It is uncommon for photographs to be printed on A4 size paper. A4 paper is, 297 mm X 210 mm. Certificates are often printed on A4 paper.
Camframe stocks a range of colourful and plain mouldings ideally suited to A4 size frames. A3 is twice the size of A4 when the long sides are placed next to one another. Order your A4 frame from Picture framers Cambridge.