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How to Measure and Control Paint Quality (Viscosity, Color and Gloss)

Do you really know if your paint batch will meet the required specifications for finish, durability and application?
In the demanding process of coatings manufacturing, quality control is not optional—it is the guarantee of performance. Properties such as viscosity, specific weight or color must be continuously verified to ensure that the final product is not only applicable but also delivers the expected result to the customer.

In this technical guide, we will thoroughly analyze the 7 fundamental characteristics you must control in your production process. Discover the methods, units of measurement and key equipment to master paint control and take the quality of your formulation to the next level.

1. Paint Viscosity: Concept, Units and Essential Measurement

Viscosity is defined as the internal resistance of a liquid to flow or be poured. This resistance originates from the friction between the molecules of the fluid. It is essentially the opposite characteristic to fluidity: the greater the fluidity, the lower the viscosity.

The official unit of measurement in the International System (SI) is Pascal-second (Pa·s), although Poise is traditionally used. In the industry, its submultiple, the centipoise (cP), is frequently used, since water has a viscosity of 1.0020 cP at 20 °C (1 cP = 1 mPa·s).

Key Technical Note: Temperature has a dramatic influence on viscosity. Reporting the measurement temperature is mandatory; in the paint industry, it is typically measured at 25 °C.

There are three leading types of devices used to measure paint viscosity:

1.1. Efflux Cups: Ford, Zahn and Gardner (Flow Time)

These devices operate based on “flow time.” They measure the time, in seconds, it takes for a fixed volume of liquid to flow through a calibrated orifice (with different cup numbers). They are fast and easy to use, widely applied in inks and adhesives manufacturing, although they are not recommended for non-Newtonian fluids (whose viscosity varies with applied shear).

1.2. Stormer Viscometer: Measuring Viscosity in Krebs Units (KU)

The Stormer viscometer uses a standardized paddle that rotates when weight is applied. The time required to complete 100 revolutions at a given weight is measured. Results are expressed in Krebs Units (KU), using a reference chart such as ASTM D562.

1.3. Brookfield Viscometer: Rotational Viscosity Measurement (cps)

This system measures viscosity by detecting the torque required to rotate a spindle at constant speed while immersed in the fluid. The reading is given in centipoises (cps).

Attention: For correct measurement, it is crucial to take the reading at the same moment from the beginning of agitation, especially in thixotropic products, whose viscosity can vary with time under shear.

  • Pycnometer: A container with a known volume (e.g., 100 cc) with a cap that includes an overflow. It is filled, weighed with a precision balance, and its known volume allows for very accurate determination of density or specific weight.

  • Graduated cylinder: A calibrated cylinder (e.g., 100 cc) can also be used; although the procedure is similar to the pycnometer, results are less precise.

3. Thixotropy: The Phenomenon of Viscosity Reduction Under Shear

Thixotropy is a fundamental property in paints and many inks. It is the ability of some liquids or gels to decrease their viscosity when shear stress (agitation) is applied.

When the liquid is at rest, particles are randomly oriented, resulting in high viscosity. When agitated, particles align in the direction of flow, allowing them to slide past each other more easily and, therefore, reducing viscosity.

4. Grind Fineness: Dispersion Quality and Its Impact on Finish

Grind fineness is a direct indicator of the degree of dispersion of a paint; that is, the approximate maximum diameter of pigment and filler particles.

This parameter is critical because an inadequate value directly affects:

  • Final color and gloss

  • Corrosion resistance

  • Sedimentation, flocculation and floating problems

The most commonly used instruments to measure grind fineness are grind gauges (grindometers), microscopes with image analysis and laser-based systems.

5. Paint Color: Measurement, Coordinates and Spectrophotometry

Color is a subjective visual sensation, but its measurement must be objective and precise. To define color in the industry, three elements are required: the object, the illuminant and the detector.

Accurate color measurement is carried out using the CIELab system, based on a reflectance curve. This system defines:

  • L: Lightness (more or less white/dark)

  • a and b: Chromaticity (hue and saturation)

The key instrument is the reflectance spectrophotometer, which not only calculates the reflectance curve and coordinates but is essential for color matching, determining the exact amounts of colorant required.

5.1. Tinting Strength: Pigment Coloring Power

Tinting strength is the ability of a pigment or paint to color when mixed with white or another color.

It is measured using the ratio “colored pigment / white pigment” required to achieve a defined standard depth of color. The analysis is performed with the spectrophotometer on film applications of both sample and standard.

5.2. Hiding Power (Opacity): How to Cover the Substrate

Hiding power is the ability of paint to conceal the color of the surface onto which it is applied (opacity).

It depends on the type and percentage of pigment and, fundamentally, on the relationship between the refractive indices of the pigment and the medium. The greater the difference between the indices, the higher the hiding power.

It is measured through the contrast ratio (CR = Rn/Rb), which indicates how close the paint is to full coverage, by comparing reflectance over black-white contrast charts using a spectrophotometer.

6. Gloss: Specular Reflection and Measurement by Angles (Glossmeter)

Gloss or specular reflection is the ability of the paint film to reflect incoming light. The smoother the surface, the higher the gloss. This property depends mainly on the type of resin used.

Gloss is measured with a reflectometer or glossmeter at specific angles depending on the finish:

  • 20°: very glossy surfaces

  • 60°: medium gloss surfaces

  • 85°: matte or near-matte surfaces

Results are expressed as the percentage of light reflected compared to a reference standard, taken as 100.

7. Additional Controls in Paint Manufacturing and Conclusion

Mastering viscosity, color and hiding power is essential, but quality control does not end there. In liquid paint manufacturing, stability, flocculation, flexibility and skin formation must also be analyzed. In dry paint, factors such as film thickness, hardness, adhesion and washability are controlled.

The quality of your final product depends directly on the precision of your control and manufacturing equipment.

At Oliver + Batlle, we hope this technical guide will be extremely useful to you in optimizing your processes. If you are looking for mixing, dispersion or packaging solutions that ensure rigorous compliance with these characteristics, we invite you to consult our industrial machinery catalog or contact our expert team for personalized advice.

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Incorporation of Solids into Oil-Based Systems: Process Development and Pilot Solution for Industrial Formulations

In the technical materials industry—from plastics to specialized coatings—incorporating fine solids into oil-based systems poses a key challenge in terms of mixing and product stability. When working with highly viscous raw materials such as polybutene (PIB) or mineral oils, achieving a homogeneous dispersion, without incorporated air and with guaranteed long-term stability, requires precise process design and equipment adapted to the demands of the product.

In response to this challenge, OLIVER + BATLLE partnered with a client in the industrial plastics sector to co-develop and validate a tailored solution. The goal was to assess the technical feasibility of incorporating up to 4% fumed silica into two different oil-based formulations, while maintaining product homogeneity and ensuring scalability for industrial production.

 

Project Goal: Incorporate Fumed Silica into Oil-Based Carriers

The objective of the project was to develop a mixing process capable of incorporating up to 4% fumed silica into two distinct oil-based matrices:

  • Polybutene 
  • Mineral oil 

Both matrices are characterised by high viscosity, which makes it particularly challenging to disperse low-density solids while avoiding aeration and phase instability.

The key goals were:

  • Confirm the compatibility of OLIVER + BATLLE‘s dispersion systems with the chosen raw materials
  • Verify the efficiency and uniformity of the dispersion process
  • Demonstrate process viability on a pilot scale as a step toward industrial application

Step-by-Step Technical Solution: From Lab Testing to a Custom Pilot Unit

To meet the project requirements, OLIVER + BATLLE proposed a three-phase strategy that combined in-house lab testing, the development of a custom-built pilot mixer, and a full validation of the mixing process.

Phase 1 – Laboratory Trials

The initial testing phase took place in OLIVER + BATLLE‘s technical laboratory using a planetary mixer designed for high-viscosity media.

  • Multiple trials were conducted using different dispersion parameters and dosing sequences.
  • All tests were recorded and shared with the client for remote review.
  • Results exceeded expectations, delivering a homogeneous dispersion with no air entrapment or visible separation.

Phase 2 – Design and Delivery of a Custom Pilot System

Based on the successful lab tests, OLIVER + BATLLE designed and manufactured a bespoke pilot solution:

  • MPVDV-30 planetary mixer, adapted to the rheological requirements of the formulation.
  • Integrated vacuum powder loading system, enabling clean, safe incorporation of solids.
  • Plug & play configuration, compatible with the client’s R&D lab environment.

This pilot system was built to simulate full-scale production conditions while maintaining flexibility and ease of operation.

Phase 3 – Joint Validation (FAT + SAT)

The pilot unit was temporarily installed at OLIVER + BATLLE’s facility to carry out joint validation sessions with the client (FAT and SAT).

  • A total of 8 real product batches were produced during this phase.
  • Dispersion performance, final product quality and vacuum loading efficiency were thoroughly evaluated.
  • The tests confirmed the robustness of the system and its suitability for further scaling.

Project Outcomes: Efficient Solid Dispersion Without Defects

The project successfully met all its defined targets, with the following key outcomes:

  • Full process validation with client raw materials
  • Efficient incorporation of solids without air or visible defects
  • Custom-designed pilot mixer tailored to product viscosity
  • Smooth transition from lab trials to industrial-scale production
  • Client now fully equipped to continue development in-house

Conclusion: A Reliable Mixing Solution for Oil-Based Systems with Fine Solids

This project showcases how a combination of technical expertise, in-house validation and tailored equipment design enables industrial clients to solve complex formulation challenges. The incorporation of fumed silica into high-viscosity oil carriers is not only possible-it can be done efficiently and repeatably with the right process design and dispersion system.

Thanks to this collaboration, the client is now equipped with a validated, reliable solution for continued product development under real operating conditions.

 

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Development and Scale-Up of Paraffin Emulsion via Phase Inversion

1. Brief company description

Oliver + Batlle works in collaboration with a company specializing in the production of emulsifiers (paraffin emulsions), moisturizing agents, and solutions formulated with fats, waxes, and oils for the cosmetics, pharmaceutical, and home care sectors. Its focus is on sustainable innovation and the development of customized products designed to meet the specific needs of each industrial client.

2. Product to be processed

Paraffin-in-water emulsion, produced through a phase inversion process (W/O -> O/W), with 50% resin content.

The process begins with melting and mixing high-viscosity solids and ends with a fluid emulsion after the critical inversion phase. This variation in viscosity requires a custom-designed anchor agitator and heating at temperatures above 150°C.

 

3. Objective

Starting from a consolidated laboratory process for manufacturing this complex emulsion, the need was to scale it up to an industrial level.

The goal was to achieve a stable dispersion of 50% resin via phase inversion, while avoiding foam formation.

The main technical challenge appeared in the pre-inversion stage, where the product is especially viscous and difficult to mix Additionally, temperature control and water feed rate were identified as critical factors for final product stability.

4. O+B SOLUTION

OLIVER + BATLLE proposed a co-development strategy with the customer, using its in-house pilot plant to validate the mixing system design and tailor the equipment to the product’s characteristics.

Phase 1 – Pilot trials

Three pilot trials were carried out on a 150 L Polimix system, configured with a custom anchor (slow shaft) and a high-speed disperser (coaxial configuration).

The trials used thermal oil at over 150 °C to reach the required process temperature.

The goal was to validate the mixing capacity for achieving stable phase inversion.

Results:

  • Phase inversion was successfully achieved.
  • Some stability issues were detected in the batches compared to the target sample, attributed to process parameters (temperature and water flow) rather than the mixing system.
  • Equipment performance was excellent in terms of viscosity handling and behavior under critical conditions.
Phase 2 – Final solution

After confirming the technical feasibility, the customer acquired:

  1. 1 pilot unit VF-11 Special, with custom-designed anchor
  2. 1 thermal oil heater for the VF-11
  3. 1 production unit DPS-6000-OR Special, also equipped with the same custom agitator system and prepared for steam heating

 

 

During the manufacturing phase, the customer maintained access to the O+B pilot lab to continue developing the product, ensuring a smooth transition from pilot to industrial scale.

 

5. Results

  • Validation of the phase inversion process in a simulated industrial environment
  • Custom anchor design tailored to the emulsion’s mixing needs
  • Successful scale-up from laboratory to industrial equipment
  • Reduced technical risk thanks to joint development using O+B’s lab
  • Equipment currently installed and operational at the customer’s plant.

 

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HIGH-CAPACITY REACTOR FOR THE PRODUCTION OF SPECIAL RESINS

1. BRIEF DESCRIPTION OF THE CLIENT

An international textile-sector company with a highly integrated and sustainable insfrastructure, dedicated to the manufacture of high added-value products from recycled fibres and organic raw materials. With benchmark production capacity in its market, its industrial strategy prioritises efficiency, innovation, and the independence of key processes.

2. PRODUCT TO BE PROCESSED

Special resin used as a base component in formulations for technical textile applications.

3. OBJECTIVE

The client aimed to establish its own in-house production unit for this strategic resin, which had previously been purchased from external suppliers, in order to strengthen industrial autonomy and optimise production costs.

4. OLIVER + BATLLE SOLUTION

To address this challenge, Oliver + Batlle designed and implemented:

– 12,000-litre reactor for resin synthesis through monomer reaction, featuring:

  • Three-section half-coil for precise thermal control using steam and cooling water
  • Agitator shaft with two INTERMIG-type blades, Ø1850?mm
  • Semi-anchor Ø1700?mm
  • Construction material: AISI 316L stainless steel
  • Reactor working temperature: up to 150°C
  • Reactor working pressure: absolute vacuum to 3 bar g
  • Half-coil working temperature: up to 200°C
  • Half-coil working pressure: up to 10 bar g
  • 37 kW agitator motor with frequency converter

– Solids loading system using a screw conveyor, with sack and Big Bag unloading stations

– Complete process control system, including supervision of installation and commissioning on site

 

5. RESULTS

The project met the client’s needs with a robust, reliable and hygienic solution, ensuring consistent performance fully aligned with the highest quality standards.

 

 

accessories for the automation

 

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WHITE BASE PRODUCTION UNIT FOR PRINTING INK – PROJECT FOR SAKATA INX

1. COMPANY OVERVIEW

Sakata INX is a Japan-based multinational company and a global leader in the development and manufacture of printing inks.

Its Spanish subsidiary, Sakata INX España, S. A., operates a production facility offering a wide range of high-quality inks for the graphic sector. These products are manufactured using advanced technologies in varnish production and pigment dispersion, ensuring excellent performance and superior print quality.

The company’s commitment to innovation and continuous improvement has led it to modernise its manufacturing processes to meet the high standards of international markets.

2. PRODUCT TO BE PROCESSED

The project focused on optimising the production of a white printing ink, specifically designed for application on plastic packaging films.

This white ink acts as an opaque background layer, playing a key role in the final visual quality by enabling a clear and uniform reproduction of colours printed on top.

Due to its high opacity requirements, the formulation contains a high concentration of titanium dioxide (TiO?) — a pigment known for its covering power, but also for its high density, cost, and difficult handling properties.

3. PROJECT OBJECTIVES

Prior to implementing the new system, the unloading and dispersion of a single Big Bag of TiO? took approximately one hour, creating bottlenecks in the production line.

The client needed to significantly reduce this time without compromising product quality or operational safety.

Oliver + Batlle was tasked with developing a solution capable of:

  • Increasing the speed of TiO? dosing and dispersion.
  • Allowing for continuous, parallel operation to avoid production downtime.
  • Improving handling safety and cleanliness.
  • Maintaining or enhancing final product quality.

4. TECHNICAL SOLUTION IMPLEMENTED BU OLIVER + BATLLE

The solution integrates a high-capacity, safe and efficient powder handling system, a high-performance conical disperser, a pneumatic transfer and filtration group, and two gravimetric filling lines adapted to multiple packaging formats.

Powder handling system

  • Tubular screw conveyor made of carbon steel, with discharge outlet feeding into the disperser.
  • Driven by a 9.2kW motor.
  • Powder handling capacity: up to 13 ?m³/h
  • Three loading points:
    • Two Big Bag inlets, enabling parallel operation (while one bag is being emptied, the next is positioned for uninterrupted feeding)
    • One manual sack inlet, providing  flexibility for smaller batches or special formulations

Dispersion systems

  • POLIMIX DPS-7500-TRC conical disperser, engineered for large-scale, high-demand production
    • Total capacity: 7,500 litres
    • Main motor: 132 kW
    • Two dispersing blades: diameters 675 mm and 450 mm
    • Half-pipe cooling jacket for temperature control
    • Vertical condenser with a 2 m² heat exchange surface

The disperser design ensures effective incorporation of dense pigments and a highly homogeneous mixture. Its cylindro-conical geometry optimises product flow towards the dispersing blades and improves dispersion performance.

Automatic cleaning system

  • Motorised cleaning lance with rotating head
  • 3″ pneumatic pump fitted with particle filter
  • Nominal flow rate: 150 l/min

This system allows rapid and safe cleaning between batches, reducing downtime and avoiding cross-contamination.

Transfer and filtration

  • GBN12/SBF-0102 transfer and filtration unit, pneumatically driven (2″)
  • 31-litre basket filter with 200-micron mesh, ensuring product cleanliness prior to filling

Filling lines

Two gravimetric filling lines cover a wide range of formats:

1.PALLET 1500/G

  • For 200-litre drums and IBCs
  • Equipped with a floor scale rated up to 1,500 kg

2. OB-130

  • For cans up to 30 kg
  • Includes an integrated 30 kg scale

 

 

5. RESULTS ACHIEVED

The implementation of the new solution brought a significant improvement in production performance:

  • Over 60% reduction in TiO? unloading and dispersion time
  • Continuous operation enabled by dual Big Bag inlets, eliminating handling delays
  • Increased powder flow rate, outperforming the previous system
  • Higher productivity and process consistency, without compromising product quality
  • Improved safety and cleanliness, through a closed and automated solution

In summary, the collaboration between Sakata Ink España and Oliver + Batlle has resulted in a robust, high-capacity and efficient installation tailored to the demanding needs of white ink production.

It is a flexible, high-performance solution that ensures top-quality standards in one of the most critical areas of the printing ink manufacturing process.