What this canvas can actually ink
300 DPI is a relationship, not a button
A square export is roughly 2160×2160 after 2× capture. 2160 ÷ 300 ≈ 7.2 inches. That comfortably covers a 5×7 with crop, a 6×6, and many small frames. An 8×10 for a true 300 DPI file wants 2400×3000 — already past this square. A3 for a 300-pixel-per-inch lab wants about 3508×4961. We do not have those pixel boxes. If a lab will accept 150 DPI, you can push physically larger with softer results; that is a lab conversation, not a hidden “poster mode.” 16:9 capture (~3840×2160) is a wide 12.8×7.2 inches at that same density — a small panorama print, still not a trade-show banner.
Paper sizes we do not simulate
There is no A4 (210×297 mm) or US Letter canvas in the dropdown. You can place a 4:5 or 1:1 board onto A4 in a print dialog and live with margins, or you can design the collage as a centered image on a larger InDesign/Word page. Canvas-wrap shops need extra bleed for the fold; we do not generate mirror edges. Photo-book services each have their own box — treat this PNG as a photo among photos, not as a imposed spread.
Color and codec for labs
Screens are backlit RGB. Cheap labs punch saturation. PNG avoids an extra JPG generation if the board has graphic edges; many consumer labs prefer JPG anyway. Soft-proofing and ICC profiles are out of scope. If color is contractual (a fashion lookbook), this studio is a layout comp. For gifts and family frames at ~7 inches, export PNG or high JPG from original camera files, not from a screenshot, and you will be fine.