What image resolution is required?
The resolution should be 1.5x to 2x the final line count at final size. For example: A 50 lpi print would need a resolution of 75 to 100 dpi at final size. If the art were 1/4 size of the final that means you would multiply the final required resolution by the enlargement of 400%. 75 x 400%= 300 dpi at 1/4 size would be fine for 50 lpi final.