This GIMP (GNU) tutorial demonstrates how to enliven a dull photograph by applying a rainbow Gradient to it. To work along, you are welcome to download the Start Image (Tynemouth) - I am working with Here. Unzip the file and open the image onto GIMP’s workspace.
You can quickly Undo a step at any time by pressing Ctrl then Z. Alternatively, click a previous Undo History snapshot - Windows then Dockable Dialogues then click Undo History. In addition, to Zoom in (or Zoom out) of your image; from the top menu, choose View then select a Zoom Tool from the subsequent drop-down list.
Understand Blend Modes
Launch GIMP & Organise Its Workspace & Palettes
Open your choice of Start Image onto GIMP’s workspace - File then Open - Ctrl then O.
Ensure the Layers and the Undo History Palettes are visible, and then drag them into position over your workspace - (Windows then Dockable Dialogues - then click Layers and Undo History).
Now, create a New Transparent Layer by clicking the following Create a New Layer tab that is located at the bottom-left of the Layers Palette. (Ctrl then N).
Then from the subsequent New Layer dialogue box, click OK.
Then from the left-side Toolbox, activate the Blend Tool.
And from the Blend Tool’s left-side Options Box, click open the Gradient Swatch, and from the subsequent drop-down Gradient Library, click over a Gradient you like the look of. I have selected the following Full Saturation Spectrum Gradient.
For personal results, experiment with different Gradients and Gradient Shapes.
Now, still working on the New Layer: press down the Ctrl Key and simultaneously left-click and stretch vertical “Gradient Line” in the direction illustrated below.
As soon as you release the mouse button, your choice of Gradient will be applied over your image.
5/ Understand Layers - Understand Blend Modes
From the Layers Palette; change the Rainbow Layer’s Blend Mode from Normal to Overlay.
For personal results, it’s important to experiment with different Blend Modes and discover a blend that suits your needs.
To finish, from the top menu, choose Image and then choose Flatten Image.
To create extra impact, apply a Sharpening Filter of your choice - Filters then Enhance.
Congratulations, your work is complete, and it is ready to save - top menu, then File then Save As. GIMP 2.8 - File then Export.
Now you are familiar with this technique, you can have lots of fun reviving dull photographs by applying a colourful gradient to them.
Wendi E. M. Scarth. Top of Page.