This is part of a tutorial on using the Bloom lens effect in LuxRender, a rendering engine that, in conjunction with Reality, can let you create highly detailed images.
Bloom is the fuzzy aura of light surrounding bright objects in photographs. It is a simple filter to use from the LuxRender menu. Look for it under “Lens Effects” on the rendering screen.
To use the bloom effect, select a radius and click the “Compute layer” button. It can take several seconds to calculate the image layer for the bloom effect. You must click the “Computer layer” button anytime you change the radius setting
Once the bloom effect layer is calculated, you can adjust the “Amount” parameter. The brightness of the bloom effect is controlled by the “Amount”. The higher the “Amount” setting, the more visible bloom’s foggy, glowing effect is. Changes in the “Amount” happen in real time; you do not need to recompute the layer each time.