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

### 5.4. Lighting Effects

#### 5.4.1. Overview

Figuur 16.98. 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

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.

General Options

  Figuur 16.99. “Lighting” filter 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.

Light

  Figuur 16.100. “Light” Options of the Lighting filter

  In this tab, you can set light parameters. With Light 1, 2,...6: You can create six light sources and work on each of them separately.

  Light Type

    This 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...).

  Light Source 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.

Material

  Figuur 16.101. “Material” tab of the Lighting filter

  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.

Bump Map

  Figuur 16.102. “Bumpmap” options of the Lighting filter

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

  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.

  Bump Map Image

    You have to select there the grey-scale image that will act as a bump map.

  Curve

    Four curve types are available: Linear, Logarithmic, Sinusoidal and Spherical. See Bump Map plug-in for explanations.

  Maximum Height

    This is the maximum height of bumps.

Environment Map

  Figuur 16.103. “Environment map” options

  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