How to tell if a fabric is UPF 50+ (without fancy equipment)

I have bought sun hoodie from AliExpress calming to be UPF50+.
How can I check at home it is really protecting against sun damages?

That’s an interesting question.

Need something like a light exposure meter but with the sensor sensitive in the UV region. Found some pricey ones online.

The CCD sensor elements are available if someone wants to build their own device. For example, UV photodiodes

These Might Help . Try putting them inside the hoodie, and step outside to see if it changes color.


Thanks It may be a great test.
Unfortunately, shipping price to my location is more expensive than the card itself. Actually, cards + shipping is more expensive than the shirt :(

spf 50 means 1/50 of the light gets through

for a camera that is log 50/ log 2 which is about 5.6 f/stops

Stumbled upon THIS thread. Call for Big Clive to the resque.

Place two bananas on an outside table, one under hoodie, and one exposed to the sun. Maybe you notice a difference between them at the end of the day. If not: bon appetit.

If you notice a difference: the next step is to buy some calibrated bananas on Ali.

Make a small tent of part of it and put some UV glue/epoxy under it, then put it in the sun? Not calibrated but if effective it should not kick for a good while……I’d guess.

You want to check if your new clothing is really protective against sun damage? Without spending anything on fancy equipement?

You could just put it on and go sunbathe for a couple hours. If you get sunburn and skin cancer below the fabric, you’ll know it was not actually UPF 50+. :laughing:

how about you just wear it and see if you get a tan or skin irritation after spending time outside?

i am honestly completely surprised that this is a class of clothing that even exists. special clothes for sun protection? really?

my skin is always lily white under areas that are protected by normal clothing. do your regular clothes you already have seriously not protect you to your satisfaction?

I don’t know how scientific this is, but I have tested sunglasses and visors by shining my UV Convoy S2+ through them. Usually I point it at the dogs bed, or clean load of white laundry so there something to flouresce. Then I slide the sunglasses/face visor over the torch, and if the flourescing stops, I figure it’s blocking UV.

I have one of these almost ready to arrive, and I plan to test it like that.



That is clever I will try this


does it normally it cure using sunlight ?





Apparently you can get skin cancer while wearing normal closes, even without getting burned

I’ve had a shite day today.
Henk4U2, you have given me a great laugh. I need a calibrated banana!

On a serious note, I work outside most of the day, in Qld, Aus.
Hat, long sleeves, long pants and gloves (maybe) - all workwear.
I don’t see much workwear clothing being sold as UV50+.
Think it’s a bit of marketing/bullshite.

Just hold the material up to the sun and try looking at the sun through it.

Thin and/or open-weave material will show the sun through it. Thicker and/or closed-weave material will be more opaque.

Eg, an umbrella (even black) has sheer material and you can see the sun through it. A hoodie or sweatshirt, not so much.

So take a lumenometer (or phone with app, etc.) and record the light level unshielded, and with the material covering the sensor. If less than 1/50th the value, it’s at least SPF50.

Yes, UV cure glue, cures……rapidly (less than a minute, starts in seconds) in direct sunlight.

Do a search, there are LOTS. The kits you get to fix windshield cracks are UV cure epoxy.