What is the Difference Between BL and BLB Blacklights?

The fluorescent blacklight category consists of bulbs with phosphors that create a peak wavelength at 365 nanometers. This part of the spectrum is called UV-A, and it is just inside the boundary with visible light. However, UV-A bulbs are considered ultraviolet bulbs as their peak wavelength is in the ultraviolet part of the spectrum.

Blacklights have two different designations, which you can usually find at the end of the part number for a given bulb. These designations are BL and BLB. Both of them emit the same UV-A wavelength, but one blocks out most visible light where the other does not.

BL Blacklight Bulbs

BL blacklights look just like standard fluorescent light bulbs. They are used for insect traps, tanning beds, UV curing, phototherapy, and other ultraviolet applications where visible light along with the UV is not a problem.

Common BL Blacklight Applications

• Insect Control Lighting
• Ultraviolet Curing Equipment
• Tanning Beds
• Phototherapy
• Low Level Disinfection

BLB Blacklight Bulbs

BLB blacklights, by contrast, are easy to spot with their dark blue filter that covers the bulb. The filter blocks most visible light, leaving only a faint violet glow when the bulb is turned on. BLB blacklights are used for special effects and inspections such as mineral analysis. They can also be used to detect organic materials like searching for evidence of bed bugs.

Common BLB Blacklight Applications

• Fraud Detection
• ID Inspection
• Organic Waste Detection
• Stage/Studio Special Effects
• Mineral Analysis

Is UV-A Dangerous?

UV-A is relatively low power, longer wavelength ultraviolet light and is considered the safest of the UV spectra. It is still prudent to avoid long exposure times, especially if looking directly at the light.

UV-A light is not usually utilized for germicidal lighting purposes, as the exposure times to damage microbes are very high. However, there are some light fixtures that utilize UV-A for low levels of disinfection. The benefit is that the light can be used unshielded in occupied spaces. This is a very uncommon use for UV-A, though, as UV-C lamps and even UV-B light bulbs have more germ-killing efficacy.