How It Works
How Does the Infrared Filter Work
The inks or dyes that are used to create colors in fabrics reflects and absorb the different frequencies of visible light. However, Infrared light has a longer wavelength or lower frequency as shown by the bar graph below.
Many dyes, inks and synthetic fabrics are insensitive to these longer wavelengths of light, thus allowing it to penetrate it. When the fabric is exposed to an intense amount of infrared light, the IR light will pass through the fabric and reflect off the object behind the fabric and pass back through the fabric to the IR camera. Thus, when an infrared camera looks at a synthetic piece of fabric that has a dye that is insensitive to IR light,the fabric will appear to have lost its color and become sheer.
The IR camera works best on synthetic fabrics such as polyester, rayon, silk, nilon and not very well on anything with cotton in it. Colorfull patterns and dark fabrics are ideal for penetration. However, white fabrics don’t work well. White fabrics tend to reflect the infrared light instead of allowing it to pass through the fabric. The Ideal Creation IR filter when placed in front of a cell phone camera will remove 99.5 percent of visible light while allowing infrared light to pass through to the camera. Thus, the cell phone camera will become an infrared camera.
Normally a high quality digital camera will remove almost all of the infrared light to see colors accurately like the human eye. When a person looks through the IR filter it appears to be black. The reason for this is that the human eye can not see infrared light. Cell phone cameras tend to use cheaper CCDs that leaks infrared light into the camera, thus allowing it to see infrared light. The Ideal Creation IR filters are specially tuned for maximum performance for the cell phone camera. Two different filter are offered, a 750nm and a 800nm. The 750nm filter will work on almost all cell phone cameras, however it does not have the penetration power as the 800nm filter.
The 800nm is deeper into the IR spectrum which makes it work better. However, a little more than half of the cell phones don’t work with the 800nm filter because the camera can not see into the deep infrared light spectrum. The image will appear to be dark or grainy if the filter is too strong for the camera.