The following screenshots illustrate the issue of autohinting thin stemmed webfonts for rendering with Windows OS ClearType using ttfautohint. The fonts used are Lato Light and Lato Hairline that have been auto-instructed using ttfautohint. A fix to this is expected soon.
(above – Lato Light. Windows GDI ClearType)
(above – Lato Light. Windows GDI Standard Smoothing)
(below – Lato Hairline. Windows GDI Standard Smoothing)
Note – whilst a font as thin stemmed as Laton Light renders ok at large px sizes, at smaller sizes the issue of pixel drop out appears, see below;