Image fundamentals

Pixels per inch (PPI)

Also known as PPI, image PPI

The number of image pixels assigned to one inch at a chosen physical output size.

By EngravePrep Editorial Team

In the workflow

Why Pixels per inch (PPI) matters

PPI describes the image grid, while a laser's DPI or line interval describes scan spacing. Software may blur those labels, so confirm both the pixel dimensions and physical dimensions.

Practical check

How to evaluate it

Calculate PPI from the image's pixel dimensions and intended physical dimensions. Then compare that density with the selected scan spacing instead of assuming the two values are automatically identical.

Go deeper

Learn the DPI and line interval relationship, calculate output pixels, avoid overlapping scan lines, and preserve exact size in a photo workflow.

Read the complete guide

Prepare the pixels

Use the terminology in a real photo workflow.

Crop, tune, size, dither, and export a one-bit PNG on iPhone or iPad. Test the result on scrap with your machine and material guidance.

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