CFL "Blacklight" Bulb, retail $9.99 (
Manufactured by Mr Light (
Last updated 06-11-10

This is a fluorescent "blacklight" (produces UVA radiation; aka. "longwave ultraviolet"); its primary purpose is to cause fluorescence (glowing) in a variety of materials and objects.

This bulb would be most likely to get used on Halloween; though you most certainly aren't limited to using it just on that one day.

It is advertised to use just 13 watts at 120 volts. I measured this at 10.40 watts using a "Kill-A-Watt" meter.

It comes equipped with a medium screw base (size E26 or E27) aka. "Edison base".

 Size of product w/hand to show scale SIZE

To use this bulb, just screw it into any light fixture with an E26 or E27 medium screw base.

The only warnings I have regarding its use are that it must ***NOT*** be used in a fixture controlled with a dimmer switch -- whether that dimmer is on the wall or in the fixture itself; and it must not be used in a fixture controlled by a photoelectric ("day/night") sensor. This bulb will rapidly (and possibly quite spectacularly) fail if this is don't want baby Emperor scorpions or mayfly larvae...I mean an UNWANTED FIRE!!!

This product is designed to be operated from "house current" (110 volts to 130 volts AC 60Hz with a sinusoidial waveform), not batteries of any type, so I do not have to tell you which part to remove, huck down the basement stairs into the room crawling with thousands of hungry carpenter ants, and then rather emphatically tell you not to.

This is a fluorescent light bulb, not a flashlight designed to be thrashed, trashed, and abused. So I won't throw it against the wall, stomp on it, try to drown it in the toylet bowl or the cistern, run over it, swing it against the concrete floor of a patio, use a small sledgehammer in order to bash it open to check it for candiosity, fire it from the cannoņata, drop it down the top of Mt. Erupto (I guess I've been watching the TV program "Viva Piņata" too much again - candiosity is usually checked with a laser-type device on a platform with a large readout (located at Piņata Central), with a handheld wand that Langston Lickatoad uses, or with a pack-of-cards-sized device that Fergy Fudgehog uses; the cannoņata (also located at Piņata Central) is only used to shoot piņatas to piņata parties away from picturesque Piņata Island, and Mt. Erupto is an active volcano on Piņata Island), send it to the Daystrom Institute for additional analysis, or inflict upon it punishments that a flashlight might have to have performed on it. So this section of the web page will be ***SIGNIFICANTLY*** more bare than this section of the web page on a page about a flashlight.

Photograph of the lamp itself operating.
The purple light you see here is ***SIGNIFICANTLY*** more intense than it is in reality!!!

Photograph of some UVA-sensitive objects fluorescing
(glowing) when exposed to the UVA radiation from this bulb.

Spectrographic analysis
Spectrographic analysis of this bulb shortly after startup.

Spectrographic analysis
Spectrographic analysis of this bulb after twelve minutes of warm-up.
Note that the spectral features in the NIR (longer than ~680nm) are now gone.

Spectrographic analysis
Spectrographic analysis of this bulb; spectrometer's response narrowed to a range between 175nm & 550nm.

USB2000 spectrometer graciously donated by P.L.

Test unit was purchased at a Bartell Drugs in Seattle WA. USA on 10-21-03 (or "21 Oct 2003" if you prefer).

UPDATE: 00-00-00

Much cooler-running than incandescent "blacklight" light bulbs
Much more UVA output than incandescent "blacklight" bulbs
Much longer expected life than incandescents
Uses a lot less power than incandescents

Runs a bit on the hot side at 170.00°F (76.67°C) -- this is what nocked that last ― star off

    PRODUCT TYPE: CFL (Compact Fluorescent Lamp) "blacklight" bulb
    LAMP TYPE: Fluoro tube
    No. OF LAMPS: 1
    BEAM TYPE: Toroidal (360°X, ~300°Y)
    CASE MATERIAL: Plastic & glass
    BEZEL: N/A
    CURRENT CONSUMPTION: Unknown/unable to measure (stated as 170mA at 120 volts AC 60Hz; measured at 10.40W on a KAW meter)
    WATER- AND URANATION-RESISTANT: Very light splatter-resistance at maximum
    SIZE: 6.50" L, 1.90" Dia.
    WEIGHT: Unable to weigh (no scale at my disposal)
    COUNTRY OF MANUFACTURE: Unknown/not stated
    WARRANTY: Unknown


    Star RatingStar Rating

CFL "Blacklight" Bulb *

Do you manufacture or sell an LED flashlight, task light, utility light, or module of some kind? Want to see it tested by a real person, under real working conditions? Do you then want to see how your light did? If you have a sample available for this type of real-world, real-time testing, please contact me at

Please visit this web page for contact information.

Unsolicited flashlights, LEDs, and other products appearing in the mail are welcome, and it will automatically be assumed that you sent it in order to have it tested and evaluated for this site.
Be sure to include contact info or your company website's URL so visitors here will know where to purchase your product.

This page is a frame from a website.
If you arrived on this page through an outside link,you can get the "full meal deal" by clicking here.