- Download the utility called HexEdit, version 1.7.4 or later.
- Copy the .dfont that you want to your desktop, under OS 9. Copy a regular TrueType suitcase, say Capitals for example, to your desktop as well. Make sure these are copies, not the original.
- Using HexEdit, open the OS X .dfont file. Go to the Edit menu and choose Select All. Now use the Edit Menu and choose Copy.
- Open the TrueType font from your desktop (in my case Capitals) and do and Edit menu > Select All. Now do an Edit Menu > Paste.
- Now go to the File menu and Save. Close both files.
- To see if your conversion worked, double-click on the Capitals file on your desktop (there will be one called Capitals~, just ignore it, it is the original). You should see the individual cases now inside the font suitcase for each type of font style, for example, I converted Optima first, so I see Optima ExtraBlack, Optima, Optima (bold), Optima (italic), Optima (bold, italic) inside the suitcase. Double-click on one of the cases to see the preview, if the preview works the font is okay.
- Close the preview and font suitcase and rename the suitcase to match what is inside of it. Now place the suitcase in your System Folder, or Font Management folder where it belongs. Now you have the OS X font you wanted in Mac OS 9!
[Editor's note: I have not tried this myself, but it seems like a very useful tip! I would love to have access to a couple of the OS X fonts from Photoshop in Classic...]

