Stamp size and image checks

1. Calculate print dimensions

Pixels = physical size in inches × PPI, rounded up. 1 inch = 25.4 mm. This is a target calculation, not a guarantee of printer quality or embedded DPI metadata. Confirm production requirements with your supplier.

Download A4 size test (PDF)

Print at 100% / Actual size, with “Fit to page” disabled. Measure the 100 mm control line with a ruler before comparing the 30, 35, 40, 45 and 50 mm circles. Printer margins and scaling can change the physical result.

2. Check a PNG file

Choose a file to measure transparent, partly transparent and opaque pixels. A white-looking pixel is not necessarily transparent.

3. Preview at a calibrated size

Measure this reference line on your screen with a ruler. Enter its measured length in mm. Calibration applies only to this screen and browser zoom; repeat it after either changes. Without calibration the display is only an approximation.

Reference line: nominally 100 mm

The preview uses your calculated width. Scroll if it exceeds the available space; it is not shrunk to fit.

4. Compare the same design in SVG and PNG

Both views are generated now with Stampzio’s renderer from the same editable example. Change the wording or letter size to test crowding. PNG has a fixed pixel grid; SVG keeps text and lines scalable, but fonts and embedded bitmap images can still affect the result.

What these checks cannot establish

Transparency checks count alpha values; they do not remove a background or assess image rights. A screen preview cannot test ink, paper, manufacturing limits or optical readability for every reader. Print a proof and inspect the smallest letters before production.