Optical brighteners aren’t the same thing as blue dye, even though they have the same role. Optical brighteners absorb high wavelength (UV) light and re-emit it as blue light. This helps prevent the new particles from overpowering or covering the existing dye. Blue dye would just paint the clothing more blue, which usually isn’t what you want.
So in this case it isn’t just marketing bla bla for some old thing, it’s actually a new(er) thing that replaced the old thing.
MrsDoyle@lemmy.world 8 months ago
Well that unlocked a memory. I was on a road trip around California and stopped off in a small town to do my laundry. An elderly gent was already in the laundromat and the washing machine window showed bright, bright blue. He said he recalled that his late wife used to use blueing tablets to get the sheets etc white. “I couldn’t find any at the store, but these toilet cleaning tablets are blue, so figured I’d try them.”
This is what my late mother used: retonthenet.co.uk/vintage-washing-laundry-reckitt…
cheesymoonshadow@lemmings.world 8 months ago
Toilet cleaning tablets?!
MrsDoyle@lemmy.world 8 months ago
The kind that clip under the rim and turn the water blue. Some kinds you put in the cistern. i5.walmartimages.com/…/4e1b697a-ca2d-4243-96fd-b7…
cheesymoonshadow@lemmings.world 8 months ago
I know what they are, was just shocked he uses them for laundry. I can almost feel my skin breaking out in a rash just thinking about it.