Jump to content

Recommended Posts

Posted

Hello,

I just had a few questions about a black light that I bought: https://www.lowes.com/pd/Scorpion-Master-Mini-Flashlight-LED-Miniature-Flashlight-Battery-Included/3182999. It actually has a peak wavelength of 390 nm, and I was wondering if this thing had any chance of fading color off of shirts made from natural fibers (cotton, wool, etc.). I understand that the type of dye that was used is also important, but I do not know.

2.) If it does have that ability, I was wondering if anyone could explain why and how this particular flashlight has that capability.

3.) Is HDPE naturally resistant to this type of UV?

Thank you and I look forward to your responses.

 

Posted

If it does, it will tend to make red fade to a larger extent than other material. Red dye is red because the dye absorbs light that isn’t red.

The question is whether 390 nm (a little over 3 eV) is enough to break the dye’s bonds. 

Posted
20 hours ago, swansont said:

If it does, it will tend to make red fade to a larger extent than other material. Red dye is red because the dye absorbs light that isn’t red.

Since 390 nm is (practically)  invisible the extent to which a dye absorbs it has nothing to do with the color of the dye.

 

The extent to which teh dye fades also depends on the nature of the dye. It would take a while to fade cinnabar (OK that's a pigment, not a dye) which darkens with exposure to light.

The answer to the OP's question si also "it depends on the dye".

21 hours ago, kevinlee234 said:

 Is HDPE naturally resistant to this type of UV?

It should be.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.