This GIMP (GNU) tutorial demonstrates how to Improve Digital Photographs using four Filters. To work along, you are welcome to download the Start Image I am working with Here. Unzip the file and open the image onto GIMP’s workspace.
Each photograph is unique, and therefore has different needs. With this in mind, when working with your image, it’s important to experiment with the settings outlined in this tutorial.
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.
Improve Scanned Photographs Using Three Filters
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).
The Adjustment Curves Editor is possibly the best way to adjust the brightness of photographs: - it affords a sophisticated way of deciding what the impact value of a pixel should be adjusted to either by adjusting the combined RGB channels together, or by adjusting individual channels. Where brightness control simply adds a number to each pixel, and each channel without order; the Curves command can for example, increase or reduce the values of pixels in a non-linear fashion, and as a consequence, the middle values are adjusted leaving the extremes unaffected. This is how Curves can darken/lighten an image whilst leaving those colours close to solid black, and solid white, unaffected.
2/ The Curves Editor
Now, from the top menu, choose Colours and then choose Curves. And from the subsequent Curves dialogue box, create a gentle S Curve. To create an S Curve,
left-click to apply two Points along the diagonal line (curve adjustment line) - as illustrated below.
(Don’t click OK).
Now, left-click over the left-side Point - and then gently drag it slightly downwards - as illustrated below. Then release the left-mouse button.
(Don’t click OK).
Now, left-click over the right-side Point, and drag it slightly upwards - as illustrated below. Then release the left-side mouse button.
Then click OK to commit the S Shaped Curve. Congratulations, you have created a gentle S Curve.
For personal results, take a little time to experiment with the Curves Editor.
3/ The Levels Editor
From the top menu, choose Colours and then choose Levels. And from the subsequent Levels dialogue box, grab the White Point tab, and drag it a little to the left - as illustrated below.
The Levels Editor provides features similar to the Histogram Editor but can also change the intensity range of the Active Layer or Selection in every channel. This Editor is used to make an image lighter or darker, to change contrast - or to correct a predominant colour cast.
Adjusting the White Point brightens your image’s white areas - as illustrated below.
(The Black Point slider darkens dark pixels, and the Gamma (Grey) slider adjusts your image’s Midtones).
For personal results, take a little time to experiment with the Levels Editor.
4/ Sharpening Filter
Now, from the top menu, choose Filters then choose Enhance and then choose Unsharp Mask. And from the subsequent Unsharp Mask dialogue box, experiment with the Radius, Amount and Threshold settings, and then click OK.
Sharpen Images Tutorial
For personal results, take a little time to experiment with GIMPs Sharpening Filters.
5/ Hue-Saturaton Editor (Add Warmth)
From the top menu, choose Colours and then choose Hue-Saturation. And from the Hue-Saturation dialogue box, move just the Saturation slider a little to the right - as illustrated below, and then click OK.
This warms your image’s colours - as illustrated below.
For personal results, take a little time to experiment with the Saturation Slider.
Congratulations, your work is complete, and it is ready to save - top menu, then File then Save As.
Important: Save As
To preserve your original photograph, always choose Save As, as opposed to Save.
My four-step photo fix principle works well in most situations, however, for personal results, it’s important to experiment with the Tools, Filters and Commands that GIMP offers, and discover the best steps for your photograph’s requirements. And don’t forget the importance of the Crop Tool: cropping away distracting elements can dramatically improve your photographs. (Crop Tool Tutorial).
Wendi E. M. Scarth. Top of Page.