PPI and DPI are related, not interchangeable
Learn why image pixels use PPI, printer dots use DPI, and PaperSize calculates a raster canvas from physical inches and PPI.
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Understand every dimension in the result
Three practical articles separate PPI from printer DPI, explain the ISO A series, and turn a physical format into an image canvas without hidden assumptions.
How the ISO A-series paper sizes fit together
See the exact millimetre bases for A3, A4, and A5, why the family keeps a common proportion, and why Letter and Legal are separate.
Read articleA4 and US Letter are close, but not interchangeable
Compare the exact dimensions and proportions of A4 and US Letter before choosing a sheet, layout, or pixel canvas.
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