In this quick tutorial we’ll colour correct a bad photograph. But, first things first:
What on earth is GIMP?
GIMP is a free, open source, image manipulation tool which runs on Windows and Linux. Think of it as a (genuinely!) free version of Adobe Photoshop. Many people think GIMP isn’t as powerful as Photoshop, they’re wrong. If Photoshop can do it, GIMP can do it. Grab GIMP from: http://gimp.org
GIMP is installed, now what?
OK, here’s out starting image:
A purposely bad photograph that we can easily fix. Well, it’s pretty obvious that it’s kinda blurry and it’s not exactly bursting with colour. But we’ll fix that.
First, go to the menu and click Colours > Levels and you’ll see the Colour Levels window. The first thing to notice is the three triangular markers, which I’ve marked with red arrows on the diagram below, which denote dark (black triangle on the left), medium (grey, in the middle) and light (white, on the right).
The black graph above the red arrows (that I added) is a graph of the images colour levels. The fact that there’s a gap between the left and right of the graph means that the dark and light levels of the image are out. To fix this, we can drag the black and the white triangles to where the graph starts and ends. Keep an eye on your image as it will change as you drag the triangles. Mine looks pretty good set like this:
I’ve marked on the diagram (above) where I dragged the arrows from and to. So, now my image looks like this:
Not bad! If you want, you could click on Colour > Levels again and drag the grey triangle too, but I reckon it looks OK as is. Only thing is, it’s still quite blurry.
To fix the blur, click Filters > Enhance > Sharpen and you’ll get a new window with a slider. This will let you sharpen the image while getting a preview. If the preview window isn’t updating, make sure the ‘Preview’ box (in this new window) is ticked. After ramping the slider up to about 75, the preview looks good and I’m left with:
Which I’m sure you’ll agree, is far better than the starting image. So it goes to show that even the worst of images can be fixed!
Next, I’ll write a tutorial on fixing distorted perspectives (again, in GIMP) which often happens when taking a photo of a painting. This will make your painting fill the screen and not look smaller on one side than on the other!