What is Root Glow?
This particular issue is one which shows up in many guises and often perplexes people – especially with brunette shades. After the hair has been coloured (either immediately or several days later) the roots begin to glow a bright coppery or red colour – especially in sunlight. Many people cannot understand why this is happening and this isn’t an issue that is confined to home colouring, in fact it happens with salon colours too. So the question is why does ‘Root Glow’ happen?
In my years involved with home colour removal, without a doubt the highest examples I see of previous ‘Root Glow’ come from those who have removed an artificial colour and exposed the base which lay underneath. From photographs, I can see the coppery stripes running down the hair from previous colour applications to the roots – where these areas have lightened more so (and kicked up red) than the rest of the hair.
Why does Root Glow happen?
Root Glow happens when hydrogen peroxide enters the hair intermixed with a colourant, on the mid-lengths and ends the peroxide molecule attaches to the colour molecule and a shade is merely deposited. However, the hair directly next to the scalp (eg the roots) is exposed to a higher temperature during the process due to the heat being released from the head. This additional scalp heat will boost the hydrogen peroxide (which is used in the colour developer) and cause the natural hair (at the roots) to begin lightening and ‘kicking up’ natural red tone. On occasions even 3% (10 volume) peroxide (which is very low) can cause some degree of Root Glow, however the standard strength used in colourants is 6% (20 volume) and when this strength is applied to the roots (combined with the scalp heat) the regrowth hair will begin to lighten by around three levels.
Why do I sometimes see Root Glow more so several days after I applied my colour treatment ?
This is due to a something known as 'creeping oxidation'. Peroxide by it's very creation, is basically oxygen infused into water. The process of oxidation (found in hair colouring and lightening) happens because a peroxide will want to revert back to water and the oxygen molecule will seperate from the water molecule. In this process, oxygen molecules begin attaching to other molecules in the hair (such as artificial colour molecules deposited). However, when peroxide is quite a potent strength (20 volume and beyond) it will seek to attach to natural pigment molecules, which causes them to expand and become transparent. This is how 'hair lightening' occurs.
Because peroxide is a volatile formulation, after a colour process (be it colouring, lightening etc) an anti-oxidation treatment needs to be applied to the hair. In fact, these ingredients would be found in the conditioning sachets of the hair colourant products you purchase. However, in some instances (and particularly at the roots which tend to receive less of these conditioning treatments when applied) a process called 'Creeping Oxidation' occurs. Basically, peroxide can stay active within the hair for 48 to 72 hours after application (unless anti oxidized). So if you did not correctly remove and condition that hair at the roots (following your colour), the hair will very slowly continue to lighten, hence why two days after your colour (or often the next morning) you can suddenly see Root Glow.
Why is Root Glow more a problem for Brunettes than Blondes?
In fairer or grey natural bases, Root Glow doesn't tend to happen because there is less depth and red pigment within such hair types, therefore when the root areas lighten – they do so quite cleanly and at the same time accept the (new) artificial colour being added – so the result is a shade as expected which is consistent and evenly deposited.
However, on brunette hair - when the peroxide is accelerated by the scalp heat (when applied as an intermixed colour) the lightening can cause an issue. Hair goes through several stages of lightening from red, to orange to yellow (in cases where people are trying to go blonde). However, if a peroxide is applied to the regrowth of brunette hair and this peroxide is boosted by scalp heat and able to lighten by three levels, what occurs is the hair lifts into the red level. Hair lifted to the red level will not hide well under an artificial hair colourant molecule and most notably will appear to ‘glow’ through that colour molecule – especially when daylight hits it. This glowing can become significantly noticeable if a) a very high peroxide strength was used with the colourant applied or b) you conducted your hair colour on a very warm or hot day (which could cause a level or two more lift than you would normally receive). Likewise, if the creeping oxidation was allowed to occur in the days that followed and the natural hair has continued lightening due to the peroxide molecules remaining in the hair.
How to deal with Root Glow
Root Glow in brunette shades can be a tricky one to deal with because in order to cover it, you need to apply a second peroxide based colour which (in turn) could cause the hair to lighten further and kick up more red.
If you have applied a brunette shade and found your roots have turned a warm bright reddy shade, the best tip I can give you is to purchase a product such as Clairol Root Touch up in a shade only one level darker than the mid-lengths and ends. Take the white cream developer bottle, make a pen mark where the white developer (the peroxide) currently reaches and then pour 50% of the developer away. Next take a bottle of mineral water and carefully top up the developer back to the mark level you created. Close the lid and shake before intermixing as instructed. By diluting the developer you are effectively reducing the strength of the peroxide down to a level whereby only the colour molecule could be deposited and sit within the hair. After you have intermixed the colourant, apply to the roots only and leave to develop. What you should find is the roots take on a slightly darker appearance and the Root Glow is covered.
How to stop Root Glow
As stated, Root Glow tends to appear in naturally darker bases.
· The first rule of applying a hair colourant to these shades it to use a tint bowl and brush and do not simply ‘pour’ the colourant throughout the head. You should apply the colourant with a tint bowl and brush to the mid-lengths and ends first, and then mid-way through development go back to the root areas and apply here. This will give the roots less time to develop and prevent the scalp heat boosting that development to a level whereby the root areas can begin lifting up from the peroxide applied.
· If you are selecting brunette shades and are prone to Root Glow, avoid any shades with red or gold tone in them. These shades will contribute further warmth to possible Root Glow and make the result (at the roots) appear more vibrant.
· If you like standard brunette shades, purchase two colourants from the same brand and of the same base. However, purchase a standard base shade (such as 4.0 or 5.0) for the mid lengths and ends and an ash based shade for the roots (4.1 and 5.1). Using your tint bowl and brush initially apply your base shade (4.0 or 5.0) to your mid-lengths and ends, then midway through development mix up your ash based shade (4.1 or 5.1) with your tint bowl and brush and apply to just the roots. This added ash tone will neutralise any warmth that may appear at the roots. 5 minutes before the end of development, wet a tangle comb and intermix both shades on the head for blending – before rinsing off.
· If you wish to retain a brunette shade, always use an ash based colour (for standard brunettes) and apply just to the roots using a tint bowl and brush and develop for only 15 to 20 minutes. If you like a warmer brunette shade, use a standard base shade (such as 4.0 or 5.0) and work with the natural warmth within the hair.
· If you are a redhead who is getting noticeable Root Glow, try applying a 6.0 or 7.0 colourant to the roots only and giving it a 15 minute development time. This could add a degree of base back into the hair and mute down that glow without covering the tone.
Remember, Root Glow is a common occurance in hair colouring and (in my experience) is significantly increased in warm conditions when the colourant is allowed to sit to full development. Without a doubt the most notable time it happens is when someone has ‘poured’ a colourant from the applicator throughout their hair and gone to full development. Therefore, for new colours always remember to use a tint bowl and brush and apply colour to the roots midway through your development process and not at the beginning.
Always condition the roots well (after removal of the colourant) as this will help prevent creeping oxidation which can occur over 48 to 72 hours and evoke Root Glow after the event.