By AZoM.com Staff Writers

Topics Covered

Introduction
Pigment Processing at Dr. Kremer
Significance of Size and Shape of Pigment Particle
Comminuting Pigments Using FRITSCH Laboratory Mills
Conclusion
About FRITSCH GmbH – Milling and Sizing

Introduction

The particles of pigments are crucial for enduring works of art. Dr. Kremer from Aichstetten, Bavaria, Germany, is one among the well-recognized experts involved in the manufacture of historical pigments. Dr. Georg Kremer is managing the company founded in 1977. The core business of the company is pigment production based on ancient formulations. FRITSCH laboratory mills are playing a key role in Dr. Kremer’s pigment processing.

Pigment Processing at Dr. Kremer

Figure 1. Kremer’s colors.

At Dr. Kremer’s company, pigments are identically reproduced by comminuting the raw materials such as plants or minerals needed for the recipe. Based on the experience and reports of the users, the quality of the original formulations is much better when compared to the synthetic alternatives. Hence, Kremer’s pigments have received great interest from customers. Kremer’s customer base comprises of restorers and artists from all across the globe. Kremer’s wide range of products is shown in Figure 1.

Significance of Size and Shape of Pigment Particle

The color of a pigment being comminuted is different from that of the primary particle because the transparency is influenced by the crystal size. Hence, the primary particle is responsible for optical perception. As shown in Figure 2, the intensity diminishes towards the finer particles (to the left), i.e., the finest share appears to be the lightest. The shares include 63µm, 63 – 80µm, 80 – 100µm, 100 – 125µm, 125 – 200µm.

Figure 2. Pigment in various particle sizes.

In addition to the size, the shape of the pigment particles is equally important for their optical perception. A round shape is the ideal from an energetic viewpoint to reflect the maximum possible light. Since the light would not be diffracted exactly at the edges on the particle surface, the perception would change with regard to the angular dependence. In addition, it is possible to apply and distribute the round and equally large particles in an exact manner, an added benefit for the user.

Furthermore, the round particles without sharp edges will not damage the tool such as a brush used for this application. Besides having the round shape, the ideal scenario is to have the same size for all particles. This can be achieved by performing the fractioning by means of a FRITSCH Sieve Shaker.

Comminuting Pigments Using FRITSCH Laboratory Mills

Kremer employs different FRITSCH laboratory mills in pigment processing. The coarse pre-comminution is performed using the Jaw Crusher PULVERISETTE 1, which can continuously grind materials in large quantities. The Disk Mill PULVERISETTE 13 is ideal equipment for additional processing.

The selection of the comminution technique is based on the material characteristics of the sample. The Variable-Speed Rotor Mill PULVERISETTE 14 is used for comminuting brittle or fibrous materials. Here, the rough pieces are precisely comminuted by the rotor and the suitable shares are subsequently discharged in to the collection vessel through the sieve.

Figure 3. Dr. Kremer using the Planetary Mill PULVERISETTE 5.

The Mortar Grinder PULVERISETTE 2 and the Planetary Mill PULVERISETTE 5 (Figure 3) are also employed at Kremer’s pigments. The subsequent fractioning is carried out in the Heavy Duty Analytical Sieve Shaker ANALYSETTE 18. The FRITSCH Planetary Ball Mill produces softer particles with a round shape achieved by the circulation inside the grinding bowl and the mechanical strain of the round grinding bodies. Of course, obtaining very narrow grain size distribution is also equally important. Dr. Kremer with the highly durable FRITSCH Instruments is depicted in Figure 4.

Figure 4. Dr. Kremer with the highly durable FRITSCH Instruments.

Conclusion

At Kremer’s pigments, the production of pigments of specific fractions is very often demanded. To achieve this, the grinding conditions at Kremer’s are optimized to obtain the maximum possible desired fraction through avoiding the production of too many large or fine shares.

About FRITSCH GmbH – Milling and Sizing

Fritsch is one of the internationally leading manufacturers of application-oriented laboratory instruments for sample preparation and particle sizing.

Below is a short list of the Fritsch instrument range:

• Mills for crushing, micro-milling, mixing, homogenising of hard-brittle, fibrous, elastic and or soft materials dry or in suspension.
• Instruments for particle size determination according to laser diffraction, dynamic light scattering, and dynamic image analysis and sieving.
• Laboratory Instruments for representative dividing of dry and wet samples, controlled sample feeding, and ultrasonic cleaning.

Laboratories worldwide count on our quality and experience – for the fast industrial application as well as for the especially accurate research technology applications in the industry – and research laboratories.

This information has been sourced, reviewed and adapted from material provided by FRITSCH GmbH – Milling and Sizing.

For more information on this source, please visit FRITSCH GmbH – Milling and Sizing.