5.4. Lighting Effects
| 5. Light and Shadow Filters |

### 5.4. Lighting Effects

#### 5.4.1. Overview

Figure 17.99. The same image, before and after applying Lighting filter

Original image

Filter “Lighting Effects” applied

This filter simulates the effect you get when you light up a wall with a spot. It doesn't produce any drop shadows and, of course, doesn't reveal any new details in dark zones.

#### 5.4.2. Activate the filter

This filter is found in the image window menu under Filters → Light and Shadow → Lighting Effects.

#### 5.4.3. Options

Figure 17.100. “Lighting” filter options

Preview

  When Interactive is checked, parameter setting results are interactively displayed in preview without modifying the image until you click on OK button.

  If Interactive is not checked, changes are displayed in preview only when you click on the Update button. This option is useful with a slow computer.

Any other options are organized in tabs:

##### 5.4.3.1. General Options

Figure 17.101. “Lighting” filter options (General Options)

Transparent background

  Makes destination image transparent when bumpmap height is zero (height is zero in black areas of the bumpmapped image).

Create new image

  Creates a new image when applying filter.

High quality preview

  For quick CPU...

Distance

  You can specify the distance of the light source from the center of the image with this slider. The range of values is from 0.0 to 2.0.

##### 5.4.3.2. Light Settings

Figure 17.102. “Lighting” filter options (Light Settings)

In this tab, you can set light parameters. With Light 1 ... Light 6 you can create six light sources and work on each of them separately.

Type

  The filter provides several light types in a drop-down list:

  Point

    Displays a blue point at center of preview. You can click and drag it to move light all over the preview.

  Directional

    The blue point is linked to preview center by a line which indicates the direction of light.

  None

    This deletes the light source (light may persist...).

Color

  When you click on the color swatch, you bring a dialog up where you can select the light source color.

Intensity

  With this option, you can set light intensity.

Position

  Determines the light point position according to three coordinates: X coordinate for horizontal position, Y for vertical position, Z for source distance (the light darkens when distance increases). Values are from -1 to +1.

Direction

  This option should allow you to fix the light direction in its three X, Y and Z coordinates.

Isolate

  With this option, you can decide whether all light sources must appear in the Preview, or only the source you are working on.

Lighting preset

  You can save your settings with the Save and get them back later with the Open.

##### 5.4.3.3. Material Properties

Figure 17.103. “Lighting” filter options (Material Properties)

These options don't concern light itself, but light reflected by objects.

Small spheres, on both ends of the input boxes, represent the action of every option, from its minimum (on the left) to its maximum (on the right). Help pop ups are more useful.

Glowing

  With these option, you can set the amount of original color to show where no direct light falls.

Bright

  With this option, you can set the intensity of original color when hit directly by a light source.

Shiny

  This option controls how intense the highlight will be.

Polished

  With this option, higher values make the highlight more focused.

Metallic

  When this option is checked, surfaces look metallic.

##### 5.4.3.4. Bump Map

Figure 17.104. “Lighting” filter options (Bump Map)

In this tab, you can set filter options that give relief to the image. See Bump mapping .

Enable bump mapping

  With this option, bright parts of the image will appear raised and dark parts will appear depressed. The aspect depends on the light source position.

Bumpmap image

  You have to select there the grey-scale image that will act as a bump map. See Bump Map plug-in for additional explanations.

Curve

  This option defines the method that will be used when applying the bump map; that is, the bump height is a function of the specified curve. Four curve types are available: Linear, Logarithmic, Sinusoidal and Spherical.

Maximum height

  This is the maximum height of bumps.

##### 5.4.3.5. Environment Map

Figure 17.105. “Lighting” filter options (Environment Map)

Enable environment mapping

  When you check this box, the following option is enabled:

Environment image

  You have to select there a RGB image, present on your screen. Please note that for this option to work you should load another image with GIMP before using it.

  An example can be found at [BUDIG01].

5.3. Lens Flare |  | 5.5. Sparkle

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