Covering or blending gray hair even when you are totally gray is not impossible.
Follow the video to see how I decided to use demi permanent hair color and all the considerations that went into making the transition from gray to Brown (Bronde) a reality.
1. Remember what color your natural hair was before it went gray. That plays a big part in making sure you go for the right color family.
Demi permanent can not lighten hair but only darken hair it is a more gentle color depositing product using a 10vol developer only opens up the cuticle of the already messed up cuticle of gray hair VERY Minimally.

Since Gray hair is resistant to color (even permanent color may not take) I pretreated the gray areas of my hair that I felt would be the most resistant to color my front and sides. I used straight 10vol developer on a cotton ball to "soften" the gray to help those areas take the color better.
I also bought a boost product from the Ion Brand to strengthen and moisturize my hair this is added directly to the color once it has been mixed with developer.

My natural hair color is a light to medium brown. On a color scale I fall in the 67 hair range. It has been strongly advised on a number of Ion reviews to go lighter then with a color that matches your pre gray natural hair color.
Also I did not want to use any Ash color So no Golden Ashe Brown or Blonde.
Instead it is recommended to get better gray coverage go with a color that has a "N" with the color #. I chose 8N which is called Light Natural Blonde (Descriptive choice of color words really need to be ignored as this color comes out way more brown)
I "softened" and then colored the resistant grays first then colored the rest of my hair. For 100% gray hair it says to leave on 3040 minutes without heat.

By the time 2025 Minutes had passed I could see the dye becoming really dark on my hair I quickly showered it off. I not only rinsed with luke warm water but I also shampooed with Vunella Bar shampoo and conditioner which is a gentle, vegan and cruelty free bar shampoo vunella.com
My hair came out a very nice shade of brown close to my natural hair color.
It will fade over time after 68 weeks it would need a touch up for sure.
But the color is great it is less damaging to my hair and it left my hair soft, shiny and manageable.

As a side note my undercut haircut over my ears will allow the resistant grays to be cut short with the overlay of dark brown hair covering the gray sides as they will appear sooner then the rest of my hair.