Bloom

Using Bloom, you can make a gradation of bright and dark areas on the screen. This post process brightens and blurs the light areas, but does not touch the dark ones. As a result, Bloom creates a glow effect in the Scene.

Bloom has 4 parameters: Intensity, Iterations, Threshold and Soft Threshold.

Intensity

When you increase the Intensity value, all the bright objects in the Scene begin to acquire a halo of glow. This glow is not real, in fact, the object does not glow. Go to the Edit mode, to verify this.

The Intensity parameter is responsible for the intensity of the entire post process, as well as for the blurring around bright objects and how much these objects will glow.

Iterations

The Iterations parameter is responsible for the number of blur iterations that our image is exposed to on the screen. This parameter enhances the effect of blurring on the image.

Note: If Intensity is 0 (minimum value), Iterations will not show anything, no matter how you increase or decrease it. Other parameters will not show anything either.

When Intensity equals 1 (maximum value), almost all colors in the Scene fall into the illumination range. Bright colors will become even brighter. The gray will turn into almost white.

And if the value of Iterations equals 5, it means that our image on the screen has passed 5 iterations of blurring. If we reduce Intensity, then we reduce the Intensity of the Bloom effect itself.

If we increase the Iteration value, then our image will undergo more blur iterations.

It is important to point out the difference between Intensity and Iterations: Intensity controls the intensity of the Bloom effect. The Iterations parameter is responsible for how many times this picture will be blurred. The greater the value of Iterations, the more the picture will be blurred.

Threshold

Threshold is responsible for the range of colors which the Bloom effect will be applied to.

When Threshold is 0 and Soft Threshold is 0, the entire color range (that is in the scene) participates in the blur effect.

If Threshold is 1 and Soft Threshold is 0, then no colors will blur, since we have removed all colors from our range.

Soft Threshold

Soft Threshold cuts off the colors that will participate in the Bloom effect.

Threshold and Soft Threshold are interrelated. They both are responsible for the color range that falls under the Bloom effect. Both parameters can be configured by entering values manually.

You can also use graphs to set values for Threshold and Soft Threshold by moving the graph lines. The graph is a color range control.