How to easily establish when a smoothing compound is dry?

With UZIN NC 111 BiColor.

The product data sheets for any smoothing compound state when they should be ready to receive the floor covering. However the time specified is normally establish in a controlled laboratory environment and the actual time in practice can vary depending on the project location or climate conditions. Thanks to UZIN NC 111 BiColor a unique colour changing smoothing compound, it is easy to determine when to install the floor covering with the naked eye. This is because the colour changes from green (when wet) to salmon (when dry). This saves moisture checks and problems related to premature installation, such as unpleasant bubbles or odours. UZIN NC 111 BiColor is the first intelligent smoothing compound!