CMYK vs RGB: why colours shift between screen and paper

An image can look perfectly sharp on your phone and turn into a pixelated mess when printed. The reason is DPI, and understanding it solves most print quality issues.

What DPI means

DPI stands for Dots Per Inch. It is the number of individual dots a printer places in a one-inch line. More dots per inch means finer detail and a sharper image.

A 300 DPI image has 300 dots in every inch. A 72 DPI image has 72 dots in every inch. The same physical size, the same photo, but the 300 DPI version has more than four times the detail.

Why screens hide the problem

A phone screen displays at around 400-500 pixels per inch. A laptop screen at 100-200. Neither shows you the difference between a 72 DPI image and a 300 DPI image — they look identical on screen.

The printer, however, will print at the image's actual DPI. A 72 DPI image on a 4 x 6 inch print will have visible pixels. A 300 DPI image on the same print will be sharp.

The DPI rule of thumb

• 300 DPI — standard for photo prints, marketing materials, anything viewed up close
• 150 DPI — acceptable for large prints viewed from a distance (posters, banners)
• 72 DPI — screen only. Never use 72 DPI images in print.

How to check an image's DPI

On most computers:

• Right-click the image file, choose Properties or Get Info
• Look for "Resolution" or "DPI"
• 300 means good for print; below 150 means trouble

In Print Studio, the export panel shows the effective DPI of each image in your project at its current size. Anything below 150 DPI is flagged.

How to fix a low-DPI image

The honest answer is: you cannot reliably fix it. Resampling a 72 DPI image to 300 DPI does not create new detail — it just makes the existing pixels bigger.

Your options are:

• Use a higher-resolution source image if available
• Reduce the print size so the lower DPI is acceptable
• Accept the lower quality for that image

When DPI does not apply

Vector graphics (shapes, text, logos) are not DPI-dependent. They are defined by mathematical curves and print sharp at any size. This is why logos should be vector when possible.

FAQ

What is the difference between DPI and PPI?

DPI refers to printed output. PPI (Pixels Per Inch) refers to screens. They are related but not identical. The key concept is the same: higher number, more detail.

Can I make a low-DPI image higher DPI?

You can resample, but the result is no sharper than the original. There is no software that adds detail that was not captured.

What DPI do I need for a business card?

300 DPI is standard. Anything below 250 will look soft.