and IR radiation in its darkened state, and many provide UV and IR protection even before the lens darkens. You still need to select the correct shade for the process and current, keep the lens clean and undamaged, and wear safety glasses underneath.

What shade lens should I use for MIG, TIG and stick welding?

Under US OSHA guidelines, stick welding at 60 to 160 amps generally calls for at least shade 8, and 160 to 250 amps calls for shade 10. MIG and flux-cored welding at 60 amps or more typically needs shade 10, and TIG welding below 50 amps needs shade 8. Always confirm against the OSHA shade table and your own comfort and visibility.

Is infrared radiation from welding strong enough to burn my skin?

Yes. Infrared is heat, and repeated or prolonged exposure can burn skin, especially on forearms, wrists and the chest when sleeves are open or rolled up. It also contributes to eye damage and adds to overall heat stress, so leather or flame-resistant sleeves and gloves are important even in warm weather.

Do I need to protect people working near me who are not welding?

Yes. Ultraviolet and visible radiation reflect off surfaces and travel, and coworkers, helpers and nearby tradespeople can develop arc eye without ever striking an arc. Use weld curtains or screens, orient booths away from walkways, and warn others before striking an arc.

What should I do if I think I have arc eye?

Rest your eyes in a dark room and do not rub them. Over-the-counter lubricating drops may help mild discomfort, but if the pain is severe, lasts more than a day, or comes with vision changes, seek medical attention. Report the exposure so the cause can be corrected instead of repeated.