Transparency is a graphical effect used in visualizations to present co-located graphical glyphs. Accomplishinga visually convincing transparency effect requires complex calculations of light absorption andrefraction in object space. Alternatively, screen-space sorted rendering of graphical primitives using colour-blending techniques can be used for interactive applications. In this paper an efficient way is presentedto render transparent glyphs for information visualization. The technique combines random dotsurface plots with pre-computed transparent shape impostors to present different levels of transparencyfor co-located graphical glyphs. It is shown that this rendering method is faster than ordered polygonrendering using blending.