Two Basic Tips For Using Digital Lighting Effects In “GIMP” (GNU Image Manipulation Program)

Well, it’s been a while since I wrote an art-related article. So, I thought that I’d offer a few tips about using the digital lighting effects in a free, open-source image editing program called “GIMP” (GNU Image Manipulation Program). This free open-source program is also compatible with pretty much every major operating system too.

For this article, I’ll be using version 2.8.22 of GIMP, since I had to re-download GIMP following some technical problems with my computer. However, the process is pretty much the same for slightly older versions of GIMP and is probably similar or identical for newer versions too.

Anyway, I’ve decided to write about digital lighting effects since I seem to have used them in a few of my more recent paintings, like this one:

“1999” By C. A. Brown

So, here are two tips/tutorials for using the digital lighting effects in GIMP.

In both tutorials, I’ll be adding artificial lighting (and then making it look more realistic) to this old “1980s cyberpunk”-style painting of mine from a few months ago.

1) The basics: First of all, open your image in GIMP and then look in the “filters” menu at the top of the screen. Look for the option called “Light and Shadow” and then select “lighting effects”. Like this:

How to get to the lighting effects menu in GIMP 2.8.22

Once you’ve done this, you’ll end up with a menu that shows your image with a blue dot that represents the new light source. Click and drag the dot until the light source is where you want it to be:

Click and drag the blue dot (in the small picture) until the light source is where you want it to be.

Once you’ve done this, then click the tab at the top of the menu called “Light”. From here you can fine tune the light’s position (by altering the X, Y and Z values), alter the type of light, alter the intensity of the light and also change the colour of the light (by clicking on the bar next to the “color” option, like this):

You can change the colour of the light by clicking on the bar next to the “color” option.

After this, you can also select the “Material” tab and alter the properties of the light in more detail (eg: how bright you want it to be, how much you want it to glow, shine etc..).

Messing around with the “Material” settings in order to give the new light source more of a glow.

Although there are a couple of more advanced options (eg: bump mapping, environment mapping etc..) available, we’ll ignore these. So, click “ok” and your new lighting effect should be applied to your image – like this:

Voila! Atmospheric red lighting 🙂 But, we aren’t finished yet….

2) Making it look more realistic: Although the digital lighting effects in GIMP do a good job at simulating how a new light source affects everything else in the picture, they can only apply these effects to the image in a two-dimensional space (since all images are 2D).

The way that the effect works also means that a lot of your image will be darkened too (to make the new light source look brighter by comparison). So, if you want to make your new lighting look more realistic (eg: 3D), then you are going to have to do this manually.

There are two ways to do this. One is to to have a good grasp of realistic lighting and shading, and to add the required shadows etc… to your art before you apply the effects. But, if you haven’t done this, then there is an easier way to do this. So, let’s get started…

Use the “free select” tool (the icon looks like a loop of rope) to select an area of your picture that is facing towards the light source:

Using the free select tool from the menu, I’ve selected part of the picture (one side of the TV aerial and one side of the crow) that is facing towards the light source.

Once you’ve done this, go into the “colors” menu at the top of the screen and select “Brightness – Contrast”, like this:

The brightness & contrast option.

Once you’ve done this, move the sliders until the area you have selected is lighter than it previously was. Like this:

Notice how the side of the TV aerial facing the light source now looks brighter than it used to.

If you are using coloured light (like the red light in this example), then you can make your picture more realistic by going into the “colors” menu again and selecting the option called ‘Colorize’.

Once you’ve done this, increase the saturation level and then keep moving the “hue” slider until the selected colour is the same colour as the light source. Like this:

Adding some colour to the brighter area, by altering the “hue” and “saturation” settings.

After this, just repeat the process where necessary and your picture will look a little bit more “3D”. Like this:

Voila!

—————-

Anyway, I hope that this was useful 🙂

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