So which brand stays on best ? (green / blue)

It is different for everyone(dependent on hair structure/porosity/etc.) but both Pravana and Punky Colour last ages and ages in my hair.  Even with forced fading they hold on pretty strong.

I personally really like SFX.  Their blue velvet lasted a month on my hair--and it only started to fade down because I had to force fade it.  That was on processed hair, so might be different on unprocessed hair, but still, they last ages.  The reds I use also tend to last at least six weeks, but you asked specificially about blues/greens, and the only blue of theirs I've used is blue velvet 🙂

One thing I'll ask, do you wash your hair in ways to stop the colours fading? I know you say once a week, but what shampoo are you using? How long do you leave the dye on for? Do you use a little dye in your conditioner when you wash?

Blue and green are often the colours hardest to stay bright.

I find that normal manic panic dyes last longer in my hair than the amplified.
Splat is awful. It lasted two washes and it comes out when i sweat which i never get with other brands.

It is different for everybody, your best shot is Blue Velvet or Pravana I think. Has anyone tried Pravana on unprocessed hair?

I am currently testing out the blue/green spectrum, Adore Indigo lasted the longest on me, more then a month before any fading was noticeable. I washed my hair 2-3 times a week with a sulphate shampoo. But Adore does not stick at all on unprocessed hair, not sure if this is the case with Pravana.

From what I've read Adore and Pravana have a different way of depositing the color blue then other dyes ( http://www.hairdyeforum.com/index.php?topic=12313.msg142961#msg142961 ), so it stays in the hair longer/it's harder to remove.

I have only ever used Splat on processed hair and it is horrible- but my blonde haired coworker says it's the only dye that lasts for her (she doesn't process her hair).

Pravana is the same problem as K-pak and stuff : salon brands that are very hard to find unless I agree to pay high shipping fees ... I'll have to stay with brands sold at beeunique I guess, I'll try the other ones , SFX, adore ... well I still have quite a bit of Manic Panic, so maybe SFX will be back in stock by then !

Janineb : I try to do my best for the longer lasting colour possible :
- I keep the dye on for 4 hours (yes, 4 hours 😀 , I know it may be overkill ...)
- then rinse with lukewarm to cold water, condition the lengths (where there is no dye) but not the dyed part since I feel even conditionner makes it bleed, then do a vinegar rinse - which I am not sure is a good idea since this last rinse's water comes out more colored than the previous, without vinegar one ... but I read everywhere you have to rinse with vinegar.
- I CO-wash mainly (except before dyeing of course), always end with a vinegar rinse. And all steps = lukewarm to cold water.
- I use no heat whatsoever - I have very long hair so my care regimen is mainly based on the "first do no harm" concept ^^

Do you see any flaw there ? What could I do more ? Maybe drop the vinegar rince for the dyed part ?

No, that all looks pretty good. Just checking, though I'm sure you know this, you shampoo rather than co wash before dying right?

Yes I do, using regular shampoo, nothing nourishing or whatnot, to strip out all of the sebum.

Maybe try leaving the dye on over night next time then? I don't think that'll help much though, but worth a try!

Yeah I could try, before going green I was doing a 2-step henna-indigo involving overnight henna + 4 hours indigo, I'm not exactly pleased to sleep with stuff on my head but if it's what it takes ... will have to try.

From what I've read Adore and Pravana have a different way of depositing the color blue then other dyes ( http://www.hairdyeforum.com/index.php?topic=12313.msg142961#msg142961 ), so it stays in the hair longer/it's harder to remove.

That was a very interesting read, more to think about ... more reasons to find a way to get my hands on some Pravana !
I think lots of people here are from Europe, right ? Should someone know of a supplier that would ship (Pravana, or Joico vero k-pak) to european countries, please please tell me !

Have you tried pre softening your hair? You just put 10-20 vol on it, put a cap over it, heat it up for 10-20 minutes, rinse it out, then apply the dye. After you apply it you can put a cap on it and heat it up for 10-20 minutes- it makes a big difference for my resistant hair. Then leave the cap on and leave the dye on as you normally would.

Joico is really good, it's a shame you can't get it over there 🙁 Pravana is good, but I see you can't get that either. I think Special Effects would be your best bet or Punky Color. Some of the SFX colors are basically permanent on processed hair. I would definitely give it a try, I personally think SFX is the best semi brand out there. I don't know if it is available over there, but Ion's blues are nearly impossible to remove so it may be worth looking into, I'm sure it would last longer on your hair

I know a little bit of processing would help ... but that's a definite no-no for me, as I'm not willing to sacrifice future length for colour, even minimal damage I can't afford if I want to keep my length ! May be I will come to it, but not now for sure !

No idea about the Ion ... will have to look into this one, too.  Yeah I so LOVED my Joico, it was a gift from a student of mine who had bought it while on holiday in Canada for fun but never had the gut to bleach her mediterranean-black hair so she gave it to me. It was really great, so easy to apply dyeing almost didn't feel like a chore, great staying power ... then I looked around the web to find it and no way :/

Wow, Joico do alternative colors, I have to try them! You can find most dyes on ebay, but can never be too sure about how legit they are. Also the shipping is almost as much as the dye itself, at least for my country. I have found that SFX is worth the pretty penny.

You can try a natron wash - 1 tablespoon of baking soda in lukewarm water, stir until it's fully dissolved, pour it over your roots, massage a bit and rinse it. I found it helps a bit, my roots always seem to be in too good condition even after bleaching they don't take dye as well as the rest of my hair, and I don't even have struggles with gray hair yet.

Do you apply on dry hair, I don't get an uniform application on wet hair, the dryer the better.