Ombre hair really came into style in 2010, and it's still very fashionable. It is very easy to achieve an ombre look on natural, virgin hair, but still possible to do on previously dyed hair.
1.) How To Get Ombre Hair On Natural, Virgin Blonde to Light Brown Hair
This is, by far, the easiest way to do it. Use bleach, or a high lift Level 10 blonde shade, like L'Oreal Excellence 02 Extra Light Natural Blonde. and leave on your ends ONLY. Check regularly to see how the color is coming along. If it doesn't lighten enough, deep condition and then go again, either later that day or a few days later, if you want to give your hair a rest.
2.) How to Get Ombre Hair on Natural, Virgin Light Brown to Black Hair
It's a little more difficult to lighten dark hair than it is to lighten blonde hair, but it's definitely still doable. You can use bleach on your ends, but you run the risk of your hair turning orange or there being too big of a contrast. If you choose to use bleach, check very regularly to make sure the color looks good. If you'd rather use something more gentle, use a high lift brown or red dye, like Garnier Nutrisse Ultra Color Ultra Intense Red for Darker Hair Permanent Color, R3 Light Intense Auburn. Garnier Nutrisse Golden Brown B3 (Cafe Con Leche). or L'Oreal Preference Les True Brunettes UL 61 Ultra Light Ash Brown.
3.) How to Get Ombre Hair on Dyed/Colored Blonde to Light Brown Hair
If your hair is colored and it's light brown to blonde, it is probably more delicate. Therefore, you are
going to need to do a protein treatment before starting the ombre process. You are also going to need to use bleach, as a high lift dye probably won't give you the desired lightness. Put the bleach on the ends of your hair. Since your hair might be more porous, it will soak up the bleach more quickly, so make sure you really keep an eye on it so that you know how long it's been on. If the bleach winds up making your hair too orange, which is possible on dyed hair, use a demi-permanent ash toned color to dye over the bleach, which will tone down the orange.
4.) How to get Ombre Hair on Dyed/Colored Light Brown to Black Hair
If your hair is colored dark, this will be the hardest. You will need to use bleach, not high lift color, and you run the risk of damaging your hair, so use a protein treatment before hand. Put bleach on your ends and keep a close eye on them to make sure it is not going too light, too quickly. If your hair is black, the bleach will have to stay on for a longer amount of time. It's possible that in the end, the bleach will come out far too orange or yellow. In this case, your best bet is to deep condition and then use a demi-permanent color in either a deep red tone or an ash toned demi color. (Red will make the orange more like a mahogany, and ash tones will make the orange more neutral). If you really want to get creative, use an unnatural blue or pink from the Manic Panic line on the bleached ends.