Summer's coming. Time for invisible dye.

May 19, 2009 8:20 AM

Sunscreen's a pain, but sunburn is worse. UV-protective clothing is expensive and not to everyone's taste. Instead, treat your own cotton, rayon, or silk clothing to make it sun-protective. Some clothing is inherently protective, but you can easily burn right through a new shirt, especially if it gets wet. A couple of boxes of either of two different brands of a wash-in UVA/UVB blocker will invisibly increase the SPF of a whole washer-load of clothing from 5 to 30 (repeat for an SPF of 50). The stuff wears off after a season's worth of launderings, so use a permanent marker to note the year of treatment inside the collars.
posted by Ery (52 comments total)

As a pale-ass Scot who burns like flashpaper I would like to state my undying hatred of the sun and all it's works.
posted by The Whelk at 8:22 AM on May 19 [1 favorite]

Putting on half the recommended amount of sunscreen is equivalent to replacing the SPF by its square root, via God Plays Dice.
posted by escabeche at 8:29 AM on May 19

Eh. Something's gonna kill every one of us eventually, no matter what new prophylactic we invent to prevent it. Put on a little sunscreen from a tube, and go out and enjoy the sun!
posted by M.C. Lo-Carb! at 8:31 AM on May 19

Pepsi Ultraviolet

you can easily burn right through a new shirt

what. Seriously, is there a link for this? Because I'm having a really hard time believing it. Ah. As suspected, it isn't a matter of cloth not blocking UV as wearing clothes full of holes lets in light. Which...duh.
posted by DU at 8:33 AM on May 19 [2 favorites]

As a pale-ass Scot who burns like flashpaper I would like to state my undying love for the sun's warming rays, and SPF 60. This wash-in UVA/UVB blocker seems like a scam to me though. Even my sensitive skin doesn't burn when clothed in a just about anything but a wet, white tshirt.
posted by caddis at 8:33 AM on May 19

I'm happy I learned these wash-in things exist, thanks... but I can't get over how this post reads like some kind of proactive Ask MetaFilter.

MeFi should have that. DidntAskMe.
posted by rokusan at 8:35 AM on May 19 [1 favorite]

Oh, but that said:

While there is some correlation between the amount of visible light that passes through a fabric and the amount of UV that passes the same fabric, it is not a strong relationship. Based on some of the new-technology fibers and textiles designed for the sole purpose of UV blocking, it is not always possible to gain a good understanding of the UV protection level of a fabric simply by holding it up and examining how much visible light passes through the fabric.

But that's not cited and I'm having a really hard time believing it. UV is not that far from the end of the blue end of the spectrum. Furthermore, it's shorter wavelengths, which should be easier to block (according to my hazy understanding of waves).
posted by DU at 8:36 AM on May 19 [1 favorite]

I burn through teeshirts all the time. It's why I have freckles in the damndest places.
posted by padraigin at 8:39 AM on May 19 [1 favorite]

If I shower with this stuff, can I skip the whole sunblock thing?
posted by orme at 8:41 AM on May 19

only for the next year or so
posted by caddis at 8:42 AM on May 19

Yeah, Solumbra is nice, but 1) it's geared primarily to women, 2) it's expensive as hell.

This is awesome, given all of the precautions I have to take (and will continue to take).

It's a pain to find a good UVA/UVB blocker in the SPF60 zone that doesn't make you look like a clown or give you zits.
posted by adipocere at 8:45 AM on May 19 [1 favorite]

This is why I chew Extra's chlorophyll gum.
posted by srboisvert at 8:47 AM on May 19

This is why I chew Extra's chlorophyll gum.

"I'm worried about Becky."

"What, why? Her lamentable fondness for drummers?"

"No, and shut up I like Chad. I think she's anorexic or something. She barely eats anything. She just chews gum all the time."

"Uh, status alert, Becky's a Leafhead. Like since forever."

"Leafwhat?"

"God it's like talking to a toddler. Leafheads, you know, the people with the green patches?"

"I thought those were tattoos?"

*sigh* "No, they are not. They're plant patches, you get them from chewing ChloroGum. "Eat like a tree and calorie free." Gives you a nice rush on sunny days. Don't worry bout Becky, she's totally not hardcore. The *real* Leafheads are *all* green and hand out creepy pamphlets at the park. . Seriously, you've never seen the "I AM NOT AN ANIMAL" t-shirts? You need to get out more and break that layer of Totally Frakin' Oblivious hanging on ya."
posted by The Whelk at 8:58 AM on May 19 [12 favorites]

you can easily burn right through a new shirt

Citation needed.
posted by Nelson at 9:00 AM on May 19 [2 favorites]

If you need me, I and my fish belly white skin are going to be hiding down here, in the dark windowless basement I live in. If you could send someone down with food, and a spray bottle to moisturize me every so often, I'd appreciate it.
posted by strixus at 9:02 AM on May 19

...or you could go in the other direction and wear clothing that lets more sun in.
posted by ZenMasterThis at 9:03 AM on May 19

I have used the Rit Sungard on our t-shirts for several years. My Irish and Scottish ancestry kids wear them in the pool, and at the beach, during the Southern summers, and we have had no sunburns. I just have to remember to wash all of the t-shirts at the beginning of the pool season with the Sungard. Unlike an untreated shirt, these don't seem to let the UV through when wet.
posted by Midnight Skulker at 9:06 AM on May 19

just one of us regular folk who happens to have a sun allergy

Wait, What? Who knew.
posted by Mitheral at 9:11 AM on May 19

Seriously, The Whelk and caddis, what has the sun done for us anyway? Excepting glaring down on us with its fiery Eye of Death, I mean?
posted by GenjiandProust at 9:14 AM on May 19

DU: UV is not that far from the end of the blue end of the spectrum.

A lot of it is, actually; UV goes all the way to 10nm.

I was dismayed to learn, at an embarrassingly advanced age, that UV is a larger chunk of spectrum than visible light is. (Infrared is larger still.) And UV is ionizing radiation. As far as I can tell, the main thing separating UV and ("soft") X-Rays is an imaginary line on the spectrum chart.

X-Rays have shorter wavelengths than, yet are not "easier to block" than, visible light.
posted by Western Infidels at 9:23 AM on May 19

Since the beginning of time, man has yearned to destroy the sun.
posted by The Whelk at 9:24 AM on May 19

Western Infidels: Most of that hard end of UV is absorbed by the atmosphere anyway. See how quickly the solar spectrum drops off at http://en.wikipedia.org/wiki/File:Erythemal_action_spectrum.svg
posted by edd at 9:28 AM on May 19 [1 favorite]

You can get sunburned through clothes? Tell that to my goofy looking farmer-tan.
posted by ElmerFishpaw at 9:36 AM on May 19 [6 favorites]

This is a good product for new clothing, if you're extremely sensitive to the sun.

Just be aware that most whiteners and brighteners have the same effect on your clothing after washing them 8 to 12 times. "Brighten" == "reflects more ultraviolet".

So clothes you've already had and washed several times for a summer are already safe, equivalent to SPF 15 or higher. For new clothes, the cost of the dye plus one wash probably balances the energy/water cost a dozen extra washes.
posted by Araucaria at 9:37 AM on May 19

http://en.wikipedia.org/wiki/Farmer_tan
posted by ElmerFishpaw at 9:37 AM on May 19

Is this something I'd have to not live in Seattle to care about?

(Looks out window. Sighs)
posted by hincandenza at 9:38 AM on May 19 [2 favorites]

This reminds me. It's almost June, I better get to work on my base tan.
posted by debbie_ann at 9:39 AM on May 19

The *real* Leafheads are *all* green and hand out creepy pamphlets at the park.

I don't care how creepy they are, I would go green in a heartbeat. How much simpler would life be without having to eat every N hours and forage (at the grocery store) every M days?
posted by DU at 9:45 AM on May 19

I have heard the same thing Araucaria mentions about repeated launderings increasing UV protection. And just to clarify a little bit, optical brighteners don't merely reflect UV, they actually absorb it and re-emit it as visible light; they are also used in the inks for black-light posters, for example. I would be interested to know if the active ingredients in the wash-in UV blockers are just optical brighteners being marketed in a new way, minus the detergent.
posted by TedW at 9:51 AM on May 19

Citation needed for getting a sunburn though new clothing? The text on the "treat your own" link above says that many summer clothes don't block all ultraviolet. The NPR report linked on that page says that a dry white cotton t-shirt has a UPF of 5 unless it's been washed many times with detergent that contains fluorescent brighteners, which can increase the UPF of old clothes up to ten-fold. (Thicker fabrics and some visible dyes also block more ultraviolet.)

White cotton t-shirt fabric is known to transmit a significant amount of ultraviolet light. Typical summer fabric does not protect against skin cancer, although fabric treated to yield an SPF of 30 does. Wetness increases the UPF of polyester fabric but decreases the UPF of cotton fabric.

Anecdotally, I've seen several nasty sunburns that occurred right through white cotton t-shirts. A Canadian friend got a blistering sunburn on a Texas beach while wearing a white t-shirt. A relative who borrowed a white cotton shirt from me for windsurfing got a nasty sunburn right through it. The following summer, the same relative borrowed a shirt I treated with the sunblocker for another sunny day of windsurfing, and did not get any sunburn at all. I like the treated shirts so that I don't have to bother with as much sunscreen.
posted by Ery at 9:53 AM on May 19

As an undying Scot who loves the pale....BRAINS!
posted by zerobyproxy at 9:56 AM on May 19

Well a little digging shows that the active ingredient in the Rit product I something called Tinosorb FD, made by Ciba, also called 2,2’-(1,2-ethenediyl)bis[5-[[4-(methylamino)-6-[[4-[(methylamino)carbonyl]phenyl]amino]-
1,3,5-triazin-2-yl]amino]-, disodium salt (CASRN 180850-95-7) on the MSDS. According to the second PDF on this search, it is indeed a laundry brightener. So these products seem to just be laundry soap additives minus the laundry soap and sold at a hefty mark-up.
posted by TedW at 10:09 AM on May 19 [3 favorites]

As a would-be pale ass Scot who's great-grandmother slept with a traveling Cuban band leader, I'd just like to say that SPF-4 and a Summer on the beach gives me the broziest South Bay surfer-boy tan you've ever seen.

Thanks great-grandma!
posted by Pollomacho at 10:09 AM on May 19 [1 favorite]

On the subject of sunscreen, can anyone share some good techniques for applying sunscreen to your own back?

(I ask the girls at the beach, but their boyfriends invariably kick sand in my face)
posted by Dr-Baa at 10:13 AM on May 19

I prefer to use butter...that way I can smell myself cooking in the sun.
posted by rand at 10:18 AM on May 19

Ask the boyfriends?
posted by Mitheral at 10:18 AM on May 19 [1 favorite]

As a would-be pale ass Scot who's great-grandmother slept with a traveling Cuban band leader, I'd just like to say that SPF-4 and a Summer on the beach gives me the broziest South Bay surfer-boy tan you've ever seen.

Thanks great-grandma!

As somebody with 15 stitches on a forearm where the doc scooped out some basal cell carcinoma last week (next week: same thing, other arm) -- I'd just like to say: Wear Sunscreen.

Thanks a fuckload, great-grandma!
posted by stupidsexyFlanders at 10:28 AM on May 19 [2 favorites]

I wear a long sleeve grey UV rashguard that I use for surfing anytime I'm at the pool. Being older, and thus totally out of touch with normal sartorial convention anyway, I'm not sure if what I'm doing is regarded as hideous, comical, sad, or possibly something utterly reasonable but not practical to most people. That said, to me it feels like wearing a seatbelt or a ski helmet. I can't imagine anyone being at the beach or pool without a full cover over their torso in addition to sunscreen. This "launder-in" sunscreen stuff sounds like hokum.

Melanoma, in general, just kills you. In hideous, awful ways. Their is no such thing as being "too careful".
posted by docpops at 10:37 AM on May 19 [1 favorite]

edd: See how quickly the solar spectrum drops off at...

Thanks for the chart, it's good news from a sunburn perspective. Hate to be pedantic, but that's actually only how UV-B drops off; visible light is away off the right-hand edge.
posted by Western Infidels at 10:40 AM on May 19

Okay, let's get this straight. Obama is continuing the Bush administration policy of allowing a known carcinogen (sunlight) to be deposited in our atmosphere by an unregulated extraterrestrial nuclear powered fusion reactor? EPA! EPA!
posted by dances_with_sneetches at 10:42 AM on May 19

How about body soap with sunscreen built in?
could protect more than that traditionally covered by clothing,
and has the same advantage of building the protection into the routine rather than an often inconveniently timed application
(i can't count the number of times i've known people to willfully get a nasty sun burn because it was a pain in the ass to put on sun screen)

although - most products seem to be lower level protection (~ SPF 10) so you'll still need more for a full day at the beach
And it also raises the questions of prolonged exposure to sunscreening chemicals
(although I tend to think the very real connection between sun exposure and skin cancer trumps a "those awful awful chemicals" argument)
posted by sloe at 10:57 AM on May 19

Many but not all home laundry detergents in the US contain stilbenes as fluorescent brighteners. Some people prefer to avoid optical brighteners, either due to distrust of unnecessary chemicals or, interestingly, for safety reasons in combat; as a result, there are many detergents that contain no fluorescent brighteners. Any detergent that is not on the list is likely to contain them.

As far as I've been able to find, Tinosorb FD is used in an Australian laundry detergent, but not in US laundry detergents. While Tinosorb FD is claimed by the manufacturer to be superior, the manufacturer does not give details to support this claim. Various patents describe Tinosorb FD as being more expensive than other brighteners, but it's not clear whether it's a better UV blocker. It does take less time and trouble than washing the kids' new clothes ten times before going on vacation.
posted by Ery at 11:01 AM on May 19

I wear a long sleeve grey UV rashguard that I use for surfing anytime I'm at the pool. Being older, and thus totally out of touch with normal sartorial convention anyway, I'm not sure if what I'm doing is regarded as hideous, comical, sad, or possibly something utterly reasonable but not practical to most people.

It's very common for parents to dress their kids in pretty extensively covering swimwear, some of which looks an awful lot like that "modest" swimwear that made the LOLXTIAN rounds a while back. Big hats, sunglasses, and long sleeves and long shorts are de rigeur at the public pools where I live. For kids, at least, although I see more and more adults doing it too.
posted by padraigin at 11:11 AM on May 19

As somebody with 15 stitches on a forearm where the doc scooped out some basal cell carcinoma last week (next week: same thing, other arm) -- I'd just like to say: Wear Sunscreen.

Thanks a fuckload, great-grandma!

Meh, that's what the alcholism is for!

Thanks dad!
posted by Pollomacho at 11:39 AM on May 19

It amazes me that I can get a speedo which will allow me to get a junk-burn but can't find a tan-thru rash gaurd. The generic stuff sold next to coppertone sport has held up great through several sets before but even then as a pale-chested Scot I'm getting a pretty great farmer-base-tan going :^(
posted by mcrandello at 2:16 PM on May 19

Another pale part-Scot here, and I just sat and did a crossword puzzle in the sun, with no sun block at all. So there. I will achieve beigeness this year, dammit. Or at least neutralize the blue.
posted by bink at 2:23 PM on May 19

I never knew what the proper name for those close-fitting shirts I'd seen people wearing on the beach was: rashguards. Fascinating. They look like a pretty handy piece of clothing, actually.

I'd been looking for a long-sleeved shirt for sun protection purposes that wasn't also hot, mostly to wear while sailing. That looks like the perfect solution.
posted by Kadin2048 at 2:30 PM on May 19

" Hate to be pedantic, but that's actually only how UV-B drops off; visible light is away off the right-hand edge."
I was only pointing out that the shortest wavelength UV is blocked by the atmosphere. I wasn't using it to make any points about visible light, or even the UV nearest the visible range.
posted by edd at 2:56 PM on May 19

I call BS on the "normal clothing doesn't protect you well from the sun" concept. I've heard this other places as well, and I just don't get it.

I lived for years in south Florida, and spent way too much time out in the sun. You don't get a burn under a normal, everyday t-shirt. And I'm an average-to-pale white guy.
posted by jeff-o-matic at 3:12 PM on May 19

At Palmyra in Syria there used to be a trinket vendor who was one of those ocasionally seen pale skinned, red-headed middle easterners. I don't know how many of you have been to Palmyra, but I'm sure plenty around here have been to the Iraqi desert next door or Phoenix. Now think of being a pale redheaded guy who's only volition was standing in the sun all day for the chance to shove shiny crap at tourists as they decended their tour buses.

In his case clothes weren't helping too much.
posted by Pollomacho at 8:05 PM on May 19

I second the BS callout on the claim a new shirt has an SPF of 5.
I can accept that wet clothing may allow extra UV through, but I can sit at the cricket all day slathering on SPF30 cream on my pale legs and arms and still occasionally get a bit burnt, yet I have never had any sunburn through your average white t-shirt.
I have heard normal shirts described as SPF50+ in our government information advertisements, which suggested a shirt beats sunscreen.
Without any treatment, normal summer clothing is effectively sun-proof.
If you want clothes to wear swimming/surfing that may be a different story.
posted by bystander at 10:24 PM on May 19

although - most products seem to be lower level protection (~ SPF 10) so you'll still need more for a full day at the beach
And it also raises the questions of prolonged exposure to sunscreening chemicals
(although I tend to think the very real connection between sun exposure and skin cancer trumps a "those awful awful chemicals" argument)

One thing about SPF, it's not a linear scale. The SPF of a sunscreen measures how much longer a fully protected person takes to burn. So if you normally take 10 minutes to burn, with SPF 30 you'll take 300 minutes (5 hours).
SPF 30 blocks 96.7%, SPF 100 (which is ridiculous) blocks 99% of UVB rays which are the ones that cause sunburn.
UV-A does not cause sunburn, but it does contribute to skin cancer risk, not all sunscreens block UV-A effectively and SPF does not measure how well UV-A is blocked, so look for a sunscreen that is labelled as blocking both.

Most people do not apply it thickly enough (as noted above, protection falls of as the root of the amount applied - Apply half of what you should, get only a quarter the protection)
Nor do they re-apply it often enough, even water resistant sunscreens need frequent re-application if you're immersed in the water especially if engaging in vigorous activity.
posted by atrazine at 11:12 PM on May 19 [1 favorite]