Novel blue pigments were prepared from copper, magnesium, aluminum nitrate solutions and phosphoric acid with pH adjustments (pH 5, 7, 9). The obtained precipitates were heated at 300, 500, and 700 °C for 1 h. The precipitates and their thermal products were estimated with X-ray diffraction (XRD), infrared (IR) spectra, ultraviolet–visible (UV–Vis) reflectance spectra, and L*a*b* color […]