Semi-Log · 3 Decade on Letter · Landscape

About this template

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. See also: A short reading list on technical drawing standards can help you put any of these grids in their historical and standards-based context.

Best used for

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

Why Letter in landscape

North American 8.5×11" format (ANSI/ASME Y14.1 size A). Fits every desktop printer in the United States and Canada without a custom tray. The landscape orientation gives you 279 mm of horizontal run and 216 mm of vertical, which suits wide subjects - site plans, sequence diagrams, multi-column layouts - where the eye reads left-to-right. Trim and bleed allowances on consumer printers will normally remove a 5 mm strip from each edge; this grid is generated to remain measurable even after that trim, with no critical content placed inside the printer-margin band.

Standards and lineage

Formal definition in ISO 31-11:1992 mathematical signs. The Letter sheet itself follows ANSI A, and the title-block conventions assumed by this template come from ISO 5457:1999 - the international standard governing how technical drawings are framed, dated, and signed. Background reading: See our scale-and-projection guides for a deeper dive on how all the standards in this lineage interact in practice.

A short history of this grid

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.

Printing notes

For accurate output, print at 100 % scale - never "fit to page", which silently shrinks the sheet by 4–6 % and breaks every measured cell. Use a laser printer if the grid will be traced over with ink, since inkjet inks bleed through technical pen and pencil. If your printer cannot handle the full Letter sheet, scale the SVG to the next-smaller paper size before printing - every GridCraft grid is delivered as vector artwork so it scales cleanly. The downloaded SVG carries the physical sheet dimensions in millimetres, so a compliant print driver should print at 1:1 by default. Our how-to-print guide walks through the calibration test in 30 seconds.

Designer's note

Specialty grids reward the discipline of choosing the right sheet for the right drawing. A Semi-Log · 3 Decade on Letter is not a one-size-fits-all sheet - it's a calibrated tool for a specific class of problem. Use it where the page suits the drawing; reach for a different sheet when it doesn't. The catalogue is large precisely so you don't have to compromise on the projection, scale or sheet size.