Black Light can be used for spectacular photography or just for having some photographic fun, but if you just want to try out a quick trick for testing your home for bacteria there is a way to do it for a couple of cents.
Turns out that a certain mix of sharpie ink will block all light but back light. The folks at Hefty.co made a quick tutorial on how it’s made.
You would need a blue Sharpie and a purple Sharpie and some tape. Applying two blue tape layers and one purple tape layer will act as a filter for the smartphone flash. In total darkness shining that flash onto anything will reflect any black light (or fluorescent emittance) from found objects.
The phenomenon is caused because some substance and bacteria tend to fluoresce in various colors when shown with black light. According to Wikipedia:
A Wood’s lamp [UV emitting light source, UT] is a diagnostic tool used in dermatology by which ultraviolet light is shone (at a wavelength of approximately 365 nanometers) onto the skin of the patient; a technician then observes any subsequent fluorescence. For example, porphyrins—associated with some skin diseases—will fluoresce pink. Though the technique for producing a source of ultraviolet light was devised by Robert Williams Wood in 1903 using “Wood’s glass”, it was in 1925 that the technique was used in dermatology by Margarot and Deveze for the detection of fungal infection of hair. It has many uses, both in distinguishing fluorescent conditions from other conditions and in locating the precise boundaries of the condition.
And the tape makes our phones act just as Wood’s lamp.
[tape on his smartphone and colors it in | h/t Rotem]
Totally wrong on many levels
And scrap you phone camera for any other normal use after
There’s a piece of tape over the flash. Doesn’t hurt the phone.
Gar Bielle this is right up your alley.
You know that this doesn’t really work right? You should probably test it before you post myths as fact. About as bad as Facebook trolls.
I doubt this actually works
Lolwut. There’s no way this works.
Can confirm this DOES NOT work! Even tried with extra layers of blue or purple.
Even if it does work (it’s certainly changing the color temperature of the flash, possibly into ultraviolet range), this only begs the question of why he took a photograph of his toilet? And what are we seeing fluoresce, anyway? Maybe I really don’t want to know. I mean, a black light poster would have been more impressive, and certainly have less of an ick factor…
So you didnt even try it and you criticize…
No. I didn’t criticize it, if you read what I wrote, I actually suggested that it could work (as opposed to the other folks here). I was criticizing his choice of test photographs.
This is a joke right?
Whether or not Sharpies work, it is urine that is fluorescing. Biological fluids, other than blood fluoresce under light >=450nm. Blood absorbs–turns black. A contrasting filter often makes makes viewing easier.
There’s so little DIY on this site, they’re reaching to this for content?
Try it before you say it doesn’t work because it worked for me using blacklight paint for the test…I even made a large filter for my flash and it works too.