Regular appearance, straight edge, no distortion or warping, no defects and cracks on the front and back, and tile claws in good condition (to ensure firm hanging). When large tile factories manufacture colored tiles, the molds used are all high-strength aluminum alloys, which are smooth and regular, and the tiles produced are naturally smooth and accurate in size; Small factories use iron sheets as molds, which are inherently warped, and the tiles that come down cannot be leveled and standardized. This directly affects the paving effect. After paving, the roof cracks are large and irregular, and the waterproof, windproof and heat insulation effects are obviously poor. Judgment method: put the tile on the plane and click it to know whether it is warped and flat; You can tell whether it is straight by looking at the sides with your eyes.
Second, the colored layer
1) material. First, judge whether the colored layer is cement or paint. A good colored tile is composed of high-strength cement, inorganic pigment, resin and silica aggregate, with a thickness of about 0.5 mm, strong adhesion (made with ceramic tiles at the same time) and good weather resistance, and will not fall off or fade after decades of sun and rain. Most of this floor of the painted tile factory is painted with paint. The new tiles look bright when they are not laid, but they will change color and peel soon after they are laid. Observe first when distinguishing: the former has a certain thickness from the side and end, while the latter is very thin, and you can see the spray point of paint or the flow mark of paint at the end of ceramic tile. Then scrape it with a pointed iron: the former is hard and difficult to scratch, and the latter is exposed as soon as it is scraped.
2) color consistency. The coloring layer on the whole surface of a good tile is uniform, and there is no flow mark and color difference. The second tile is not, but the bright one is usually paint. Put multiple tiles together, and the colors of good tiles should not be different from each other.