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DTL OTMaster


DTL OTMaster 6

Examine and Fix OpenType Fonts. For Mac and Windows.

The technical OpenType editor

An affordable font utility that allows users to visually edit the contents of tables in TrueType and OpenType fonts. DTL OTMaster is here! It's a major advance in font proofing and table-editing for Mac and Windows.

DTL OTMaster (OTM) is a highly sophisticated application for reviewing, editing and altering tables and contours of OpenType fonts (.otf and .ttf), TrueType fonts (.ttf) and TrueType Collection (.ttc) fonts, including CID-keyed OpenType fonts, CJK (Chinese, Korean, Japanese) and complex-script (Indic, Arabic etc.) fonts, and all the competing color OpenType font extensions: Microsoft “COLR”/“CPAL”, Adobe “SVG ”, Apple “sbix”, and Google “CBDT”/“CBLC”.

OTMaster 6 adds:

  • Support for Retina displays
  • Opens TTC made by AFDKO
  • Open & export WOFF and WOFF2 font formats
  • Glyph editor has more tools
  • OTM Text Viewer supports metrics editing
  • Tool icon size can be changed (in preferences)

The Glyph Editor is a compact version of DTL FontMaster: it is a fully-featured outline editor, allowing you to edit a glyph outline, import a glyph from and export it to EPS or SVG (so you can modify it another app and bring it back). You can change the glyph’s metrics, apply various transformations, automatic outline improvement operations, and autohinting. (New: in OTMaster 6: more glyph editing tools).

OTMaster 6 also provides a flurry of more specialized tools:

  • The Font Viewer allows you to preview all glyphs in a font, from all outline points to the rendered bitmaps at various sizes.
  • The Side by Side Viewer allows you to compare glyphs across a number of opened fonts, while the Color Viewer, the Embedded Bitmap Viewer and the Glyph Viewer allow you to examine specific aspects of each glyph.
  • The Table Comparator and the Consistency Checker help you achieve consistent behavior of all fonts in a family or one font across different operating systems.
  • With the GSUB/GPOS Table Viewer and the kern Table Viewer, you can perform detailed examination and do small modifications of the font’s layout behavior: kerning, mark positioning, contextual, ligature and other substitutions etc.
  • The Text Viewer is a comprehensive test environment for OpenType Layout features. You can preview customized strings, enable features selectively, choose the text script and direction, and export the renderings to PDF. OTMaster 5 integrates the cutting-edge HarfBuzz OpenType Layout engine, allowing you to accurately test the shaping and rendering of complex scripts such as Arabic or Devanagari.
DTL OTMaster Specifications

Imports font formats: OpenType PS (.otf), OpenType TT/TrueType & Windows TrueType (.ttf), TrueType Collection (.ttc), Web Open Font Format 1 & 2(WOFF). Imports and compiles: Adobe FDK for OpenType (AFDKO) version 2.5 (.fea). Imports glyphs as: EPS, SVG. Also imports: URW++ character layout (.cha).

Export font formats: OpenType PS (.otf), OpenType TT/TrueType & Windows TrueType (.ttf), TrueType Collection (.ttc), Web Open Font Format 1 & 2(WOFF). Exports files: Adobe FDK for OpenType (AFDKO) version 2.5 (.fea), Adobe Font Metrics (.afm), URW++ character layout (.cha), URW++ font metadata (.ufm). Exports glyphs as: EPS, SVG.

Accessible Tables:  BASE, CFF , DSIG, GPOS, GSUB, OS/2, cmap, head, hhea, hmtx, maxp, name, post, LTSH, PCLT, VDMX, cvt, fpgm, glyf, hdmx, kern, loca, prep, gasp, GDEF, JSTF, EPAR

User manual: 106 pages, PDF

Hardware requirements: 1 GB RAM, 1024 x 768 or better screen, Mouse or trackpad

Software requirements: For Windows version: Microsoft Windows (XP/Vista/7/8/10). For Mac version: Mac OS X (10.7 or higher).

60 day money-back guarantee

DTL OTMaster Reviews and Testimonials

DTL OTMaster is a tool for cracking open and looking inside OpenType fonts (or plain old Windows TrueType fonts). It shows a fairly literal/direct representation of what?s in the various tables and subtables. It has an unobtrusive interface and allows direct editing of various fields. Why would I use OTMaster instead of FontLab Studio 5? FLS is a great program which I use a lot, but it interprets the OpenType font into its own internal format. It can?t open a font, make a tiny change and re-save it as a font without potentially changing other things... So tools like DTL OTMaster are really handy for that, because they show the unvarnished truth of what?s in the font, without interpretation.
Thomas Phinney, Phinney on Fonts

DTL OTMaster is a diagnostic tool, and it lets you do surgery. I sometimes need to perform post-production operations on font data, because in my workflow, the OpenType font file (.otf or .ttf) becomes the source format for OpenType Layout and hinting work. But even if one has a workflow in which a program like FontLab Studio remains the source format throughout, up to the point of final font generation, OTMaster is useful as a means of examining generated fonts, quality assurance.
John Hudson, Type designer and partner at Tiro Typeworks

As someone who works with OpenType fonts on an every-day basis, and with the tools that are used to build and check them, I would like to state here that DTL OTMaster is a fabulous tool. The best way for me to characterize it is that it gives me the power of some existing command-line tools, wrapped up in nice GUI. It handles CJK fonts well, including those with a large number of glyphs. I especially appreciate that there is a Mac OS X version.
Dr. Ken Lunde, Sr. Computer Scientist at Adobe Systems

Purchase DTL OTMaster

Full version purchases are completely automated. For upgrades and academic orders, it takes up to a day to process an order. During North American business hours, usually we can get it done within a few hours and you will receive your serial number the same day. Occasionally it won't be until the next business day. Upgrades will require your serial number or identifying your previous purchase details.

Mac version for Mac OS X 10.7+. Windows version for Windows XP and later

Full Version

DTL OTMaster 6 USD $310


Academic Full Version

DTL OTMaster 6 USD $155.00



DTL OTMaster 6 USD $61.40
If you purchased an earlier version from FontLab, pay online above, then email orders at fontlab.com with your serial number and version.



The DTL OTMaster 6 user manual is included in your purchase download. To view it in advance, you may download the user manual (PDF format, English) directly.

Development, License & Support

DTL OTMaster was jointly developed by Dutch Type Library and URW++, and is now available on fontlab.com. The product is subject to Dutch Type Library's license agreement, and technical support is provided by the DTL.