What is L'Oréal Dia Color?
L'Oréal Dia Color is a demi-permanent hair color that uses acidic technology to deliver a high-gloss finish. It’s a great option for toning, blending grays, or refreshing existing color—offering up to 70% gray coverage. I really like how gentle the formula is, making it perfect for anyone who wants a low-commitment color that still gives plenty of shine and a soft, natural-looking regrowth.
Why choose L'Oréal Dia color;
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Ammonia-Free Formula: Gentler on hair and scalp.
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Acidic pH Technology: Seals the cuticle for superior gloss colour.
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Customizable Results: From tone-on-tone colour matching to gray blending.
How to Mix L’Oréal Dia Color the Right Way

Getting the mix right is key to achieving beautiful, even color with L’Oréal Dia Color. The standard mixing ratio is:
1:1.5 – which means for every 1 part of Dia Color, you’ll need 1.5 parts of Diactivateur Developer.
For example:
If you're using 50g of Dia Color, mix it with 75ml of Diactivateur.
This ratio gives the perfect consistency for smooth application, even saturation, and long-lasting results.
Which Diactivateur Developer Should You Use?
L’Oréal offers three Diactivateur options, each designed to give different levels of deposit and coverage. Choosing the right one depends on the result you're aiming for and the condition of your hair.
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Best for toning, adding shine, or refreshing hair colour
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Works beautifully on pre-lightened hair or natural bases
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Very gentle—ideal when you want subtle results
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Good for blending up to 30% gray hair
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Gives soft tone-on-tone results with a bit more dimension
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Offers up to 70% gray coverage
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Great when you need richer tones and stronger deposit
👉 My advice? Always match the developer to the hair’s needs and the desired result. The right combo makes all the difference.
Step-by-Step: How to Mix and Apply L'Oréal Dia Color
If you want consistently beautiful results with L'Oréal Dia Color, following the right steps really matters. Here's how I do it:
What You’ll Need Before You Start
Before diving into mixing and applying L’Oréal Dia Color, make sure you’ve got everything set up. Here’s a quick checklist to keep things smooth and stress-free:
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Suitable disposable gloves – Always wear gloves to protect your hands.
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Non-metallic mixing bowl – Metal can react with hair color, so stick to plastic or glass.
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Color brush – For precise application and even coverage.
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Measuring scale or color scoop – To get the mixing ratio just right.
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L’Oréal Dia Color shade of choice – 1 tube based on your hair goals.
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L’Oréal Diactivateur Developer – Choose between 6 Vol, 9 Vol, or 15 Vol depending on the result you're after.
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Towels or a cape – To protect your clothing.
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Timer – Helps you keep track of processing time.
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Clips – For sectioning the hair neatly during application.
Step 1: Prep Everything
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Wear suitable disposable gloves for safety.
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Grab a clean, non-metallic bowl and a color brush.
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Choose the right shade based on your hair and goals.
Step 2: Mix the Color
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Measure 1 part Dia Color into the bowl.
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Add 1.5 parts Diactivateur Developer (choose the one based on your desired result).
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Mix well until the texture is smooth and creamy—this helps with even application.
Step 3: Apply the Color
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Work preferably on dry, unwashed hair or towel-dried hair.
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Use a brush for precise application, making sure the product is evenly distributed from roots to ends.
Development Time
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Toning or Refreshing: 5–10 minutes for a soft tone boost
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Gray Blending: 20 minutes for up to 70% gray coverage
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Deep Toning or Correction: 20 minutes to refine or correct color
📝 Tip: Keep an eye on the hair during processing to avoid over-toning.
Aftercare Tips
Rinsing
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Once the time is up, emulsify the color with warm water and rinse hair thoroughly.
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Skip the shampoo unless absolutely needed. Instead, use a color-safe conditioner or post-color treatment.
Maintaining hair vibrancy
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I recommend sulfate-free shampoo and other color-safe products.
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It's encouraged to minimize heat styling and always use a heat protectant if you do.
Common Mixing Scenarios

Whether you’re refreshing old hair colour or blending in those first grays, L’Oréal Dia demi-permanent color is super versatile. Here are a few go-to scenarios and how to approach them:
1. Refreshing Faded Lengths
If you have dull hair, this is a quick and gentle way to bring it back to life.
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Use 6 Vol Diactivateur for a soft, gloss colour
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Apply to mid-lengths and ends
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Let it develop for 5–10 minutes to enhance hair vibrancy
2. Blending First Grays
Perfect for those just starting to see gray hair and wanting a soft, natural blend without full coverage.
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Choose 9 Vol or 15 Vol Diactivateur, depending on the percentage of gray and desired depth
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Focus on the roots where gray is most visible
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Let it process for up to 20 minutes to achieve a seamless, low-commitment blend
3. Creating Soft Pastel Tones
Ideal for those who love delicate shades like lavender, rose, or icy blue.
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Start by pre-lightening the hair to a level 9–10 for the color to show properly
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Mix your chosen pastel Dia Color shade with 6 Vol Developer
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Apply and process for around 5 minutes—these shades are delicate and develop quickly!
💡 Pro Tip: Always monitor the hair during the processing—timing and developer choice can make a huge difference in the final result.
Tips for the Best Hair Colour Results
Want flawless, shiny color every time? These small essential steps can make a big difference:
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Do a strand test first – It’s the best way to test how the shades will turn out.
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Clarify if needed – If the hair has a lot of buildup from products or oils, use a clarifying shampoo to help the color absorb evenly.
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Be careful with overlapping – Try not to apply color over previously colored sections unless you’re refreshing; this helps keep the hair healthy and prevents unnecessary damage.
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Adjust your timing – Porous hair may grab color faster, so always consider the hair’s condition and how intense you want the colour to be.
✨ A little extra attention goes a long way when it comes to achieving salon-quality results with Dia Color.
Summary
Getting the most out of L’Oréal Dia Demi Permanent Colour really comes down to mixing and applying it the right way. When you understand the correct ratios, pick the right developer, and development time, the results truly speak for themselves—vibrant, glossy, and long-lasting colour. Thanks to its ammonia-free formula, it’s also a great option for those who want something gentler but still beautiful and high-impact. It’s no surprise Dia Colour remains a go-to for pros who care about both results and hair health.
Frequently Asked Questions
Can I use Dia Color on previously colored hair?
Absolutely! L’Oréal Dia Color is actually ideal for refreshing faded lengths, enhancing tone, or adding shine to previously colored hair. Just be mindful not to overlap too much on already saturated areas—especially if you're working with porous hair, to keep it healthy and vibrant.
How long does Dia Color last?
Dia Color typically lasts around 6 weeks, depending on how often you wash your locks and the products you use. To maintain its vibrancy, opt for sulfate-free shampoos and minimize heat styling.
What’s the difference between Dia Color and Dia Richesse?
Dia Color is formulated for covering white hair and providing depth, resulting in a solid shade. Meanwhile, Dia Richesse is lighter, perfect for toning and adding gloss, offering a natural, shiny finish with softer results.
Can I mix Dia Color with other brands?
It's recommended to use L’Oréal’s Diactivateur Developer for optimal results. Mixing with other brands can alter the consistency and effectiveness, so sticking with recommended products ensures the best outcome.
Is Dia Color safe for sensitive scalps?
Yes, Dia Color is ammonia-free, which makes it gentle on most scalp types, including sensitive ones. It’s a great option for clients looking for vibrant color without the harshness of traditional hair dye.