Digital versus print image quality. The rules that actually matter.

DPI is dots per inch. It is a measure of how densely pixels sit on a printed page. 300 dpi at print size is the minimum for reliable packaging. Below that, the eye reads softness and the print reads cheap.

Resolution is the pixel dimensions of the file. A 1920 by 1080 image at 300 dpi prints cleanly to 6.4 inches by 3.6 inches. If you need the same image at pack front size, you need a bigger file. Enlarging a small file to fit a large surface is why so many packs look soft. The pixels do not multiply. They just stretch.

Colour space is the language the file speaks. Digital images live in sRGB. Print lives in CMYK. Different colour ranges, different behaviours. A vibrant sRGB image sent straight to a CMYK press comes back muted. Conversion has to happen with intent, ideally with an embedded ICC profile that matches the printer's press.

• 300 dpi at final print size. Minimum. Some fine detail work benefits from 600.
• CMYK colour space with an embedded ICC profile. Fogra 39 for European offset. GRACoL for North American. Confirm the profile with the printer.
• Vector where possible. Logos, icons, illustrations. Vectors scale without loss. Rasters do not.
• Layered files preserved. PSD, AI, or PDF with layers. The printer often needs to make small trap or bleed adjustments.
• Bleed of 3 millimetres on every edge. The design continues into the bleed area so trimming does not expose the paper.
• Fonts outlined or supplied. Missing fonts break files at the press.

• 72 to 144 dpi at display size. Higher for Retina and 4K displays.
• sRGB colour space. Standard for screens and web.
• Compressed formats. JPEG for photography, WebP or AVIF for modern web efficiency, PNG for graphics with transparency, SVG for anything vector.
• File size discipline. A large hero image should compress to under 200 kilobytes without visible quality loss. A pack render should not be 5 megabytes.

• Upscaling. Taking a 500-pixel image and blowing it up to fill a pack front. The pixels do not exist. Nothing you do in Photoshop invents them.
• Wrong colour space. Designing in RGB and converting to CMYK late. The client signs off on saturated screen colours that the press cannot reproduce. Disappointment is guaranteed.
• JPEG for logos. JPEG compression softens edges. Fine for a photograph, ruinous for a brand mark that has to be crisp.
• No bleed. Design goes right to the edge, printer trims a millimetre off centre, and now there is a white line on the pack.
• PNG for print. PNG lives in RGB. It has no place in a pack file that has to go to press.

• Colour space verified against printer specification.
• All raster images at 300 dpi at final print size or higher.
• Bleed of 3 millimetres present on every trimmed edge.
• Fonts embedded or outlined.
• Spot colours defined and named. Foils, varnishes, embosses called out on their own layers.
• Dielines locked. Registered against the printer's die file.
• Overprint and trap settings checked for text on colour and colour on colour.
• Regulatory copy checked. Ingredient panel, allergen callouts, barcode format, country of origin.
• Final PDF exported to press-ready specification with hi-res preview embedded.

Every hour spent on the prepress checklist saves two days at the printer. The checklist is not overhead. It is the difference between a pack that ships and a pack that stops.

If you are sending an asset to a designer for packaging, send the largest, highest-quality version you own. If it is a logo, send the vector. If it is a photograph, send the original camera file. If it is a product render, request it at print size in CMYK from the studio that built it. The designer will scale down and convert. The designer cannot invent quality that was not there.

The reverse rule holds for anything going to screen. Send a compressed, sRGB, screen-sized file. A 50-megabyte TIFF on a website slows everything. Right file, right medium, every time.