font becomes gray after saving

[avrob]

I'm new in font editing. I use TypeLight 3.2.

There is a font and I want to change some glyphs there.

My OS is WinXP.
When in display properties -> Appearance -> Effects..

"Use the following method to smooth edges of screen font" is checked and "Standard" method is selected then

after making changes (even if the change is insignificant) and saving the font the changed letters become gray while unchanged letters are still dark. It is well seen in Word processor.

When "Use the following method to smooth edges of screen font" is unchecked all the letters after saving the font are black.

What is being changed in the font that makes it gray and what is the reason of such behavior ?

[Allan Murray]

When you edit a character, the 'hinting' for that glyph is lost. Hinting instructions are contained in some fonts to adjust how the glyph will be displayed at low screen resolutions*. Here are a couple of links with a more detailed explaination:
www.typotheque.com/articles/hinting
www.smashingmagazine.com/2012/04/24/a-closer-look-at-font-rendering/

If you look at the section 'Hinting' in the demo versions manual (page 25), it shows how you can use free auto-hinters to apply new hinting to a font. You can also remove all hinting from a font by unchecking the 'hinting' box in Font/Font options menu before saving your font.

*Note that loosing hinting will not affect how the glyphs look when printed, only how they look on the screen - especially at small font sizes.