Precise Color Measurement with Konica Minolta Devices

Konica Minolta Türkiye

In our daily lives, we are surrounded by an endless variety of colours. Although the importance of colour is often underestimated, it actually plays diverse roles in our lives. Since colour evaluation is typically conducted based on individual impression and experience, it is not possible for everyone to control colour correctly using common and standardised methods. Unlike length and weight, there is no physical scale in colour measurement, and this reduces the likelihood that a particular colour will be expressed in the same way by everyone when defining it. We must therefore define colour. What is required for us to perceive the colour of an object is light, the object, and sight. Colour is a perception that arises when light strikes an object and reaches the retina of the eye. Humans can perceive certain wavelengths (360 nm–740 nm) as colour. Many people know that when sunlight is passed through a prism, it creates a colour distribution like a rainbow. This distribution of colours is called a spectrum; separating light into a spectrum is called spectral distribution. The reason the human eye can see the spectrum is that these particular wavelengths stimulate the retina in the human eye, and the region of light that can be seen is referred to as the "visible light region". Moving towards longer wavelengths from the visible light region, we enter the infrared region; moving towards shorter wavelengths, we enter the ultraviolet region. Neither of these regions can be seen by the human eye. The visible light region is only a very small part of this: approximately 380 nm–780 nm. Colour is a matter of perception and subjective interpretation. Even if people look at the same object, they will express the same colour in very different words. Colour perception varies from person to person, and factors such as gender, age, a person's psychological state, and eye sensitivity support this view. Expressing colour verbally is very complex and difficult. A standard method is needed through which colours can be expressed correctly and understood by everyone. In this case, colour perception would proceed much more smoothly, simply, and accurately. By expressing colours numerically, we can perceive colours more easily and accurately. In the history of colour, many methods have been invented to express colour quantitatively. The two most well-known of these methods are the Yxy colour space, discovered in 1931 and based on the XYZ tristimulus values defined by the International Commission on Illumination (CIE), and the L*a*b colour space, discovered in 1976 to provide more uniform colour differences in relation to visual differences. The XYZ tristimulus values and the related Yxy colour space form the basis of existing CIE colour spaces. The concept of XYZ tristimulus values is based on the three components of colour vision theory; the eye has receptors for three primary colours (red, green, blue), and all colours are perceived as mixtures of these three primary colours. The L*a*b colour space (also called CIELAB) is one of the most popular colour spaces for measuring the colour of objects and is widely used in almost all sectors. It is one of the uniform colour spaces defined by the CIE in 1976 to reduce one of the main problems of the original Yxy colour space. Equal distances in the x,y chromaticity diagram do not correspond to equal perceived colour differences. In this colour space, L* represents lightness, and a* and b* are chromatic coordinates. In this scheme, a* and b* indicate colour directions: +a* indicates the red direction, −a* the green direction, +b* the yellow direction, and −b* the blue direction. Using a colour measurement device, results are obtained instantly for each colour space and colour differences. With a colour measurement device, even very small colour differences can be expressed numerically and easily understood. In the L*a*b* colour space, colour difference can be expressed with a single numerical value ΔE*ab, which shows only the magnitude of the colour difference, not the directions in which colours differ. The ΔE*ab formulation is as follows, and colour measurement devices calculate this value automatically. By means of colour measurement devices, we can obtain data on many colour methods. Additionally, viewing an object from multiple angles can make it appear brighter or darker. This is due to the directional characteristics of the object and becomes particularly noticeable in semi-transparent and transparent colours. For correct colour transmission, the viewing angle and the angle of the light source must be fixed. A colour appears different depending on viewing conditions such as viewing angle and illumination angle. When a colourimeter measures the colour of an object, the optical geometry includes the conditions including the angle at which a light beam from a source strikes the object and the angle at which the light is received by a detector. There are different measurement geometries used in various applications such as spherical illumination (d:8, d:0, etc.) and unidirectional illumination (45:0, 0:45, etc.). These should be selected correctly according to the sector and sample used. Additionally, the light source and observation angles used similarly vary according to the sector and should be selected accordingly. When expressing colour numerically and comparing colour differences, the relevant properties of the measured device should be specified. With colour measurement devices, when an appropriate device is selected, colour measurement can be performed on all samples of powder, solid, granule, liquid, and transparent nature using different accessories. In the automotive and automotive supply industry, colour measurements are performed with precise and specialised colour measurement devices. The same applies in the white goods industry, with colour checks continuing from raw materials to the finished product. Additionally, colour checks are performed in the construction sector as well as in the ceramic industry, the metal sector, and the glass sector. Colour measurement applications are also carried out by many companies in construction chemicals and other construction materials. In particular, paint manufacturers use colour measurement devices both to formulate paint colour and to compare colours with standards. In the food sector, colour measurement applications are performed on all products such as meat and meat products, milk and dairy products, biscuits, chocolates, jam, sauce, pasta, flour, fruit juices, and fruits both to produce standard products and for freshness testing. In addition, colour analyses using colour measurement devices are fairly common applications in the food departments of universities. In the cosmetics sector, colour analysis of coloured cosmetic products such as lipstick, nail polish, powder, and foundation is performed according to formulas, while colour analysis of samples in transparent form such as essences is performed from transparency measurement. In some cases, these analyses can also be applied to balance the amounts of substances within the essence. Colour analyses are also performed on personal care products such as soap, shampoo, and shower gel. At the same time, colour measurement devices are also used in cleaning products, another branch of the cosmetics sector, for performance testing of detergents. As mentioned at the beginning, colours are present in all areas of our daily lives. For this reason, there is virtually no sector where colour measurement is not important for manufacturing companies. It should be particularly noted that colour is not merely a descriptive expression but is actually defined by numerical data and can affect the entire production process. For colour measurement to be performed correctly and in a compatible manner between companies, the technical properties of standards and devices should be considered, and the models of these devices should be determined in consultation with experts in colour technology. Konica Minolta's measurement devices contribute to quality control and precision improvement in various sectors. Our spectrophotometers, colourimeters, and other colour measurement devices play important roles in supporting various production sectors. Konica Minolta contributes to the development of quality and precision, which are indispensable to some sectors, with high-precision measurement devices, and provides proven colour measurement systems to the paints and coatings sector. Konica Minolta devices and software solutions, covering all applications from raw materials to finished products, are widely used in the sector for quality control and colour formulation in the laboratory or in production.