Once the surface has been properly cleaned and all accretions have been removed and/or washed away, leave the surface to dry thoroughly. The drying time will depend on a number of factors such as temperature, humidity, ventilation etc. Once it is dry, the walls and any plants should be covered with a sheet to prevent contact with the acid stain as a result of any spills or splashes.

Put on the necessary safety clothing and follow all the safety precautions
For a large area, the color solutions are more easily applied with a sprayer, but a brush or roller is also suitable. Spray application of the stain makes the job easier, but it is equivalent to any other method of application (remember that the sprayer must be made of plastic material).

If the area is small, a roller or a brush can be used. When the stain is applied by brush, use a circular motion to prevent visible traces of the brush on the concrete. When a roller and/or brush is used, pay attention not to splash, drip or leave pools of the StainColor, because these areas will dry darker.  Use only fresh stain on areas such as new surfaces.

Acid StainColor from Design Systems can give off smells and gas when they are being applied.  Four StainColors contain coloring agents besides acids and other inorganic minerals. These colors are Fern Green, Copper Patina.
These stains may not react like other StainColors, but they contain the same quantity of acid as any other of the StainColor range.
In the case of a double color process, let the first color dry and then apply a second layer in the same way. Leave to dry for approximately 4 hours. For a double layer of StainColor, make sure to test the compatibility of the colors. Similar procedures can be used for applications on concrete that is set vertically.
Once all the layers are dry, the surface can be rinsed with water. Use the utensils indicated above. The water that runs off may be slightly tinted and acid, and could stain other areas and damage plants. The water and the tools should be disposed according to municipal and state laws. Rinse until the run-off water is completely clear.

Mixing colors:
With the StainColor range, old and opaque concrete can be transformed into a fine paving with a marble effect. Sometimes, a number of different colors can be used on a paving. To do so, all you need to do is follow these instructions:

First of all, two of the StainColor tints can be mixed together in liquid form, and the result will be a mixture of the two. However, because of the nature of the acid stains, the colors might not react well together. You are recommended to perform tests to find the right mixture.

In the second place, the commonest way of mixing two or more colors is to unite them when they are already dry. This is done by applying one level of a color and then letting it dry, and a second color is then applied over the first. The first color is generally sprayed over the entire paving and the second color is usually applied only on patches. This procedure is normally carried out with sprays to apply the stain liberally. If it is carried out correctly and with a brilliant, shiny seal, the paving will almost look like marble.

Concrete paving can also be incised, printed and/or shaped with a flexible whip to obtain other desired effects before or after staining. Prints can be used on already stained paving. Then, when the paving is sanded and the print removed, the original color of the concrete will be visible. This may be colored with a different acid StainColor or left as it is to bring out the effect of the colored concrete.

SEALING:

To obtain a long-lasting finish and to enhance the color, it is important to seal the area that has been stained. The sealant in question can be satin matt or glossy, and is done with various types of products, such as DS-CS. These products are used according to the amount of wear and tear that the paving has to sustain and according to the type of finish that is desired. For methods of application and advice on use, consult the technical specifications.
  
ATTENTION:

The acid StainColors from Design Systems are corrosive fluids and must be treated with care. All safety precautions must be taken. The stains can cause serious irritations and burns to the eyes and skin. Contact with wounds may cause ulcers. Breathing in constantly or repeatedly may cause ulcers in the nasal membrane.

This is a product for professional use. Before application, consult the technical specifications.