Mathematical model for prediction of colour in the aging of waterproofed porous face ceramic

Abstract

This article studies the effect produced by the natural aging process in the chromatic variation on the porous face ceramic treated with water repellents, theoretically colourless, and selected according to their chemical composition. The pottery is waterproofed with each product, leaving it to age in a natural environment for twelve months, and quantifying in each month the histogram values (RGB colour space) and analysing the chromatic variation produced. In the aging process there is a general trend for all products to the loss of red and the gaining of blue, modifying its hue to tonalities which are called "cold", there is a linear relationship in each of the months of the tested materials between the initial colour and the waterproofed ceramic with each of the applied products, being possible the prediction of the final colour to be acquired in each month, depending on the applied waterproofing product.