This product is for licensed colorists performing Shades EQ Gloss services — toning, glazing, blending gray, or refreshing faded color tone-on-tone — not for consumers to buy and apply at home. It's the developer half of a two-part system; it has no use on its own, separate from Shades EQ Gloss or Bonder Inside.

It suits clients whose hair needs toning, shine, or gray blending without lift, rather than clients wanting a lighter overall color result, since the formula is specifically built not to lift natural pigment.

The specific reason a colorist reaches for this over a standard developer is that it's formulated to activate Shades EQ Gloss without lifting the hair's natural pigment, at a gentler 2% peroxide concentration and acidic pH that keeps the service conditioning rather than damaging. Redken states that substituting another developer isn't supported, since it's engineered specifically to control Shades EQ Gloss's viscosity and stabilize its tone, depth, and durability.

Mix Shades EQ Processing Solution and Shades EQ Gloss (or Bonder Inside) in equal parts (1:1) in a non-metallic bowl. Apply with a bowl and brush, or from a bottle; the gloss can be diluted with Crystal Clear to lessen intensity or customize a shade. Process at room temperature for 20 minutes, extending to 40 minutes for gray hair. For resistant hair, process 15 minutes under a pre-heated warm dryer with a plastic cap, then remove the cap and let cool for 5 minutes; for resistant gray hair, process 20 minutes under a pre-heated warm dryer, then remove the cap and process an additional 20 minutes at room temperature. Follow with Color Extend Shampoo and Conditioner.

• Mix Processing Solution and Shades EQ Gloss (or Bonder Inside) in a 1:1 ratio in a non-metallic bowl
• Apply with a bowl and brush, or a bottle
• Process 20 minutes at room temperature (up to 40 minutes for gray hair)
• For resistant hair: 15 minutes under a pre-heated warm dryer with a plastic cap, then remove and cool 5 minutes
• For resistant gray hair: 20 minutes under a pre-heated warm dryer, then remove cap and process 20 more minutes at room temperature
• Rinse, then follow with Color Extend Shampoo and Conditioner

Pros:

• Low, 2% peroxide concentration and acidic pH mean it processes gently and doesn't lift the hair's natural pigment, unlike a standard oxidative color developer
• Purpose-built to work with Shades EQ Gloss specifically, giving predictable, salon-consistent tone and fade
• Supports precise techniques like lowlighting and contouring because the gloss/processing-solution mix behaves as a controllable gel rather than a runny liquid

Cons:

• Only usable together with Shades EQ Gloss or Bonder Inside — it isn't a hair color and does nothing applied on its own
• Not a substitute for a lightening service; because it doesn't lift, it can't correct hair that needs to go lighter, only tone or refresh existing depth
• Requires accurate timing by hair condition (20 minutes standard, up to 40 for gray, different options for resistant hair), so results depend on a colorist's judgment rather than a single fixed process time