Then the painting styles of different times are different. A painting is out of date. It's a fake, so is calligraphy.
3. Finally, it is identified from the painter's habit, name and signature. The identification of seals can also be started from two aspects. First, the forms and engraving methods of seals are different in different times. The second is to look at the inkpad. After Yuan Dynasty, it was mostly oil modulation, and before Song Dynasty, it was mostly watermark.