Commercially available UVA light fixtures typically range in wavelength from 365nm to 405nm, with 365nm and 395nm considered the more dominant choices. It is a common consideration for choosing 365nm or 395nm in UV black light and fluorescence detection applications.
365 nm and 395 nm refer to the wavelengths of light in the ultraviolet spectrum. These wavelengths fall within the UVA range, often referred to as “blacklight” due to their ability to make certain materials fluoresce or emit visible light.
However, whether 365nm and 395nm have the same application? What is the difference between them? Let’s take a look together.
UVA and Black Light
Blacklight refers to a special type of UV lighting that uses primarily UVA light to produce a unique effect. Blacklight lighting utilizes UVA light to excite the fluorescent properties of a substance, causing it to emit visible light.
In dark environments, black light enables fluorescent materials such as fluorescent inks, fluorescent paints, and fluorescent stickers to emit bright colors, creating a very vibrant visual effect. This effect makes black lights very popular in the entertainment, decorative and special effects fields.
UVA light is a commonly used light source in black light because of its low energy and high penetrating power. In the solar spectrum, UVA light refers to the ultraviolet A band, which ranges in wavelength from 315 nanometers to 400 nanometers and is considered invisible light.
Why is light with wavelengths below 400 nm invisible to the human eye, yet the wavelength value is still very important? This is because the wavelength determines the application category of UV light. For example, 365 nm and 395 nm belong to the same category of UVA, while 300 nm belongs to UVB and 270 nm to UVC.
- UVA Lights Applications: fluorescence detection, detecting counterfeit banknotes, security markings, signs of blood and body fluids, etc.; curing inks, coatings, glues and resins; trapping insects.
- UVB Lights Applications: Medical treatment of skin disorders such as psoriasis and eczema; tanning to supplement the body’s lack of natural sunlight exposure, treatment of Seasonal Affective Disorder (SAD) and other psychological and physiological disorders related to lack of light; chemical treatments.
- UVC Lights Applications: Disinfection and sterilization; medical device disinfection, food processing, water treatment, and air purification.
365 nm VS 395 nm
Although both 365 nm and 395 nm are UVA lights, and produce black light and curing effects, and there is only a 30 nm difference, 395nm is closer to visible light (violet color) than 365 nm, so to the naked eye, 395 nm UV light appears purple in color.
365 nm goes “deeper” into the invisible UV spectrum than 395 nm does, containing less visible light and at a shorter wavelength, so to the naked eye, 365 nm UV light appears as a dull blue-white color.
Why is there a difference in visible light between 365nm and 395nm? 365nm does not only emit 365nm wavelength light, and 395nm does not only emit 395nm wavelength light.
365nm UV light and 395nm UV light emit the most energy at 365nm and 395nm, respectively, but they also emit considerable energy in the adjacent 350nm to 380nm and 390nm to 410nm ranges. 365nm and 395nm energies decrease along both sides of the 365nm and 395nm spectra.
Compared to 365nm, a larger portion of the 395nm spectral output occurs in the visible violet region, providing a stronger visual experience and making it suitable for use in entertainment venues or decorative lighting.
Conversely, the closer the 365nm spectral output is to the visible 400nm, the less energy there is. This difference makes 365nm LED the preferred choice for most UV-A applications.
Although the 365nm wavelength is deep in the invisible spectrum, 365 nm LED produces a small amount of visible “leakage” or radiation beyond the 365nm wavelength due to limitations in the design of the LED or material properties.
These visible components may be in the blue or white spectral range, resulting in a dull blue-white coloration of the lighting you observe, rather than the pure UV output of the desired single wavelength of 365nm.
Therefore, for some applications, especially those requiring precise UV output, it may be necessary to select a higher quality, professionally designed LED to minimize the effects of visible light “leakage” and achieve a UV output closer to the pure 365nm.
365nm for Fluorescence Detection
For fluorescent dyes and markers, banknotes and security markers, minerals and gemstones, white clothing and dental bleach, they absorb the most energy under UV irradiation at 365nm and re-emit it in the form of intense fluorescence. This makes the fluorescence effect most noticeable and intense when these substances are viewed at 365nm.
395nm for Black Light Illumination
UVA lamps at 395nm have a slightly visible purple color. This color effect is commonly used in entertainment venues, decorative lighting, and applications where a balance of fluorescence and visibility is desired.
The 395nm UVA wavelength is relatively safe and less energetic than the shorter 365nm UVA wavelength. With proper UV protection, it usually does not cause significant harm to humans or the environment.
| Wavelength | 365nm | 395nm |
| UV Range | UV A | UV A |
| Light Color | Blue-white | Purple |
| Energy | Higher | Lower |
| Efficiency | Lower | Higher |
| Cost | Higher | Lower |
| Applications | Fluorescence detection, pet urine testing | Black light illumination, stage effects, banknote detection, anti-counterfeiting |
Here to check our 365nm and 395nm UV LED Black Light Strips.
395nm/365nm Black Light LED Strip
