The Canon EF 50mm f/1.8 II is not a macro lens. In general, “true macro” means 1:1 magnification, and the 50mm f/1.8 does not offer that.

For photographing 2D artwork, true macro magnification usually isn’t the main reason to choose a macro lens. The bigger advantages are typically low distortion and a flatter field of focus, which help keep artwork sharp and accurately rendered across the frame.

Based on the answers, the EF-S 60mm f/2.8 Macro is a strong fit because it is a true 1:1 macro and also has the flat-field/low-distortion characteristics useful for copy work. The EF 50mm f/2.5 Compact Macro can also be a good choice for artwork reproduction even though it does not reach 1:1, because that missing magnification is not important for this use.

So: if your goal is reproducing flat artwork accurately, the 50mm f/1.8 is not the best choice. A macro-style lens such as the EF-S 60mm f/2.8 Macro or EF 50mm f/2.5 Compact Macro is better suited.