Flex banner resolution and colour
A student volunteer is preparing a flex banner for a blood donation camp at a Bhubaneswar college. The finished banner is 8 ft x 4 ft (2438 x 1219 mm). The printer's template says 72 dpi at final size, CMYK. The volunteer builds the file at quarter scale (2 ft x 1 ft) at 300 dpi in RGB, places a 600 x 400 px logo at 2 in wide on the quarter-scale artboard, sets the headline in a rasterised image, and adds a photograph. The printer scales the file 4x to final size. On the proof, the headline edges look soft and the red blood-drop icon looks orange. The camp is in three days and the print shop can handle vector PDFs or high-resolution TIFFs.
1. Calculate the effective resolution of the logo at final size and explain the consequence.
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The quarter-scale artboard is 2 ft x 1 ft = 24 x 12 in. At 300 ppi the file is 7200 x 3600 px. A 600 px wide logo placed 2 in wide on that artboard becomes 8 in wide at final size (2 in x 4). Effective resolution is 600 px divided by 8 in = 75 ppi. That is below the 150 ppi usually wanted for a banner viewed at 1-2 m and far below 300 ppi; fine details and small text will look soft.
2. Explain why the headline is soft and the red icon looks orange, and state the production fix.
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The headline is soft because it was rasterised in the quarter-scale file and then enlarged 4x; any 300 ppi raster type becomes 75 ppi effective at final size, and interpolation blurs edges. Keep all type as live vector text in the PDF, or set it at final size. The red icon looks orange because the file is RGB and the printer converts to CMYK; a saturated RGB red is outside the CMYK gamut and shifts toward orange. Build the red in CMYK with a swatch, or use a spot red, and ask for a contract proof. Set small black type as 100% K only.
3. Specify the final file setup and a three-day workflow.
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Export a press-ready PDF: final trim size 2438 x 1219 mm, CMYK, fonts embedded or outlined only after saving an editable copy, images at 150 ppi at final size, vector logo. Check that the placed photograph is not enlarged beyond its native resolution. Ask the printer for a PDF proof at 1:10. With three days, skip a physical proof only if the printer accepts a soft proof plus a printed swatch for the red.