Large art pieces I make are over 20 inches or 50 cm longest dimension.
They are best for larger spaces that allows to step back and view the piece from some distance. However, this does not imply the lack or detail or texture.
Examples of standard large artwork sizes:
- Imperial - 30 x 22 inches,
- B2 Standard ~ 28 x 20 inches (27.8 x 19.7"),
- Academic 24 x 18 inches,
- A2 standard ~ 23 x 17 inches (594 x 240 mm).
- Half-Imperial - 22 x 15 inches.