Interpolation — Dunbar Design Repository

Tools For Interpolation – An Interview with Erik van Blokland

Erik van Blokland and CJ Dunn | May 10, 2026

A conversation with Erik van Blokland about his history with interpolation technology, variable fonts, and font technology in general.

Tools For Interpolation – An Interview with Erik van Blokland

Seeds planted for variable fonts @ TypoLabs Berlin

Watched talk at TypoLabs in Berlin by Behdad Esfabod "Open Type GX : Bringing Font Variations to Open Type" showing proto-variable fonts

Reduced boldest stem weights for better contrast

Note: “*new_ultra is 80% between ultra and med” 🅢🅓

Fine tuning stem weights for each styles

Trying to work out the exact weights using interpolation and extrapolation in Superpolator app (by Erik van Blokland) and UFO Stretch (by Frederik Berlaen) and ScaleFast RoboFont plugin by Loïc Sander 🅢

Exploring x-height variations

Superpolator x-height tests “Dunbar xheight tests_1.5.sp3”