Many pigment manufacturers claim their products are "100% pure" or "filler-free," but buyers often remain skeptical—especially when the price seems unusually low.
It is natural to wonder whether inexpensive pigments have been diluted with fillers such as calcium carbonate, kaolin, or other inorganic materials. After all, fillers cost significantly less than organic pigments, and adding them can substantially reduce production costs.
So, is there a simple way to determine whether a pigment contains fillers?
Method 1: Ash Content Test
One of the most reliable methods is to measure the ash content.
Accurately weigh a small amount of pigment and place it in a muffle furnace at approximately 800°C. Most organic pigments will decompose completely, leaving only inorganic residue behind.
If the remaining ash exceeds 2–3% and appears white or light-colored, it may indicate the presence of fillers.
However, it is important to note that some pigments naturally contain metallic elements. For example, Phthalocyanine Blue contains copper and will leave colored ash after combustion. Therefore, the pigment chemistry should always be considered when interpreting results.
Method 2: Evaluate Tinting Strength
Prepare a standard color sample using the same dosage of pigment.
If the pigment exhibits noticeably lower tinting strength than previous batches and the color appears pale, grayish, or washed out, filler addition may be a possible cause.
Keep in mind that variations in crystal form or particle size can also affect tinting strength, so this method should be used together with other tests.
Method 3: Sieve Residue Examination
Take approximately 100 grams of pigment and pass it through a 325-mesh sieve.
Examine the retained material carefully. If numerous white particles or powdery residues remain on the sieve, they may not simply be pigment impurities but could indicate the presence of added fillers.
Method 4: Acid Reaction Test
This is one of the simplest and most direct methods.
Add a small amount of pigment to dilute hydrochloric acid.
If visible bubbling occurs due to the release of carbon dioxide gas, the sample likely contains calcium carbonate filler.
The reaction is straightforward and easy to observe.
A Real-World Example
An experienced ink manufacturer once purchased a low-cost yellow pigment that appeared attractive from a pricing perspective.
However, during ink production, the pigment could not be dispersed properly and produced weak color strength. After conducting an ash content test, the residue reached nearly 15%, revealing a significant amount of filler material.
The lesson was clear: the apparent savings quickly disappeared through reduced performance and processing difficulties.
Don't Rely on Price Alone
When purchasing pigments, price should never be the sole consideration.
Rather than relying only on supplier claims, buyers should conduct basic verification tests or request batch-specific ash content reports and quality inspection data.
A supplier willing to provide transparent quality information demonstrates confidence in its products.
At UPBRIGHT CHEMICAL, we are committed to supplying high-quality organic pigments with strict quality control standards.
We stand behind our promise of "Real Pigment, No Fillers." Every production batch undergoes rigorous internal testing, including ash content, sieve residue analysis, and other critical quality evaluations.
For customers who wish to verify product quality independently, samples are always available for testing and evaluation.
Our Application-Focused Organic Pigment Solutions Cover More Than 30 Market Segments:
Plastic Masterbatch
PE Blown Film & Cast Film
PP Nonwoven Fibers
Artificial Grass Yarn
PET Polyester Fiber
PVC Cable Compounds
Low-Smoke Halogen-Free Cable Materials
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EVA Foaming Applications
Rubber Coloring
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Refinish Paints
Coil Coatings
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Container Coatings
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Metal Decoration Coatings
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And many other specialized industries.
Our product portfolio includes:
✔ High Heat Resistant Pigments
✔ High Weather Fastness Pigments
✔ Transparent Grades
✔ Opaque Grades
✔ Halogen-Free Pigments
✔ FDA-Compliant Pigment
