No, X Ray film is not safe for direct solar viewing because it fails to block enough invisible but harmful ultraviolet and infrared radiation, putting your eyesight at serious risk.
Millions of people search kitchen drawers or old photo albums when an eclipse approaches, hoping to improvise a filter. X Ray film often shows up at the top of the rummage pile. It looks dark. It was used around powerful radiation. It feels sturdy. All of that makes it seem like a clever hack, yet looks can be dangerously deceiving when you point your eyes at the Sun.
Why People Reach for Old X Ray Film
An eclipse is an event that sneaks up on most of us only a few times in life. When official eclipse glasses sell out, last minute creativity kicks in and X Ray film seems like a logical substitute.
The nostalgia factor reinforces that impulse. Many of us remember older relatives casually peeking at previous eclipses through a strip of processed medical film. That memory creates a false sense of security, but two things have changed. Modern X Ray technology now uses much faster digital detectors, so older, denser film is harder to find. More important, eye safety research is clearer than ever: even the blackest sheet of film does not meet the international ISO 12312‑2 standard for eclipse filters.
A 2021 survey by the American Astronomical Society found that nearly sixteen percent of respondents considered using “dark photographic or X Ray film” if they could not buy proper glasses. That number shows how deeply the myth persists, even among people who care enough to answer a science survey.
How Much Light Does X Ray Film Really Block?
Most folks judge a filter by how dim the world looks through it. The eye, however, is a poor light meter, and brightness alone tells only half the story. Infrared and ultraviolet rays are invisible, yet they are exactly what scorch the delicate tissues inside the eye.
Below is a simplified comparison of common improvised filters published by the Royal Astronomical Society of Canada and updated for clarity.
| Material | Visible Light Transmission (approx.) | Ultraviolet Blocking | Infrared Blocking | Meets ISO 12312‑2 | Verdict |
|---|---|---|---|---|---|
| Commercial eclipse glasses | 0.0003 percent | 99.99 percent | 99.99 percent | Yes | Safe |
| Two layers of exposed X Ray film | 0.03 percent | 50–70 percent | 10–20 percent | No | Unsafe |
| Standard sunglasses (darkest legal shade) | 3–10 percent | 98 percent | 20–40 percent | No | Unsafe |
| Welder’s glass shade 14 | 0.0006 percent | 99.9 percent | 99.9 percent | Yes | Safe |
The numbers jump out. Even two stacked sheets of X Ray film let through hundreds of times more infrared radiation than a certified eclipse filter. You may not feel any heat on your face, but inside your eye the temperature can soar by dozens of degrees within seconds. Retinal tissue has no pain receptors, so damage accumulates silently and can become permanent.
What Eye Doctors and Safety Standards Say
Dr. Rachel Bishop, former chief of consult services at the National Eye Institute, has a blunt take: “If the filter is not certified, assume it is dangerous. The retina heals poorly, and some damage will never improve.”
Multiple professional bodies echo that warning.
- The American Academy of Ophthalmology states that uncertified film “does not provide adequate protection regardless of how dark it appears.”
- NASA’s eclipse safety guidelines list X Ray film among filters that “should never be used under any circumstance.”
- ISO 12312‑2, the global testing standard for solar viewers, requires visible light transmission below 0.00032 percent plus near total blocking of wavelengths from 200 to 1400 nanometers. No X Ray film has passed that test.
Dr. Bishop notes that peak cases of solar retinopathy often present one to four days after an eclipse. Symptoms include a central blind spot, warped lines, or a yellow spot on the retina visible only to a clinician. Sadly, treatment options are limited and improvement, if any, can take months.
Persistent Myths Debunked
The same questions pop up every eclipse cycle. Let’s tackle the biggest ones.
“Because it blocks X Rays, it must block sunlight too.”
- X Ray photons are thousands of times more energetic than visible light. The silver compounds that stop X Rays do very little against near infrared.
“Two or three layers will make it safe.”
- Stacking reduces brightness but also increases reflections between layers, letting even more heat linger near the eye.
“My grandparents used it and their vision is fine.”
- Survivorship bias is at work. Many people experienced minor damage without realizing it, and those who did suffer noticeable harm rarely advertise the fact.
“If I only glance for a second I’ll be okay.”
- During an eclipse your pupils dilate because the Moon blocks part of the Sun, letting more invisible radiation enter. Even brief looks can be risky.
Safe and Affordable Alternatives
Hunting for a certified filter does not have to dent your wallet. With a little planning you can enjoy the spectacle without pricey gear or risky shortcuts.
Certified eclipse glasses remain the simplest option. They cost about the same as a fancy cup of coffee, slip easily into a pocket, and weigh almost nothing. When buying, look for “ISO 12312 2” printed on the inside of one lens and verify the seller on the American Astronomical Society’s approved list. If you already own a pair from a previous event, check for scratches or pinholes by holding them up to a bright lamp. Any leak of white light means they belong in the trash.
Another solid choice is shade 14 welder glass. These rectangular plates are made for professional welding helmets, so they block essentially all wavelengths that can hurt your eyes. They cost a bit more than eclipse glasses but last for years if kept in a padded envelope. Hardware stores and welding supply shops usually carry them in the protective eyewear aisle.
For anyone who likes hands‑on projects or wants to involve children in the fun, pinhole projection is perfect. A small piece of stiff card or even the colander from your kitchen will cast dozens of crescent shaped Suns onto the ground. You watch the shadows, not the Sun, making the method perfectly safe and entirely free.
Below is a quick snapshot that compares the main budget friendly options.
| Option | Average Cost per Person | Where to Buy or Find | Protection Level | Lifespan |
|---|---|---|---|---|
| Certified eclipse glasses (ISO 12312 2) | $2 to $5 | Science museums, astronomy clubs, online vendors approved by AAS | Blocks 99.99 percent of UV and IR | Single event if kept scratch free |
| Shade 14 welder glass | $10 to $15 | Hardware or welding supply stores | Blocks 99.9 percent of UV and IR | Years with careful handling |
| DIY pinhole projector | Free to $1 | Household items, craft stores | Indirect viewing so no direct eye risk | Reusable, unlimited |
| Solar filter sheets for binoculars or cameras | $25 to $40 | Telescope retailers, photographic suppliers | Meets ISO or CE standards when certified | Multiple events if stored flat |
Keep a few practical tips in mind:
• Place bulk orders of eclipse glasses with neighbors or coworkers to cut shipping costs.
• Tape a welder glass plate to a cardboard frame so it covers both eyes comfortably.
• If clouds roll in, keep glasses on hand. The Sun can emerge suddenly, and thin cloud does not block harmful radiation.
Affordable safety tools are available if you shop a week or two ahead of the event. A little preparation beats last‑minute improvisation every time.
Capturing the Moment Without Hurting Your Eyes
Photographing an eclipse tempts many first timers, yet camera sensors are vulnerable too. Use a genuine solar filter rated for photography on any lens or telescope. Relying solely on the camera’s internal shutter or a smartphone’s small sensor invites damage both to the device and, indirectly, to your eyes when you check the screen.
A safe workflow:
- Attach the solar filter before pointing the lens anywhere near the Sun.
- Frame and focus using live view at low screen brightness.
- Remove the filter only during the two or so minutes of totality when the Moon fully covers the Sun, and replace it immediately afterward.
Practicing the routine the day before helps prevent fumbling in the excitement of the moment.
FAQ
Can I test X Ray film with a UV flashlight to see if it is safe?
UV flashlights operate at different wavelengths than much of the Sun’s ultraviolet output, so passing that test does not guarantee safety.
Is undeveloped X Ray film better than processed film?
No. In fact, undeveloped film may transmit even more dangerous radiation because the silver salts have not been converted into dense metallic silver.
Does regular camera film work if it is really dark or exposed multiple times?
Camera film blocks mainly visible light. It is inadequate against infrared and ultraviolet, making it unsafe for eclipse viewing.
Are polarized sunglasses better than ordinary sunglasses for an eclipse?
Polarization cuts glare but has little effect on harmful wavelengths. Polarized sunglasses alone are nowhere near safe for looking at the Sun.
What happens if I looked briefly and my eyes feel fine?
Symptoms of retinal injury can take hours or days to appear. If you notice blurry spots or distorted vision later, seek an eye exam promptly.
Can welders shade 12 glass be used in a pinch?
Shade 12 blocks most visible light but still lets through more infrared than recommended. Stick to shade 14 or higher.
Wrap‑Up
Protecting your eyesight takes only a certified filter and a bit of patience. Share this guide with friends so everyone can enjoy the next eclipse safely, and drop your questions in the comments below. Clear skies and safe viewing!
