Don't use
fontName: fontName size: fontSize
as it only creates StrikeFont font, where the max size is 24 (I think).
This works ....
������ font := LogicalFont familyName: 'Open Sans' pointSize: 70.
������ tMorph := StringMorph new.
������ tMorph
������ ������ contents: 'Hello World';
������ ������ font: font;
������ ������ emphasis: TextEmphasis bold emphasisCode.
������ bMorph := Morph new
������ ������ color: Color red;
������ ������ addMorphBack: tMorph.
������ ������ bMorph bounds:(tMorph fullBounds).
������ bMorph openInHand
... but it seems we have a problem with the free type fonts (again).