In the field of painter's crafts white colour has long dominated. In recent years this has changed. Today a wide range of color shades is used, including several thousands of shades. What started cautiously, with the gradual promotion of pastel colors has recently continued with intense colors, such as a strong, pure red, yellow and orange. Professional application of the color shades, however, requires special knowledge. Problems are caused by lack of knowledge about the physical specificities of these shades, above all their hiding power and the so called "writing effect" on the coloured surfaces. Intensive colour shades are increasingly getting importance, for high quality application and nice final appearance on the painted surfaces not only a sense for design is necessary but also technical knowledge on characteristics of suitable coating materials.
Hiding power is the coating's ability to cover paint or colour differences on the surface. It can be achieved with pigments and can be improved with suitable fillers. In principle fillers have a worse hiding power than pigments, but they contribute to the coatin's thickness. Fillers have their own »colour« and can have influence on final coating's colour shade, therefore with intensive colour shades we use them in limited quantities. The hiding power depends thus on type and quantity of the used pigments, colours shade and the coating's thickness. Thereby white and pastel colour shades have. a stronger hiding power as a rule. For the preparation of colour sghdes we make basis, which are white, semi-white or transparent. Pastel colour shades are made on white basis. This contains besides high covering white pigment (titanium dioxide) a large portion of different fillers, which improve hiding power and whiteness of a dry coating. They also have influence on increase of coat thickness, which additionally improves the hiding power.
For other colour shades there are a number of pigments, which are according to chemical composition divided into inorganic and organic pigments and have much influence on the coating's hiding power. Inorganic pigments are according to the chemical composition divided into iron oxides (yellow oxide, red oxide, black oxide), chromoxide (green), ultramarine (blue, purple), complex inorganic pigments (cobolt blue, cobolt green), bizmutvanadat (yellow) and so on. They are distinguished for good hiding power and good light resistance, they are not glossy and do not give vivid intensive colour shades. These colour shades are known as »earth colours". Organic pigments are produced synthetically. Depending on the chemical composition they are very complex (for example, phthalocyanine, azopigments and black soot). They have a number of fine particles and are more glossy than inorganic - provide intensive live colour shades,have a worse hiding power and are less light resistant than inorganic pigments. Today's "colored world" requires a lively intense colours (vivid red,sunny yellow, orange, pure strong orange), this can be achieved only with very glossy, therefore organic pigments. Moreover, at the protection of facade surfaces light resistance is important, which we can achieve with the selction of type and quantity of binder (among them ipure acrylate and styrene-acrylate). The type and amount of binder system is limited with maximum pigment addition and maximum hiding power, which can be achieved.
As due to physical properties with intensive, glossy coatings it is necessary to expect a worse hiding power, the differences in a substrate are often seen in several layers. Coating covers only with a greater thickness, more layers mean higher costs. Latex coatings, which are rich in binders and have quite a high gloss allow only minor changes in the quantity of pigments or fillers, as they would otherwise have influence on gloss level. In glossy paints from latex there are often small quantities of fillers, therefore intensive shades have worse hiding power than the same shades in a matted version. Due to the large proportion of binder these paints have good sagging, coats are thinner, which again causes worse hiding power. Already in the past the painters solved this problem with pastel, good hiding preceding coat in a colour shade, the same as the desired colour shade. In this case twice coat in a desired colour shade is sufficient. This procedure is even more recommendable, as today we prepare shades in mixing units using different bases. The basis for pastel colours is white, for intensive transparent. The user may use for achievement of the desired hiding power as pre-coat with intensive colour shades a pastel colour shade with good hiding power or the selected intensive colour coat with addition of white basis (5-10 percentage). Some coatings have besides white, semi-white and transparent still a red and yellow base (e.g. ., SPEKTRA latex mat). On the colored bases formulations are made for intensive, vivid colour shades (red, orange, yellow, yellow-green, brick red, etc.). As the colored base is in itself with high hiding power, also the final colour shade is not problematic, so that for a nice and good hiding final coating two coats of the selected colour shade are sufficient in major cases.
In addition to problems with hiding power, especially with intensive coloured matted surfaces in interior rooms, another problem occurs – if we drive on the wall surface with a sharp object, a light scratch occurs. Each top paint contains besides the pigments the fillers, they are with coloured coatings covered by pigments. At gloss coatings pigments are coated with a binder, at matted coatings they are often on the surface. At scratches on matted surfaces pigments are driven to side and white fillers come up. In order to avoid »writing effect«, with intensive colour shades the decision for glossy coatings is recommendable. With silky gloss coatings (SPEKTRA latex semi-matt) this problem in interior rooms does not occur any more. The matted coating we can protect e.g. with SPEKTRA DOMFLOK lacquer (transparent coating with a high binder portion), which covers the pigment and protects the coating against the scratches. The users, who anyway decide for matted coatings should be warned about »the writing effect«. With very intensive matted coloured shades there is a »writing effect« clearly evident on the surface.
Useful advice
In order to get suitable results for the application of intensive colour shades, you should consider the following: Under intensive shades you should apply the preceding pastel colour shade in the colour shade, similar to the desired shade or the shade, made on the coloured substrate. The matted interior coatings in intensive colour shades incline to »writing effect«, pigments are lying free on the surface and are driven at scratches aside. At intensive colour shades we have to use at least silky-gloss coats or protective transparent coating, which contains much binder. Thereby we can use different application techniques, e.g. jeans technique, application with a gloove, brush, tampoon and others. back to top
