Sometimes you can, sometimes not. Some paintings stretch at least twice without problems. Some of them cannot be increased even by 10%. This largely depends on the texture of the watercolor paper and how this texture will manifest itself when enlarged.

In addition, size is also part of the painting and changing it can distort the impression.

For those pictures Α4, which were able to be enlarged earlier with an acceptable result, the description contains a note about such a possibility. If there is no note, then this does not mean the impossibility of increasing. Maybe we haven't tried to enlarge this original yet. Write to us and we will try to solve the problem.