Lightening before Henna. Good or bad idea?

You won't get three levels of lift with just peroxide, you would need repeated applications.
The best and safest way to lighten hair is with a really good bleach powder and a low volume peroxide. Something like Matrix light Master, Wella blondor, Schwarzkopf BlondMe or other top quality salon brands will give a lot more lift than generic drugstore bleaches, so you can get the result you want with a much lower volume of peroxide and shorter processing times so will be considerably less damaging.
You can use shampoo to dilute too, making it a bleach bath which can be easier to apply.
Always soak hair in coconut oil prior to bleaching, and do a strand test to determine exactly how long you will need to leave the bleach on for the desired outcome. You will need to note how long you leave the product on so you can get the same amount of lift when you need to touch up the roots.
You will have to apply to mid-lengths first, then ends, then roots last as these will process much quicker (due to heat from the scalp and also because the hair is newer)
If you have a lot of hair (I saw your post on LHC so I am assuming yours is long) don't attempt to do your whole head at once. By the time you have applied it all, the parts you did first will have over processed and you will get a patchy result.
Separate the hair into sections and do each section one at a time. It is vital with bleach that you get it on quickly, as it starts to lift straight away, the longer it is on the lighter your hair will go. So do a manageable amount and concentrate on getting it even, then rinse and move on to the next part.

Thank you for your help, Wicked Pixie.

Okay, so I did a strand test, and I have to say that I'm very pleasantly surprised. 😀

My original hair color is a medium-dark brown, strongly leaning towards dark brown. Well, I guess the easiest way is to simply call it dark brown, period.

What I did was:

20-volume developer (6%) plus blue bleaching powder
Bleach & developer ratio = 1:2
Time: 40 minutes (no heat)

I have attached the before/after photo. What do you guys think?

I'm so satisfied because the result is almost the exact color I am going for! A light coppery, ginger-like color. I might not even need ANY Henna for it, but I'm thinking about putting Henna over this strand to see what it would look like.

Now when applying bleach to the whole head, I don't know if I should do this exact same bleach method I did for the strand, or if I should instead use the bleach bath (bleach wash), where I dilute it with shampoo. And if so, whether I should use 30-volume developer (9%), because the shampoo will make the whole thing weaker.

Not sure about this, so I will think about it in the coming days. If someone can help me out on that one, your comments are much appreciated.

What bleach powder did you use? That is not a huge amount of lift for 20 vol and 40 minutes, if you want to avoid damage a better bleach would get the same result in a shorter time. Or using 10 vol, for 40 minutes.
Try a strand test with the bleach bath mis too, some people find it lifts better due to the sulphates in the shampoo. You can dilute 30 vol to create a 20 vol bleach bath (2 parts developer to one part shampoo)

What bleach powder did you use? That is not a huge amount of lift for 20 vol and 40 minutes, if you want to avoid damage a better bleach would get the same result in a shorter time. Or using 10 vol, for 40 minutes.
Try a strand test with the bleach bath mis too, some people find it lifts better due to the sulphates in the shampoo. You can dilute 30 vol to create a 20 vol bleach bath (2 parts developer to one part shampoo)

My hair has always been very "resistant" to lightening of any form. I used to try regular household peroxide leaving it on for an hour and even heating it up with a hair dryer and there would be no visible lift whatsoever.

The bleach I bought was recommended to me by a stylist and is popular here in Germany. It supposedly has very strong lifting action, and even says so on the product, but as I said, I think my hair is just resistant.

It could also have something to do with the fact that I did a ratio of 1 part bleach and 2 parts developer. Maybe I should've done 1:1.

In any case, I am very satisfied because I never managed to get it to this color just by lightening, which means I might not even need to apply Henna. I used bleach many years ago in a salon over black dyed hair, but it didn't lift even this much.

I will experiment further. 🙂

Bleaching out permanent dye and lifting natural pigment are two very different things.
A 1:2 ratio is fine

Bleaching out permanent dye and lifting natural pigment are two very different things.
A 1:2 ratio is fine

I know what you're saying, but it seems my natural hair just works that way. I don't know how else to explain it. It was always resistant to any kind of lightening or any dye, which is why I'm really pleased with the current results.

In any case, now I used 30 volume (9%) developer and bleach, with the same ratio as in my first attempt.

I got the same results after 30 minutes, and even a bit lighter. So 30-vol definitely saves me ten minutes, which is good I guess.

My next experiment will be the bleach shampoo (bleach wash/bath), but also on a strand. I'm a bit confused what ratio to use here, because I get different information from different sites, but I will just have to pick one out and try it.

Right now my main concern is "hot roots". When doing the bleach wash, how likely is it to cause hot roots? You can't really avoid the roots if you are shampooing your hair according to the instructions on the internet.

And thanks again for all the help. 🙂

No, bleaching natural pigment and dye are completely different. You should never compare them because it's like comparing oranges to plastic apples!

Hot roots isn't so much of a problem with bleach baths as they're not intended to lift much.

If you want to avoid damage, you want the lowest volume peroxide, upping to 30 is a bad idea. 30 vol is the strongest mix you can use, what i would recommend for dark hair when people want light blonde. I would stay away from 30 vol unless you dilute it with shampoo.
Try 10 vol, and leave it on longer, with a good bleach powder that will be enough.
For a bleach bath you control how strong it is by how you mix it. 20vol mixed 50/50 with shampoo will give you a 10 vol bleach bath, its all about the ratio.
The volume of developer is the thing that affects the speed of lightening and the amount of damage, so try and stay low. The damage caused by high volume peroxide is irreparable, so try and avoid it

No, bleaching natural pigment and dye are completely different. You should never compare them because it's like comparing oranges to plastic apples!

Yes, you are correct, and I have finally learned that. However, it seems that even my virgin hair is very resistant to lightening. Not as resistant as dyed hair (of course), but still very resistant. I used to dye my hair with salon dye and 30-vol peroxide many years ago, and it took significantly longer than was stated in the instructions in order to get the needed lift. I don't think it's unheard of.

If you want to avoid damage, you want the lowest volume peroxide, upping to 30 is a bad idea. 30 vol is the strongest mix you can use, what i would recommend for dark hair when people want light blonde. I would stay away from 30 vol unless you dilute it with shampoo.
Try 10 vol, and leave it on longer, with a good bleach powder that will be enough.
For a bleach bath you control how strong it is by how you mix it. 20vol mixed 50/50 with shampoo will give you a 10 vol bleach bath, its all about the ratio.
The volume of developer is the thing that affects the speed of lightening and the amount of damage, so try and stay low. The damage caused by high volume peroxide is irreparable, so try and avoid it

Okay so I experimented further.

My first test was a bleach wash on a strand. Equal parts bleach & 30-vol developer, plus two parts shampoo. The result was not very good. After 40 minutes the lightening was significantly weaker than even my very first experiment with 20-vol regular bleaching. It seems I'd have to leave it on for an hour, and even a bit longer.

My second test was using Henna on some of the strands which lightened the most. The results are very good, because the coppery-red is now even more intense and looks nice.

My third test was putting 20-vol bleach on my inner elbow to see how my skin reacts. I left it on for 40 minutes. No itch, no reaction.

My fourth test was putting 30-vol bleach on my inner elbow, again for 40 minutes. This time there was a very slight itch for a few seconds at the beginning, and then nothing. It left no marks.

So after several experiments I don't know how to proceed. The bleach wash would probably work if I leave it on for a little longer than an hour, but I don't see a point there. If it were 30 or 40 minutes I'd be fine with that, but not longer than an hour. I also notice that dripping of the shampoo might be a problem when doing the whole head. Am I right in this assumption? I'd have to wear safety goggles to prevent getting it in my eyes, lol. 😀

Either way... I see my options as follows:

(a) Regular bleaching, 20 volume for 40-45 minutes.
(b) Regular bleaching, 30 volume for 30-35 minutes.
(c) Bleach wash, but with hair dryer for additional heat to speed up the process.

I guess I could also use a hair dryer for regular 20 volume bleaching, but I'm not sure how damaging this would be.

And again, I've had a terrible experience with hot roots, do I'm not sure how to avoid that.

If you got the desired lift with your first test then i would recommend you stick with that but remember to protect your hair and soak it with coconut oil for a few hours before you bleach to avoid a lot of damage.

Speeding things up is not a good idea, to lift safely you want to go slowly.
I would try 10 or 15 vol, no higher, left on for as long as necessary.
To avoid hot roots you need to strand test a strand on the head. Apply the bleach to the roots last, the strand tests will indicate the right time to do this. (If you apply all over on the strand, time it to when the root area has lifted the desired amount, so if the roots will take 15 mins for example, and the lengths 50, you apply to the roots when the lengths have been processing for 35 mins)
Going for the slow lift with a low vol developer will make it easier to avoid unevenness, plus you will have the option of re-bleaching any darker spots

Speeding things up is not a good idea, to lift safely you want to go slowly.
I would try 10 or 15 vol, no higher, left on for as long as necessary.
To avoid hot roots you need to strand test a strand on the head. Apply the bleach to the roots last, the strand tests will indicate the right time to do this. (If you apply all over on the strand, time it to when the root area has lifted the desired amount, so if the roots will take 15 mins for example, and the lengths 50, you apply to the roots when the lengths have been processing for 35 mins)
Going for the slow lift with a low vol developer will make it easier to avoid unevenness, plus you will have the option of re-bleaching any darker spots

You make some really good points. I think I will go with 20 volume then, because I've tried 10 vol in the past on virgin hair and had very minimal lift after a long time. 15 volume is something I can't find here, so I'd have to order it on the net, and with 20 volume I already achieve the lift I want after 40 minutes.

The thing is... the instructions on my bleach say it should be left on the hair for a maximum 45 minutes. I find this a bit strange though, because if I'm going for a slower lift with 20 volume, I might want to do it 50 minutes (not me, but I'm just using an example).

Now doing a strand test on my head is going to be tricky. Damn. It's going to look weird until I do all of the hair.

Edit/Correction: The bleach instructions say not to leave it more than 45 minutes if using 30 or 40 volume, so it doesn't apply to 20 volume.

No, bleaching natural pigment and dye are completely different. You should never compare them because it's like comparing oranges to plastic apples!

Yes, you are correct, and I have finally learned that. However, it seems that even my virgin hair is very resistant to lightening. Not as resistant as dyed hair (of course), but still very resistant. I used to dye my hair with salon dye and 30-vol peroxide many years ago, and it took significantly longer than was stated in the instructions in order to get the needed lift. I don't think it's unheard of.

It still doesn't take away from the fact you can't compare them. I made no comment on how resistant your hair may or may not be. So when talking about lightening your hair, never even think about it if your hair isn't dyed now. Dyed hair isn't resistant, it just needs to be treated differently 🙂