Why do they put a towel on your head when you have highlights?

[Reastie]

I've been googling and I can't find an answer!

I ask because I had my hair coloured yesterday. Only second time I've ever had it highlighted (although regularly get it dyed) and my usual hair dresser/colourist was off so I had a newly qualified person. The newly qualified person didn't put a towel thing over my head like I had last time I had highlights when it was left in my hair and I didn't even realise this until I got home and I wondered if it was an important step as he added more highlights but it doesn't really look like he has looking at it. Thinking about it he did put a towel thing on another woman's hair who had highlights but not mine. He also only left the dye on for 30 mins not 45 because he to so long putting it on there wasn't time to leave it for longer -maybe it was this?

I've had my hair coloured every six weeks for the last 20 years. No ones ever put a towel on my head during the colouring. HTH.

Get my hair highlighted every 8 weeks and never, ever had a towel put on!

A towel? I've never had a towel put on my head!

Never had a towel put on.
You know you can just ask at the time?

Possibly to warm the dye.

Sometimes if it is taking ages for the dye to "take" (I have very resistant hair) they run a hairdryer over the more recent foils, and in previous salons I have always been sat under the heat lamp.

Never had a towel on my head either
Sometimes sat under a sun lamp or left longer. I don't really lie sitting under the lamp with all that foil as I feel like a cooled chicken!!

I've had highlights done approximately a bajillion times and I've never had a towel on my head.

It's the warmth. Makes the dye work faster.

Never a towel here. Sometimes they sit me under a spinning warm thing if there isn't much time but that varies.

I would have asked but it didn't occur to me that it had been forgotten or that it happened last time until I got home. I will ask them next time I go to see what they say.

I've washed my hair now and weirdly the highlights have shown up more obviously so at least I know they worked!

I wonder why some places do the warming and others don't then. My usual hairdresser joked last time if my hair grew too long (I'm growing it) that I might need a bin bag in my head as the towel would be too small!!

Warmth heats the cuticle and it opens letting the colour penetrate.
Most colours need warmth, if it's straight on the head body heat does it.
It makes the process quicker cutting from 40 mins process time to 20.

Never had a towel either! Have had the spinning warm thing, usually when had a full head and it's taken a long time, it speeds the top ones up so they are ready at the same time as the bottom ones that have been on longer