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DTL OTMaster


DTL OTMaster 3.7

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 (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-scripts (Indic, Arabic etc.) fonts.

Version 3.7 improvements

Working with multiple fonts

  • NEW! Compare glyphs across all open fonts with the new Side by Side Viewer tool
  • NEW! Easily compare and edit font parameters across all open fonts with the new Table Comparator tool (tables: head, hhea, vhea, OS/2, maxp, post header, CFF top dict, PCLT)
  • IMPROVED! Easily jump to the same table location across all open fonts with the Next File Above and Next File Below keyboard shortcuts

Updated font format support

  • NEW! View and edit the new Microsoft color font format (COLR+CPAL tables) with the new Color Viewer tool
  • NEW! Edit the optical size range parameter in OS/2 table version 5
  • NEW! Import/export Ideographic Variation Sequences (IVS) for CJK fonts
  • NEW! Export URW++ font formats
  • IMPROVED! Detect name table problems in the improved Consistency Checker tool
  • NEW! Enable/disable subroutinization of the CFF table in Preferences

Revamped Glyph Editor tool

  • NEW! Detect and automatically fix glyph outline problems with the new Inflections and Flat Curves highlighting and the new Improve tool
  • NEW! Reverse overlap removal with the new Disconnector tools (X and I)
  • NEW! New Measure, Grid, Guidelines tools
  • NEW! Glyph clipboard library
  • IMPROVED! Enhanced background layer handling

To upgrade to DTL OTMaster 3.7 from older versions (EUR 50), e-mail us at This e-mail address is being protected from spam bots, you need JavaScript enabled to view it


DTL OTMaster: glyph viewer DTL OTMaster: GSUB/GPOS viewer, GSUB table, Image view
Click on a thumbnail to see the full screenshot. See more screenshots...


Introduction to DTL OTMaster on Vimeo
Click on the thumbnail to see a short video introducing DTL OTMaster or open it on Vimeo.


DTL OTMaster reveals the secrets of your OpenType and TrueType fonts without your having to slog through text dumps or binary code. It makes the editing of tables easy and smooth using its graphical user interface.

Furthermore, it comes with a built-in Glyph Editor for proofing and editing contours or even drawing glyphs from scratch. The kern Table Viewer provides a kerning class editor for proofing and refining the kerning, and the GSUB/GPOS Table Viewer lets you visually test (and in case of GPOS also adjust) these OpenType Layout tables.

One of the most remarkable functions in OTM, is the option to import and export OpenType Layout features files. During import OTM compiles the OpenType Layout features with the AFDKO (Adobe Font Development Kit for OpenType) syntax (.fea) and produces binary OpenType Layout tables.

DTL OTMaster - the technical OpenType editor. A perfect font tool for professional font users, type designers, as well as software vendors and developers.

DTL OTMaster: Overview
Click above to see a screenshot of DTL OTMaster.

In-depth, non-invasive

Examine, report, print

Why does your Euro character keep turning up in the wrong place like a tuxedo at a Halloween party? Maybe he got lost because of a lousy cmap? Check it out with OTM's table viewer and get him to the wedding on time.

DTL OTMaster (OTM) is an excellent tool for looking deep into an OpenType font?s hidden treasures. More...

Add, copy or edit a glyph

Your client's specified font has an ampersand that looks like pig's entrails. No need to haul out the meat cleaver big font editor. A little judicious surgery with OTM's glyph editor can solve the problem in minutes.

When the font you?re using is missing a glyph or an existing glyph has an inappropriate shape, OTM allows you to fix this without breaking or changing the font?s original hinting, kerning, or OpenType Layout features. More...

Test and edit OpenType Layout features

If you've cooked up or discovered a recipe for a great feature set you don't want it to disappear after you've served it up just once. Keep the formula around for future font feasts by exporting a .fea file from OTM.

Swashes, small caps, marks, cursive attachment - what's going on?  More...

Fix families, linespacing, encoding

Your pretty swash font looks like it got a buzzcut: the tall glyphs are all clipped at the top. Like a bad part the linespacing is different on Mac and Windows? Or you wanted an Afro but the font appears in the font section for Greek fonts, although it includes only two Greek letters? The Light style appears after the Regular style in the font menu, or does not appear at all? More...

Last-minute adjustments

Your OpenType font is perfect, but... Oops, you've forgotten to update the version string. Or there's an OpenType glyph that you'd like to access directly from the keyboard. Or the font's underline is too thin. Or the font's antialiasing is not quite like you'd like it to be. OTM lets you perform last-minute changes without you needing to rebuild the font from sources - great, especially if you have a complex production workflow. More...

Is it the font? Is it the app?

If you're a software developer or vendor, DTL OTMaster will allow you to examine fonts and identify whether the problem is caused by a buggy font, or by buggy software. Developed with globalization and internationalization in mind, OTM provides deep insight into the state-of-the art Unicode-based OpenType / ISO/IEC 14496-22 font technology.

DTL OTMaster Specifications

Imports font formats: OpenType PS (.otf), OpenType TT/TrueType & Windows TrueType (.ttf), TrueType Collection (.ttc). 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). 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: 84 pages, PDF

Hardware requirements: 512MB RAM, SVGA monitor, Mouse

Software requirements: For Windows version: Microsoft Windows (2000/XP/Vista/7). For Mac version: Mac OS X (10.6 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

It takes up to a day to process an order. 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.

Macintosh OS X

DTL OTMaster 3.7  EUR €255.00 Convert the price into another currency
Mac version for Mac OS X 10.6+.


Bundle: DTL OTMaster 3.7 PLUS Fontographer 5.2  US $689.00 Convert the price into another currency


DTL OTMaster 3.7  EUR €255.00  Convert the price into another currency

Bundle: DTL OTMaster 3.7 PLUS Fontographer 5.2 US $689.00  Convert the price into another currency

Download user manual for DTL OTMaster 2.4 (PDF format) by right-clicking or Ctrl+clicking one of these links and choosing "Save link as" or "Download linked file":

Download English manual: US1 | EU

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. The technical support will be provided by the software's vendor.