"Alpha Blending. This setting can be used to enable/disable dither
subtraction on the Destination colour during Alpha-Blending. When dither
subtraction is enabled, the dither matrix used to convert 24-bit colour to
16-bit colour is subtracted from the destination colour before applying the
alpha-blending algorithm. Setting this to Automatic will allow the
application in question to use dither subtraction as necessary. Setting it
to Sharper will enable dither subtraction, resulting in a sharper image.
Setting it to Smoother will disable dither subtraction, resulting in a
smoother image. I'd recommend setting this to Sharper.
NOTE - Setting 3D Filter Quality to High & Alpha Blending to Sharper will
enable the use of a special post filter which results in effectively 22-bit
colour. This will provide optimal image quality with the Voodoo 3."
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