For the facades it is crucial to emphasize the importance of color choise. For long persistence of color we recommend to choose inorganic pigments based shades.
The pigment is the key component to determine the aesthetic of an object.
Besides the coloration of the object it provides the light and weather fastness of facade as well. Therefore the beauty of an object is kept for a longer period of time.
Light fastness: the Sun radiates the light of different wavelenghts; UV light degrades the chemical bonds in pigments, the consequence of this process is color bleeding.
Weather fastness: acid rain, SO2 and limescale cause stains or color change.
Light and weather fastness data apply to the pigment and not to the paint or colorant as semi product. Such data is provided by pigment manufacturers as a base to choose the most suitable pigment.
In HG MIX colorants the optimal light and weather fast pigments are being used.
Usually light and weather fastness tests last couple of years. The data are available for masstone and for reduction with white (usually in ratio 1:25). For the faster results we are using accelerated aging in light and weather cambers. The correlation between these two methods is very good.
Inorganic colorants (DH 1, 2, 3, 14, 20, 22, 23, 24 in 25) have high light and weather fastness also in pure, bright tones as well as in undertones.
Organic colorants (DH 4, 6, 9, 13, 15, 16 in 17) are chemical more sensible to light and weather influences over the years.
The consequences of the influences meantioned show as a bleeding of color of facade, pigment flooting and floating, mottled appearance on the surface of facade.
Organic pigments are manufactured with chemical synthesis of organic compounds, while the inoganic pigments are basically grinded minerals with chemical treated surface.
Inorganic pigment parts are bigger, with stable chemical bonds and are harded to be washed away.
Alkaline substrate can damage chemical bonds in organic pigments, they become loose and in the presence of UV light and moisture they can break and the pigment is ruined.
If we are talking about fastness of facade we must consider that the most important is the pigment. Amount of binder in wall paint and in plasters is significantly lower than in other pigmented coatings therefore the pigment is more exposed to outdoor influences which accelerates the process of degradation.
In facade paints is highly recommended to use inorganic colorants, but it is not possible to gain intensive, bright shades. We should avoid using those shades from the light and weather fastness point of view.
Colour stability depends of chemistry, crystalline modification of pigment, its size and concentration. Important role plays also porosity of system to which pigment pastes are added (silicone system for example is very porous, that is why the organic pigments are not being used). Also the surface to which the coating is being applied is of great importance (if the surface is basic like in silicate systems the use of organic pigments could lead to pigment disappearing).
On bleeding of color of facade also influences the binder itself, power of UV light, moisture amount, alkalinity, dryness of the surface, paint density and the application itself.
Due to different customer needs we offer a wide variety of facade shades, also darker ones, like orange or dark red.
But we also must warn our customers that this kind of shades will loose their intensity over the years and will start to fade.
In order to make the choise easier for our customers, a fandeck SPEKTRA Terra was made. To the color shade T 400 there are only shades made with inorganic colorants.Customers can now easier decide which color shade suits their needs best.