Print an image at an exact size
A photo that looks right on screen can still print too small. The file needs a physical size, and the print dialog needs to preserve it.
Start with the size on paper
Decide the width and height you actually need: for example, a 6 × 4 cm image for a craft project. Those measurements describe the printed frame. They are different from the image’s pixel dimensions and from how large a preview looks on your monitor.
In the print layout tool, open your image, enter 6 for width and 4 for height, and leave the unit set to centimeters. Choose the paper that will be in your printer. A4 and US Letter are different sizes; changing between them in the print dialog can trigger scaling.
Choose what happens at the edges
Fit whole image keeps everything and can leave white space inside the frame. Fill frame uses a centered crop to fill it completely. Neither setting stretches the picture. If the shape of the source image matches the shape of the frame, both give the same geometry.
A 1,200 × 800 pixel image is 3:2. A 6 × 4 cm frame is also 3:2, so no crop is needed. At that print size the image has 508 pixels per inch. You can reproduce the calculation in the print-size checker.
Save the sheet, then preserve its scale
- Select Print / save PDF. A separate print window opens with the sheet.
- Choose the same paper size shown in the tool. For a file, select your browser’s Save as PDF destination.
- Use 100% or Actual size. Avoid Fit, Shrink or Scale to fit when the physical measurements matter.
- Turn off headers and footers. The generated document already defines its own page size and margins.
- If you later print the saved PDF, check these settings again in the PDF viewer.
Check one copy before a full run
Print one sheet and measure the frame with a ruler. Printer drivers and viewers can override the file’s dimensions. If a 6 cm frame measures 5.7 cm, something has scaled the output to about 95%. Changing the image’s DPI label will not correct that print-dialog setting.
Use margins your printer can reproduce. The tool can place content close to an edge, but it cannot make a printer print beyond its printable area. Small cut marks can also be clipped when margins are too tight.
What the tool can verify
The layout uses millimeters to position each frame in the printable document. Its calculations are covered by automated tests. A PDF preview is still not a measurement of your printer’s physical output; a short ruler check remains the final step for your setup.
References
W3C: CSS units and physical lengths
Adobe: printing large documents and adjusting scale