Coloring ’clean’ hair

Hey y'all. I've always used Permanent Color, but I'm now using a Demi. I know that it's better to use Permanent color on hair that's not recently washed (presumably to protect the scalp by using it's own oils). Is it necessary for Demi's too? For one thing, I'm not doing my roots/new growth, just my previously colored hair. Secondly, aren't the Demi's less harsh since they don't have ammonia?

So, I'm just wondering.......can I color with Demi on 'clean' hair and still get a desired result?

Thanks y'all. It made more sense to me because of the difference between demi and permanent. My scalp is not sensitive at all! 

eatgreenjello wrote: BTW, do you have luck with demi on top of permanent (I know you're not doing roots)?  When I used to do demi on permanent to refresh the color, it never worked.  Maybe because I have very dark hair to start with?

My hair was extra light platinum for over a year. It took using filler for it to hold any color at all. It's been a gradual process to get my hair back to my natural color which appears to be between an 8N and 9N blonde (I have one or two steps more). Because of my porousity, demi's act more like permanents.

I've added a second pic to my signature that shows the color now (after some more lowlights). It's a little too warm to match my natural color, so the next one I'm using is more ash. The picture is a little misleading due to the lighting.....it's not that golden. You can see the new growth......and this was a couple of weeks ago. In the proper light you can see the neutral/ash tones and a few natural very light blonde highlights in my new growth(which I'm praying aren't grey hairs ).

I'm not sure my boys (bf, my son and his son) are crazy about the darker blonde, but TOUGH! I'm tired of jacking with it.