Ceramic and porcelain doorknobs can add an old-world charm to any home. However, it is not uncommon for these to lose their sheen. The good news is that the same can be easily painted using a fresh coat of paint or using spray paint to attain the best results for your needs. Since porcelain is a slick material, the right preparation can lead to a smooth and long-lasting finish.
To paint the same, remove the knob using a screwdriver. Then mix one-part ammonia in one-part water and sand the same. Once done, use the same to apply on the doorknobs. Also, you can spray paint the same.