When using "Duplicate", changes made to a "duplicate" cause changes in primary product.

Hi there.

I have (example) 30 hoodies, each with different prints. All the informations are identical when comes to size, fabric etc… except for the artwork title.

I use “Duplicate” to spare time on setting up a new product from scratch, however when I upload new artwork to the Duplicated product, it replaces the

artwork in the initial product I used to make the duplicate from.

What am I missing here? What can I do to make sure the DUPLICATE it’s an individual product on its own and?

Regards

Seba