Wella Koleston Perfect colour chart - help!

[florianb]

I might be wrong, but 6/0 is meant to be used with cooler shades, example 6/0 + 6/1 or 6/2, whereas 6/00 would be used with warm shades, example 6/3 or 6/43.
Both cover 100% grey hair when used correctly.

66/0, the double base series are to be used on resistant, thick hair, which need more pigment.

 

[florianb]

No I mean double digit tones after the / ..like 6/74. Or is a single digit after we the / is better for mixing with natural to cover greys eg 6/7. I know if I use the same number as a double it’s better eg.6/77, 6/66 etc but I wanna try other colours in the future to mix with the intense naturals . Would 6/00 with 6/74 give full block of colour to cover 100% grey?

Yes, 6/00 + 6/74 would provide 100% grey coverage. If you are concerned, you might add 10+ minutes to ensure 100% coverage. I usually give it 45-50 minutes (without heat) for perfect grey coverage.