StupidQuestionFilter? Why doesn't detergent stain my whites?

July 28, 2007 1:00 PM

I just poured a cupful of dark blue liquid detergent and purple liquid stain remover over a load of white towels. Setting aside the admonition that I should have poured the detergent in BEFORE the clothes: why doesn't dark blue detergent turn white towels blue? I mean it obviously doesn't. But it seems counterintuitive. What kind of coloring is added to detergent that allows it to be blue and pretty but wash right away?
posted by Bud Dickman to Home & Garden (7 answers total)

It does, but only slightly blue and that makes them look more white.
posted by caddis at 1:13 PM on July 28, 2007

Bluing has been used in laundry products for over a hundred years. More recent improvements in laundry products have included "brightener" agents, that actually leave a residue of UV dyes in fabric, making clothing fluoresce in sunlight or UV, giving a much brighter appearance to light colors than they would otherwise have.
posted by paulsc at 1:26 PM on July 28, 2007

Also this was referenced in this post.
posted by MtDewd at 2:15 PM on July 28, 2007

I accidently poured some on a soft gray carpet and didn't think anything of it, but now I can't get the blue out.
posted by stormygrey at 2:30 PM on July 28, 2007

I think it would make a blue stain if you just poured it on and left it. As it stands, you're pouring it on and then immediately sticking it through the wash, where it lathers up then rinses away.

I think I have a stain on a sheet where I spilled some liquid Cheer and didn't wash it for a while.
posted by lampoil at 2:56 PM on July 28, 2007

Response by poster: So the blue color actually has a purpose, aside from just making it look nice. Cool. Thanks!
posted by Bud Dickman at 4:40 PM on July 28, 2007

I've had a few Pilot Precise pens "explode" in the washer. The pilot pens have a water soluble ink that's effect is so mild that, even on white clothes, I didn't even bother rewashing the clothes before I put them in the drier.

I chalked this up to the fact that the ink must have been very dilute, even with a whole pen full of ink, and that the very dilute ink it never got a chance to dry and bond to the material before the rinse cycle.
posted by 517 at 10:23 PM on July 28, 2007