RE: How much of water needed to dilute the color for the ends?
Once you mix color and developer and apply to the grays(roots), the remaining mixture may be diluted by half with water for the last 5-10 minutes of processing time. This color developer mixture may not be used at a later date. Once the color and developer are mixed, it must be used within the 40-45 minutes after mixing, or it must be discarded.