If you are engaged in pigment production and face this challenge — using dyes as raw materials in an alkaline system — this guide is for you.

Many customers plan to manufacture multi-colored pigments with dyes, but because their system is alkaline, the dyes must also remain stable in alkaline conditions. Otherwise, issues such as color deviation, reduced color strength, or precipitation will occur.

As a professional dye supplier offering direct dyes, acid dyes, and basic dyes, we have developed a practical solution to help you make the right choices.

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1. Core Recommendation Logic

The first step is clarifying which dye types are compatible with alkaline systems.

Conclusion: For alkaline pigment systems, basic dyes are the primary choice.

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2. Color-by-Color Recommendations (Basic Dyes)

2.1 Red Series

• Basic Red 14 (Rhodamine B)

  • Shade: Bright red to rose, high vividness.

  • Features: Stable in pH 8–11, good solubility, excellent for high-saturation reds.

  • Use: Combine with Basic Yellow or Basic Blue for orange-reds and magentas.

• Basic Red 51

  • Shade: Reddish-purple.

  • Features: Better migration fastness, suitable for outdoor/weather-resistant pigments.

2.2 Yellow Series

• Basic Yellow 2 (Flavine O)

  • Shade: Bright lemon yellow, high strength.

  • Features: Stable in pH 7–12, cost-effective.

  • Limitation: Light fastness only moderate (grade 3–4). Pair with Basic Yellow 13 for better durability.

• Basic Yellow 13

  • Shade: Golden yellow, warm tone.

  • Features: Better light fastness (grade 4–5), suited for decorative pigments.

2.3 Blue Series

• Basic Blue 9 (Methylene Blue)

  • Shade: Pure sapphire blue.

  • Features: Stable in alkaline systems, excellent mixing ability.

  • Applications: Alone for pure blue; mixed with Yellow to make green, with Red to make purple.

• Basic Blue 54 (Navy Blue)

  • Shade: Dark navy blue.

  • Features: High migration fastness, suitable for darker formulations.

2.4 Green Series

Instead of using rare and expensive green basic dyes, green pigments are best achieved by compounding blue + yellow:

• Grass Green: Blue 9 (1) + Yellow 2 (2)

• Dark Green: Blue 9 (1) + Yellow 13 (1)

• Forest Green: Blue 54 (1) + Yellow 13 (0.5) + small amount of Black

2.5 Black Series

• Basic Black 1 (Aniline Black)

  • Shade: Pure black with strong hiding power.

  • Features: Alkali-resistant, withstands short-term 120°C processing.

  • Note: Excess dosage may cause graying; combine with Blue 54 for deep blackness.

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3. Key Supporting Recommendations

3.1 pH Control (Keep pH 8–10)

• Too high pH (>12): May darken shades (e.g., Basic Red 14).

• Too low pH (<7): Reduces alkaline stability.

• Best practice: Adjust with sodium carbonate or sodium hydroxide; avoid overly strong alkalis that damage dye structure.

3.2 Dispersant Matching

• Basic dyes are cationic → match with cationic dispersants (e.g., CTAB).

• Avoid mixing directly with anionic substances unless compatibility is pre-tested.

3.3 Sample Testing First

Always verify with your own alkaline components:

• Mix 0.1 g dye with 10 g alkaline medium.

• Observe after 24 hours: precipitation, shade change, dispersion uniformity.

• Scale up only after passing tests.

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4. Summary & Customer Guidance

• Core Recommendation: Use basic dyes — Red (14/51), Yellow (2/13), Blue (9/54), Black (1), and mix Blue + Yellow for Green.

• Absolute Exclusion: Acid dyes cannot be used in alkaline pigment production.

• Direct Dyes: Only supplementary in rare cases.

If you have specific shade needs (orange, purple) or special performance requirements (outdoor stability, food-contact grade), we can customize recommendations and provide tailored formulations.