Semi-Log · 3 Decade

About Semi-Log · 3 Decade

Semi-log paper extended to three decades on the vertical axis (1, 10, 100, 1000) - wide enough to plot signal-attenuation, dose-response curves and population-growth data that spans three orders of magnitude on a single sheet. Further reading: A practitioner reading list covers the standards lineage in more depth.

Standards lineage

Formal definition in ISO 31-11:1992 mathematical signs.

A short history

Three-decade semi-log paper was patented by the Keuffel & Esser company in 1903 and remained their best-selling specialist drafting paper for more than 70 years.

Where designers reach for it

• Signal-attenuation Bode plots
• Dose-response pharmacology curves
• Bacterial growth-curve plots
• Earthquake-magnitude (Richter scale) plots

Printing this grid

Every variant on this page is delivered as a vector SVG with physical millimetre dimensions baked into the file, so a compliant printer driver will reproduce it at exact 1:1 scale by default. Choose the sheet size that matches your printer tray, set scaling to 100 % (never "fit to page"), and verify with the calibration check on our how-to-print guide. Buyer's guide: Comparing the major architectural scale rulers can help you pick the right physical scale rule to use over the printed grid.