Buy for the exact sheet dimensions and verify each required function at that size.
Name the exact size you need
A3, tabloid and larger photo sizes are not interchangeable. Begin with the dimensions required by the project, then verify that size in the printer’s supported media list. Do not rely on a wide-format label without checking the actual maximum sheet size.
Check printing and scanning separately
A device may print a larger sheet than its flatbed or document feeder can scan. Duplex and borderless limits can differ as well. Record the maximum size for each function you need instead of assuming one number applies to the whole machine.
Plan for the open trays and the file
Measure the printer with the necessary trays extended and leave space to collect output. In the application, match document and paper sizes before checking the preview. Print a proof at the intended scale when dimensions are important.
Sources & further reading
HP wide-stock paper setup exampleReady to put it into practice?
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