The original works of artists are all certified, and some limited edition paintings signed by artists themselves are also certified, such as Japanese master Yayoi Kusama. It is meaningful to stamp the certificate with my signature. Some online stores say that the limited collection certificate is actually the certificate printed digitally by the merchants themselves. The content of each certificate is exactly the same, and there is no author's signature at all. In fact, it is a deception to consumers, just like printing a certificate for yourself. Everyone should pay attention to screening.