When a solar eclipse is on the horizon, many people scramble for a safe way to watch, often turning to household items. An old X-Ray film might seem like a smart, DIY solution because of its dark appearance. However, using it to look directly at the sun is extremely dangerous. 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.
Why Do People Mistakenly Reach for X-Ray Film?
The impulse to use X-Ray film is understandable. Eclipses are rare events, and official eclipse glasses often sell out quickly. In a last-minute rush, the dark, sturdy feel of medical film makes it seem like a logical substitute for proper solar filters.
Many also have nostalgic memories of older relatives using a strip of film to peek at past eclipses. This creates a false sense of security, but times have changed. Modern eye safety research is much more advanced, and we now know the severe risks involved. A 2021 survey by the American Astronomical Society revealed that nearly sixteen percent of people would consider using X-Ray film, showing just how persistent this dangerous myth is.
Furthermore, the film itself has changed. Older X-Ray films were often denser, but modern digital imaging has made that kind of film rare. Even the darkest, oldest piece of X-Ray film does not meet the international ISO 12312-2 safety standard required for direct solar viewing.
The Hidden Dangers that Your Eyes Can’t See
It’s easy to judge a filter by how dark it makes the world look, but that’s a deceptive test. Your eyes are not good at measuring the full spectrum of light. The real threat comes from invisible infrared (IR) and ultraviolet (UV) radiation, which can scorch the sensitive tissues of your retina without you feeling a thing.
A certified pair of eclipse glasses blocks over 99.99 percent of this harmful radiation. In contrast, even two layers of X-Ray film let through hundreds of times more infrared light. While you might not feel any heat on your face, the temperature inside your eye can rise enough to cause permanent thermal damage within seconds.
How Improvised Filters Compare to Safe Viewers
The data clearly shows the failure of common household items as solar filters. The Royal Astronomical Society of Canada provides a stark comparison of how much dangerous radiation these materials let through.
| Material | Visible Light Transmission | Infrared Blocking | Meets ISO 12312-2 | Verdict |
|---|---|---|---|---|
| Commercial eclipse glasses | 0.0003% | 99.99% | Yes | Safe |
| Two layers of exposed X-Ray film | 0.03% | 10-20% | No | Unsafe |
| Standard sunglasses | 3-10% | 20-40% | No | Unsafe |
| Welder’s glass shade 14 | 0.0006% | 99.9% | Yes | Safe |
What Eye Doctors and Safety Experts Say
Medical professionals and scientific organizations are united in their warnings against using uncertified filters. Dr. Rachel Bishop of the National Eye Institute states, “If the filter is not certified, assume it is dangerous.” This is because the retina, the light-sensitive tissue at the back of your eye, does not have pain receptors. Damage can happen silently and may not be noticed until hours or even days later.
This condition, known as solar retinopathy, can cause a permanent blind spot in the center of your vision. Major safety authorities have issued clear guidelines:
- The American Academy of Ophthalmology warns that uncertified films like X-Ray film “do not provide adequate protection regardless of how dark it appears.”
- NASA lists X-Ray film among filters that “should never be used under any circumstance.”
- The ISO 12312-2 standard itself requires near-total blocking of UV and IR wavelengths, a test that no X-Ray film has ever passed.
Symptoms of solar retinopathy often appear one to four days after viewing an eclipse and can include blurry vision, distorted lines, or a yellow spot. Treatment options are very limited.
Debunking Common Myths about DIY Eclipse Viewing
Every time an eclipse approaches, the same dangerous ideas resurface. It’s crucial to understand why they are wrong. Believing these myths can lead to irreversible eye damage.
One common belief is that stacking multiple layers of film will make it safe. While stacking does reduce brightness, it fails to block enough infrared radiation and can even trap heat near your eyes. Another myth is that a very quick glance is harmless. But during an eclipse, your pupils are dilated, allowing even more damaging light to enter in a fraction of a second.
The argument that “my grandparents used it and they were fine” is a classic example of survivorship bias. We don’t hear from the people who did suffer vision loss, and many others may have sustained minor damage without realizing the cause.
Safe and Affordable Alternatives for Watching an Eclipse
Fortunately, protecting your eyes is both easy and affordable with a little planning. You don’t need to risk your vision with a dangerous shortcut. Certified eclipse glasses are the most popular option. They typically cost only a few dollars and are designed to block all harmful radiation. When buying, always look for the “ISO 12312-2” text printed on the glasses and purchase from a vendor on the American Astronomical Society’s approved list.
Another excellent option is shade 14 welder’s glass, which can be found at hardware or welding supply stores. It offers robust protection and is very durable. For a completely free and fun group activity, you can build a pinhole projector. This method allows you to watch a projection of the eclipse with your back to the sun, making it 100% safe.
How to Safely Photograph a Solar Eclipse
Your camera’s sensor is just as vulnerable to the sun’s rays as your eyes are. Pointing an unprotected camera or smartphone at the sun can permanently damage it. To take photos safely, you must use a certified solar filter that fits over your lens.
Never use your camera’s optical viewfinder to look at the sun, even with a filter on the lens. Instead, use the digital screen or live view to compose your shot. The filter should only be removed during the brief period of totality when the moon completely blocks the sun. Remember to put the filter back on the moment the sun begins to reappear.
Frequently Asked Questions
Is it safe to use multiple pairs of sunglasses to view an eclipse?
No. Stacking sunglasses, even polarized ones, does not block the dangerous infrared and ultraviolet radiation. They are not a safe substitute for certified eclipse glasses.
What happens if I glanced at the eclipse without protection but my eyes feel fine?
Symptoms of solar retinopathy, or retinal damage, can take hours or even days to become noticeable. If you experience blurry spots, distorted vision, or other changes, you should see an eye doctor immediately.
Can I use welder’s glass that is rated lower than shade 14?
No, only shade 14 or higher is considered safe for direct solar viewing. Lower shades, like 12 or 13, let through too much harmful infrared radiation.
Is undeveloped X-Ray film safer than developed film?
No, it is actually more dangerous. Undeveloped film has not yet converted its silver compounds into the dense metallic silver that blocks light, so it may transmit even more radiation.
