What about sizing?
Framing sizes can vary between the European Union (EU), the United Kingdom (UK), and the United States (US), and they are often expressed in different measurement systems. Here's an explanation of the different framing sizes in each location:
European Union (EU) Framing Sizes:
A4: 21 x 29.7 cm (8.3 x 11.7 inches)
A3: 29.7 x 42 cm (11.7 x 16.5 inches)
A2: 42 x 59.4 cm (16.5 x 23.4 inches)
A1: 59.4 x 84.1 cm (23.4 x 33.1 inches)
A0: 84.1 x 118.9 cm (33.1 x 46.8 inches)
United Kingdom (UK) Framing Sizes:
A4: 21 x 29.7 cm (8.3 x 11.7 inches)
A3: 29.7 x 42 cm (11.7 x 16.5 inches)
10" x 8": 25.4 x 20.3 cm (10 x 8 inches)
16" x 12": 40.6 x 30.5 cm (16 x 12 inches)
United States (US) Framing Sizes:
8" x 10": 20.3 x 25.4 cm (8 x 10 inches)
11" x 14": 27.9 x 35.6 cm (11 x 14 inches)
16" x 20": 40.6 x 50.8 cm (16 x 20 inches)
18" x 24": 45.7 x 61 cm (18 x 24 inches)