Help! How Do I Get Control of Fluorescent Colors?

Fluorescent colors behave fundamentally differently than "ordinary" solid colors. They do not only reflect light but convert part of the UV radiation into visible light. This makes them spectacular in application — and challenging in color measurement, color formulation, and quality control.

The following points of attention will help you gain more control of fluorescent colors in production and assessment.

1. Understand the Behavior of Fluorescent Pigments

Fluorescent pigments:

• Absorb UV light and short-wave visible light
• Emit extra visible light (emission)
• Therefore appear "lighter" and more intense than conventional pigments

Use only high-quality fluorescent pigments that have been developed for your application (coatings, plastics, ink, textiles, etc.). The choice of pigment has great influence on lifespan, intensity, and discoloration behavior.

2. Always Look Under the Right Light Conditions

You never assess fluorescent colors only under standard office lighting.

Pay attention to:

• Always also assess under UV-rich lighting (blacklight or daylight simulation with UV component)
• Compare the same color under:
  • Daylight / D65
  • Indoor lighting (e.g., fluorescent/LED)
  • UV light (if relevant for the application)

Only then will you see how the color will behave in practice.

3. Use Color Measurement Equipment Consciously

With color meters, you can also quantify fluorescent colors, but:

• Not every instrument is suitable for properly describing fluorescence
• The UV component of the light source and the instrument settings are crucial
• Always measure according to a fixed measurement protocol (geometry, UV settings, calibration)

Record at minimum:

• Chosen light source(s)
• Observer angle (2° / 10°)
• Measurement geometry (e.g., 45/0 or d/8)

Consistency is more important than one "perfect" number.

4. Formulate Specifically for Fluorescent Systems

Create separate color recipes for fluorescent colors:

• Always note exact pigment types and dosages
• Describe mixing order and mixing time
• Take into account any combination of fluorescent and non-fluorescent pigments

Document everything so that a future batch can be reproduced under the same conditions.

5. Test on the Right Substrate

Fluorescent colors react strongly to:

• Substrate color (white, transparent, colored)
• Gloss level
• Layer thickness

Therefore, always test on the actual material or a representative test panel. A color that looks good on a white card can appear completely different on a colored or transparent substrate.

6. Pay Attention to Combinations of Fluorescent Colors

When multiple fluorescent colors are used next to or over each other:

• The mutual interaction can change the perception
• One color can visually dominate the other
• Unwanted color shifts can occur under other light sources

Therefore, always check important combinations visually and, if possible, instrumentally.

7. Think From the Usage Situation

Determine in advance:

• Where the product will be used (indoor/outdoor, daylight/artificial light)
• When fluorescence is essential (e.g., emergency signaling, promotion, fashion)
• How long the effect must last (lifespan, color fastness, UV exposure)

Adapt your pigment choice, binder, and quality criteria to these practical conditions.

8. Document Your Process and Monitor Your Equipment

For control of fluorescent colors, process discipline is essential:

• Keep a logbook of:
  • Pigment ratios
  • Mixing procedures
  • Light conditions during assessment
  • Measurement settings and measured values
• Calibrate color meters and mixing equipment regularly
• Work with fixed reference samples (master standards) and store these under controlled conditions

This way, you can trace, analyze, and specifically correct deviations.

9. Don't Hesitate to Bring in Expertise

Are you new to working with fluorescent colors, or are you stuck with:

• Large batch differences,
• Complaints about visible color differences,
• Problems in specific light situations?

Then consult a specialist in color measurement and color technology or your pigment supplier. A brief analysis often prevents much rejection and discussion.

Want to Delve Deeper into Color Measurement and Color Technology?

In the Applied Color Technology course, we go deeper into:

• Color measurement (including special cases such as fluorescence),
• Tolerances and ΔE,
• Color formulation and process control,
• Practical cases from industry, coatings, and plastics.

👉 More information and current dates can be found at kleurenschool.nl.

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Questions about fluorescent colors or color measurement? Contact us via info@kleurinstituut.nl or call +31 (0)70 364 98 02.