We’re frequently asked if we can create a special ink that can be seen by a cell phone camera but not by the human eye. They frequently go on to say that the camera cannot have any special filters or illumination. With such constraints, the answer is, no.
There is, however, an exception!
Such inks can be created with the use of specific lighting, camera modifications, or filters. However, most cameras feature an electrical flash that may be used to stimulate a certain sort of ink.
Camera Flash Ink (CFI) and Camera Flash Pigment are two unique inks and pigments that we offer (CFP). On some surfaces, such as paper, the CFI and CFP can be made undetectable. When a consumer uses the camera flash to take a picture, the ink shows up in the picture.
Can Phone Cameras See UV Rays
Using the CFI and CFP, you may create a poster or photograph in which the camera can see what the human eye cannot
The camera phone’s silicon sensor can sense more wavelengths in the ultraviolet (UV) and infrared (IR) for UV and IR photography, but all stock color cameras also feature an IR Cut Filter (ICF) that blocks those UV and IR frequencies.
Most people prefer the camera image to seem like what they perceive with their eyes, which is why manufacturers include an ICF. You wouldn’t be pleased if you shot a photo of your mother outside in the sunlight, but the colors were dreadfully off.
As can be seen, an ICF is required for a regular camera sensor to produce a color-correct image. Some items may appear to be correct, but many will not due to differences in IR and UV absorption and reflectance.
The resulting image is also affected by the illumination spectra, so an image taken in direct sunshine with UV, visible, and infrared light will seem differently than one taken inside a room with no windows and lighted by fluorescent lights, with practically exclusively visible light.
A camera with no ICF will take generally color correct photographs in a fluorescent light room. Incandescent (hot bulbs with filaments) emit visible and infrared light, whereas fluorescent lights emit almost exclusively visible light. Fluorescent light bulbs, by the way, are more energy efficient than incandescent lights.
“I read on the internet that if you point a remote control at the camera and the phone sees a light flash from the remote, the phone can sense infrared since the remote is delivering an infrared signal,” another response I got.
It’s close, but it’s not quite there. Yes, most remote controls send remote control codes through an IR Light Emitting Diode (LED). The IR LED, on the other hand, is pulsing at a very high power level. Some IR passes through the ICF and is detected by the camera.
Because no filter is perfect, some undesirable light makes its way through. However, because the ICF is good at blocking IR and excellent at passing visible light, even if you had a special ink that can be seen in the IR but not in the visible (we make some of these inks), you wouldn’t be able to see it in outdoor sunlight because visible light is passed at nearly 99 percent while IR is blocked at about 1%.
An IR long pass filter (which we make) with IR LEDs behind the IR filter is one technique to make an invisible message visible to a user using a stock camera phone. To the naked eye, the IR filter seems to be black glass, although it is virtually totally transparent to IR light (opposite of the ICF). If the IR LED is bright enough, it will pass through the ICF of the camera, but only the black filter glass will be visible to the naked eye.
Other options exist, but they need the use of specific filters on the camera or the modification of the camera and unique lighting.
UV radiation has a significant impact on human health. Nowadays, most people learn about UV radiation from weather forecasts, which can only provide a general and average projection for a given large area. Smartphones have the potential to be the ideal tool for measuring UV radiation because CMOS sensors in smartphone cameras are particularly sensitive to it. At the same time, using fog computing, result optimization may be done in real time since fog servers can gather UV radiation data and compute the results in local locations. This study went over in detail an innovative approach for measuring UV radiation using smartphone cameras, as well as how to use fog computing to improve UV measurement accuracy. An Android app named UV meter was created to carry out the procedure. Experiments were carried out on both smartphones and smart watches, using the app to validate and evaluate the procedure’s correctness and precision. The proposed approach achieved an average of 95 percent accuracy of a typical professional digital UV meter, and it could be simply implemented on smart devices, according to the findings.
This phone includes an unintentional X-ray vision filter that allows it to see through plastic and clothing.
Here’s a smartphone camera trick we’ve never seen before: The ability to see through X-rays. Or, at the very least, anything that like it. It’s a feature of the new OnePlus 8 Pro, which appears to see through a tiny subset of black materials using the phone’s infrared sensors.
If you have a OnePlus 8 Pro and want to test it out, simply open the camera app, slide to the “Photochrom” color filter, then point it at some dark things.
Fair warning: we tested the filter ourselves and found it to be extremely discriminating. It only works on very thin black plastic that is slightly translucent in the appropriate light. Instead of the tougher plastic of a high-end DSLR, consider items like TV remotes. Clothing might also be hit or miss.
This trick was first seen on Twitter (above) by Ben Geskin, but it has now been proven by a slew of other individuals. Unbox Therapy has a nice video (below) that shows the filter in action on an Apple TV box, a Switch remote, and even a thin black T-Shirt.
But how does it function? We contacted OnePlus to find out what they knew, but they declined to respond. The procedure, however, appears to rely on the phone’s infrared sensors, which capture a sort of radiation that is invisible to the naked eye.
Infrared is a part of the electromagnetic spectrum that lies just below visible light and is commonly referred to as “heat radiation” because of how we perceive its effects. The world is saturated in infrared, but we don’t notice it because we can’t see it. For example, around half of the energy that the Sun sends to the Earth comes in the form of infrared.
Infrared radiation can be captured using special equipment such as night vision goggles and thermal cameras. This enables you to see through some materials because infrared light can pass through them in a manner that visible light (which is what our eyes see) cannot. Infrared cameras, for example, are used by firefighters to see through smoke into burning structures.
As high-end phones begin to include infrared sensors, it appears that they can be used for the same purpose. It isn’t just the OnePlus 8 Pro that is capable of this. As software developer Guilherme Rambo has showed, the TrueDepth camera on current iPhones, which uses infrared light to scan your face for FaceID, can also be hacked to make see-through photographs (though it seems you need a jailbroken iPhone to do this).
The question now is if this will cause problems for OnePlus, particularly if the filter can be used to look through clothing, with all the privacy issues that involves. The filter appears to be able to see through clothing in the Unbox Therapy video, however only in extremely limited circumstances. The same was confirmed by a Reddit member.
OnePlus may have to disable the feature via a software update, depending on the severity of the issue. After all, Sony was forced to recall a camera with a night vision capability that could also be used to see through garments in the 1990s due to a similar scandal.
Enjoy peering inside your TV remote until then. If you have an iPhone 8 Pro and have tried out the feature, please share your photos in the comments section. If and when we hear back from OnePlus, we’ll update this story. Finally, Can Phone Cameras See UV Rays? Yes, they can.