How much resolution for a poster print?

For a poster print, a resolution of at least 300 DPI (dots per inch) is recommended for high-quality results. This means that for an 18x24 inch poster, the image should ideally be 5400x7200 pixels. For larger posters viewed from a distance, such as 24x36 inches, a resolution of 150 DPI (3600x5400 pixels) may be sufficient. Always consider the viewing distance when determining the necessary resolution.