So I understand there is a drop of paint in the headphone socket that changes colour when the phone has been subject to moisture.

What colour does it turn when its been affected?

And how much moisture does it need?

I believe it turns red, someone correct me if I'm wrong. It normally needs direct contact with water but I do remember some people in humid conditions complaining about the moisture sensors going off without getting wet.

Interesting because I think mine has changed, its a sort of terracota colour. Needless to say it has never had any contact with moisture or humidity

I think half of it changes to red like a semi-circle so the contrast is obvious to the colour it originally was.

Google around and find some pictures of it.

Motorola have had this in their gear for eons - most of my phones (Moto and others) have had it turn red as a result of taking them snow skiing and hiking in high-moisture areas, although they've never been water damaged.

as the other people said, it turns red.

Its more of a sticker though not paint. What i do with most of my phones, is carefully peel it off, then if it needs repairs, stick it back on. on my hiptop its on the sim card try, well it was before i peeled it off.

On the iPhone though, its pretty much impossible to get to...

HTH,
Beau

An apple telephone support agent asked me what colour my headphone jack was...
"It's white. Whats the difference?"
"Red means that the dye has come in contact with water, and then we cannot help you."