When a customer downloads your digital print and takes it to their local print shop, they're trusting that the file will look as good on paper as it did on their screen. That trust lives or dies with one number: DPI.
What DPI Actually Means
DPI stands for "dots per inch" — how many dots of ink a printer places in each inch of the output. 300 DPI is the standard for professional-quality print. At 300 DPI, the individual dots are small enough that they blend together and look crisp to the human eye at normal viewing distance.
At 72 DPI (screen resolution) or even 150 DPI, those dots are visible as a subtle blur or pixelation, especially on larger prints.
The Trap Most Sellers Fall Into
Here's the thing: just because your file is large doesn't mean it's 300 DPI. A 3000×4200 pixel image at 72 DPI will print at roughly 41×58 inches at screen quality — blurry and unusable. The same image tagged as 300 DPI prints at 10×14 inches, sharp and professional.
The pixel dimensions are identical. The metadata is different. Your printer reads the metadata.
How PrintPrep Handles This
Every output from PrintPrep has 300 DPI metadata embedded using Sharp's `withMetadata({ density: 300 })`. The pixel dimensions are calculated to match — a 5×7 inch output is exactly 1500×2100 pixels. No guessing, no manual settings.
What to Tell Your Buyers
Include a note in your listing that your files are "300 DPI print-ready." Most buyers won't know what that means, but print shops do — and it signals that you know what you're doing.