How to Choose Color of Pre-painted Steel?
Choosing the color of pre-painted steel sheet mainly depends on the matching with the surroundings, use purposes, and your own preferences. But considering the heat reflection ability, weather resistance, and other factors, the light-colored pre-painted steel is more recommended.
Reflectivity of Different Colors
The reflectivity of different colors is different. Generally, the higher the reflectivity of light, the less heat is absorbed, so the lower the temperature. The experimental data shows that the temperature of the white color coated steel surface is 10 degrees lower than that of the blue ones and 19 degrees lower than that of the black ones. So if the local climate is hot, light-color steel sheets are better for roofing or wall panels.
Color Corrugated Sheets
Below is a table showing the reflectivity of different colors.
| Colors | Reflectivity | Reflection effect |
| White | 84% | Great |
| Milky white | 70.4% | Good |
| Light red | 69.4% | Good |
| Beige | 64.3% | Good |
| Light green | 54.1% | Good |
| Light blue | 45.5% | Medium |
| Brown | 23.6% | Poor |
| Black | 2.9% | Very poor |
For color-coated steel sheets, the thermal expansion rate of the coating and the steel sheet is different. In particular, the linear expansion coefficients of the metal substrate and the organic coating are quite different. When the temperature changes, expansion or contraction stress will occur at the interface between the substrate and the coating. If they are not properly released, the coating will crack.
Color Retention
The exposure tests (8 years of exposure to the sun in Hainan Province) of the same paint and different colors show that the light color paint has less discoloration. The following table shows the exposure test results of different colors.
| Colors | Original gloss | Current gloss | Color difference | Original thickness | Current thickness | Degree of chalking |
| White | 35% | 3% | 1.49 | 24μm | 20μm | Level 2 |
| Red | 45% | 3% | 2.48 | 24μm | 20μm | Level 2 |
| Light yellow | 26% | 2% | 1.26 | 24μm | 17μm | Level 2 |
| Green | 41% | 2% | 3.43 | 24μm | 17μm | Level 2 |
| Blue | 41% | 2% | 4.95 | 24μm | 17μm | Level 2 |
There will be color differences if you use prepainted steel sheets from different manufacturers or batches in the same construction projects. The color may look the same or similar during construction, but there will be serious color differences after several years. Therefore, it is strongly recommended to order the same batch for the same project at one time. Different batches even from the same supplier may use different paints, which will increase the possibility of color difference.
Coating Gloss
The choice of coating gloss is mainly according to the use purposes. For example, medium and low gloss color coated steel is mainly for construction uses; while high gloss color-coated steel is mainly for home appliance uses.
