# Interpolation do I need stem widths?

**URL:** <https://forum.glyphsapp.com/t/interpolation-do-i-need-stem-widths/37246>\
**Category:** Glyphs\
**Created:** [September 9, 2026, 3:34pm UTC](https://forum.glyphsapp.com/t/interpolation-do-i-need-stem-widths/37246 "2026-09-09T15:34:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![itsmesimon](https://forum.glyphsapp.com/user_avatar/forum.glyphsapp.com/itsmesimon/32/34441_2.png) [@itsmesimon](https://forum.glyphsapp.com/u/itsmesimon)\
**Post date:** [September 9, 2026, 3:34pm UTC](https://forum.glyphsapp.com/t/interpolation-do-i-need-stem-widths/37246/1 "2026-09-09T15:34:34Z")

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I’m working on a variable font with two masters: Light and Bold, and it seems to be working okay. I hadn’t originally planned to interpolate between them, but now that I’ve done the work, I thought I might as well create, say, four weights as a standard typeface.

I’m not quite there yet, but do I need to enter stem widths in the Masters panel for interpolation to work correctly? The design deliberately uses different stem widths for almost every character, and I also have around eight stylistic alternates for each letter from A–Z.

 ![stems](https://forum.glyphsapp.com/uploads/default/original/3X/b/c/bcdd537caa320e693eba5434184f35b832a0f65d.png)

![animation](https://forum.glyphsapp.com/uploads/default/original/3X/3/d/3d62fdb54aef54da4e20b6736236afacf23cc374.gif)

Any help would be much appreciated.

Cheers

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**Author:** ![GeorgSeifert](https://forum.glyphsapp.com/user_avatar/forum.glyphsapp.com/georgseifert/32/259_2.png) [@GeorgSeifert](https://forum.glyphsapp.com/u/GeorgSeifert)\
**Post date:** [September 9, 2026, 9:08pm UTC](https://forum.glyphsapp.com/t/interpolation-do-i-need-stem-widths/37246/2 "2026-09-09T21:08:47Z")

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The stem values are used for hinting. Have nothing to do with interpolation. So If your drawing don’t need hinting, you don’t need stem values.

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<div class="post-metadata">

**Author:** ![itsmesimon](https://forum.glyphsapp.com/user_avatar/forum.glyphsapp.com/itsmesimon/32/34441_2.png) [@itsmesimon](https://forum.glyphsapp.com/u/itsmesimon)\
**Post date:** [September 9, 2026, 9:26pm UTC](https://forum.glyphsapp.com/t/interpolation-do-i-need-stem-widths/37246/3 "2026-09-09T21:26:22Z")

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Ah perfect, I’ll worry about it later then and continue finishing the two weights.

Thank you

Si