Printing help
A correctly dimensioned file can still come out at the wrong size when a printer applies fitting. Start with a single sample sheet, especially for rulers, shapes or grids that will be measured.
Match the file, paper and scale
Select the paper size and orientation in the generator before downloading. Load the same size in the printer and check that the print dialog uses it. Choose Actual size or 100% when physical dimensions matter. Fit, Shrink and Scale to printable area may change the result.
Turn off browser headers and footers when printing a sheet from a browser. If the Print button does not open a dialog, download the PDF and print from your PDF viewer instead. The screen preview is reduced to fit your window; do not hold an object against it as a measurement reference.
Check a known distance
Use the print calibration tool and compare its reference marks with a trusted physical ruler. Check both horizontal and vertical distances. Only start a measured project when the sample agrees closely enough for your task.
A paper ruler is not a calibrated precision instrument. Do not use a homemade scale for medical, safety critical or precision manufacturing decisions. Printer drivers, paper handling and cutting can introduce errors outside the generator.
PDF, SVG or PNG?
Use PDF for routine printing and SVG for compatible vector editing. A PNG is convenient for an image document or presentation, but the receiving program may resize it. Its resolution metadata does not guarantee that another application will preserve the intended physical size.
Choose a larger PNG resolution only when you need it. A3 or larger sheets at high resolution require more browser memory. When an image request is too large, choose a lower resolution or use PDF or SVG.
Clipped edges or faint lines
Most printers have a nonprinting border. Increase the generator's margins if marks fall outside that area, rather than shrinking a ruler to fit. A continuous twelve inch ruler is longer than an A4 or Letter page and needs a suitable larger sheet.
If light guide lines are hard to see, increase the available line weight or use a darker stroke. Check the preview and print one sample. Fine lines on a screen may look different on an inkjet, laser printer or photocopy.
A small first print saves a lot of paper
For a classroom, check the writing space, labels and contrast with the actual pens or pencils learners will use. For music, count the staff or string lines. For a craft pattern, test the cell proportions against your own swatch. Then print the number of copies you need.