Painting on copper plates goes back to perhaps the 1200s.
Until about the year 1700 copper sheets were produced by happering a copper ingot.
Leonardo did conceive of a rolling system to produce metal sheets but it was not until the early 1600s that such machines were built.
Today, when trying to decide if a painting on copper dates from 1550 or 1750 (or later) one approach is to determine if the sheet was rolled or hammered.
If you are trying to date a painting on a copper and need some assistance, contact us, we will probably be able to help you.