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Photo magic with Gimp

You are back from vacation and are going through all the georgeous photos that you have taken. But you notice that some photos would need a few changes to go from good to great. Time to open The Gimp and get creative! In this article I'll show you a few examples how you can improve on your photos. This is a revised version of an article I wrote some years ago. The latest stable version of the Gimp of the time of writing is 2.8.16.

[tux and camera]

Getting started

Open Gimp and just play around with it a bit to get a feel for the program. With file -> open you can open an existing image and with file -> new you can create a new one. You can change the width and height of the new image and if you click on advanced options you can decide if the background should be filled with the background color, the foreground color, or be white or transparent.

By clicking file -> create -> screenshot you can take a screenshot of e.g. a browser window.

By clicking images -> transform you can flip your image horizontally or vertically or rotate it 90 or 180 degrees. If you want to rotate it with a different angle you need to click on the rotation tool in the toolbox. Next click on the image and you can type in the desired degrees in the opening dialog box.

If you go to image -> mode -> grayscale you can make your image into a black and white image.

With image -> duplicate you can get a copy of your image. It is always a good idea to keep a copy of the original. Perhaps you won't like the changes that you made anymore next year or you want to try out something else. Then you will be glad to still have the original. So it's always better to save the changed photo under a slightly different name.
To try out several effects and compare them with each other it is also better to make one or several duplicates of your photo before you apply the canges to them.

Remember that often it is also possible to undo your lastest changes by pressing ctrl z.

Color Correction

Sometimes a photo looks a bit colorless, it is too light or too dark or there are other reasons why a color correction would help the photo. To improve the colors of your photos you can use the tools that you find in the menu under Colors (you find them in the menu on top of the image or by right clicking in the image that was opened with the Gimp).
Most of the time there will be a preview field that you can tick to make the changes viewable at once. If you click on Reset the changes won't affect your image and even if you already clicked "ok" you can still get your old image back by clicking crtl+z.

The Curves-Tool

If the photo is a bit too light or too dark you can work on it with the Curves-Tool (Colors->Curves). If you move the curve a bit up the photo gets a bit lighter and if you move it a bit down it gets darker. But you also have the possibility to change the color values of red, green and blue individually. Because of this the curves tool is very well suited to deal with color cast. In the example the shop in St.Tropez is a bit too blue:

[Shop in St. Tropez that is a bit too blue]
Fig.1 Shop in St. Tropez that is a bit too blue
[The shop in St. Tropez]
Fig.3 The shop in St. Tropez after using the curves-tool

The Levels-Tool

Some photos don't use the entire colour range. Therefore they tend to look a bit gray. That's the time for the levels tool. Often it will already be sufficient to go to Colors->Levels and click Auto. If you are not satisfied with the result you can also easily do it by hand. (You look at the curves and move the arrows so that the space at the ends isn't empty anymore. If Value is selected above the tool will be applied to the whole picture but you can also do it separately for each colour which often gives a better result. By moving the two arrows at the ends often the whole picture gets a bit darker which can be corrected by moving the arrow between them accordingly.)
You can also see if playing around with hue-saturation or brightness-contrast will enhance your photo.

[View from Mont St Alban in the Gaspé region]
Fig.4 View from Mont St Alban in the Gaspé region that looks a bid hazy
[View from Mont St Alban in the Gaspé region after working on the photo with Gimp]
Fig.5 View from Mont St Alban in the Gaspé region after Color-->Levels->Auto

Creating warmer looking photos and an evening atmosphere

If a photo is looking too cold it usually has too much blue in it. You can work on it with the curves tool like I did on the photo of the shop in St Tropez above. Another way is to use the Colors -> Color Balance and to move the sliders a bit towards yellow, magenta and red. You can also try Colors -> Hue- Saturation and move the sliders for blue and cyan a bit to the left and the other sliders a bit to the right. As every photo is different you really need to play around with the tools and values a bit.

To create the atmosphere of early evening you can also do this: Open a new layer (layer -> new layer)and fill it with an orange color (change the foreground color to orange, select all, then fill (by clicking on the bucket)). Then in the layers box choose mode overlay". You can adjust how strong the effect is with the opacity slider.

[At a lake in Muskoka]
Fig.6 At a lake in Muskoka
[At a lake in Muskoka with the atmosphere of early evening]
Abb.7 At a lake in Muskoka with the atmosphere of early evening after applying a new orange overlay layer to the original photo

Increasing the sharpness of your photo

It is not really possible to turn a photo that really is unsharp into a sharp and focused picture. Often it makes more sense to make an artistic photo out of it. But if your photo is only a tiny bit unsharp or became unsharp because of some tools you applied you can improve it by using filters -> unsharp mask (or filters -> sharpen). You have to play around with the values a bit. A good start for the unmask filter is to use radius 5, amount 0.5 and threshold 0.

[Black and white picture of row of houses in Liège]
Fig.10 Black and white picture of row of houses in Liège
[The row of houses after applying the Unsharp Mask]
Fig.11 The row of houses after applying the Unsharp Mask with radius 5, amount 0.5 and threshold 0
(You should only use these filters after you have applied all other changes as some tools (e.g. scaling of the photo) can change the sharpness of the image.)

For other artistic results you might want to play around with colors -> posterize, filters -> artistic -> GimPressionist, filters -> map -> e.g. illusion or fractal trace, filters -> artistic -> cartoon or any other options there. You will see that you can be an artist in no time. :)

Reducing the depth of focus

Sometimes it's difficult to take a picture with your digital camera that has the focus on the foreground and the object you focus on and a blurred background. Gimp can help you to reach this effect afterwards.
For this you select the part of the photo that you want to be sharp with the intelligent scissors (that's the tool in the toolbox that actually looks like a pair of scissors). You make some points around the object that you want to select. The intelligent scissors find the outline themselves. Therefore it is important to make more points in those areas where the object doesn't have a big contrast to its environment. To make the selection effective click on the first point that you made again, then you click somewhere inside your object. Now you can see the selection. Next you sharpen it a bit. For this you click on Filters->Enhance-> Unsharp Mask (e.g. radius 5 , amount 0.5, threshold 0) or Sharpen. After that you invert the selection (Select->Invert) and blur the background. To do this you go to Filters->Blur and choose the blur tool that you like best. Sometimes you won't like the transition between the sharp and blurred areas. In that case you can select the blur tool from the toolbox and draw around the outline as you would do with a paint brush.

[Bear with Jessica]
Fig.12 Bear with Jessica at the Fête des Enfants in Montreal
[Bear with Jessica with a blurred background]
Fig.13 Bear with Jessica at the Fête des Enfants in Montreal with a blurred background

Blurred vision: Soft looking photos and movement

With a non-digital camera you can get a soft looking image by using long shutter speeds. Of course you can create this effect with the Gimp afterwards. The blur tools can very well be used for this. The photo gets a softer look and may even look kind of romantic. Selective Gaussian Blur (Filters->Blur->Selective Gaussian Blur) is best to use here as the blur filter will only be applied to areas that don't have a big contrast.

[Kasteel Erenstein looking softer]
Fig.14 Kasteel Erenstein looking softer after applying Selective Gaussian Blur and a frame added with filters -> decor->Fuzzy Border and filters -> Decor-> add border. You can also turn your photos in a slide (filters-> decor ->slide) or into an old photo (filters -> decor ->old photo).

If you want to create an impression of movement the Motion Blur Filter (Filters->Blur->Motion Blur) will do best. The original looks like this:

[Tux in Oldtimer]
Fig.15 Tux in Oldtimer
You select the penguin in his race car with the intelligent scissors and invert select. And after applying Filters->Blur->Motion Blur with Linear as type of blur and with the Length 20 and Angle 45 you get this racing Tux:
[racing Tux in Oldtimer]
Fig.16 racing Tux in Oldtimer

When less is more: Removing "annoying" objects

One characteristic of a good photo is that is has a subject it focuses on and not so many other things to distract or confuse the viewer (except of course if this was in the intension of the photographer...).

So it can happen that one or more objects in an image disturb the overall impression of the picture and therefore it would be better to remove them. To do this you can use the clone tool (that's the button in the toolbox that looks like a stamp). If you have selected the clone tool you click with your mouse in the area that is to be cloned while you hold the Ctrl-key down.Then you release the key and click with the mouse in the area that you want to paint over. Now you can use the clone tool the same way you would use a paint brush. Sometimes you will get a more natural looking picture if you define a new cloning area several times. And practise makes perfect here!
Certain mistakes in a photo like a tree that grows out of a person can also be corrected this way.

[Photo of my grandfather]
Fig.17 Photo of my grandfather
[Photo of my grandfather after working on it with the clone tool]
Fig.18 Photo of my grandfather after working on it with the clone tool

Framing the photo

To get more focus and attention to your image you can give it a frame. Gimp offers numberous possibilities for this.

[Photo of fur trade museum in Lachine with a red frame]
Fig.19 Photo of fur trade museum in Lachine with a red frame

First of all you can give your photo an ordinary frame. For this you choose Filters -> Decor -> Add Border. Now you need to decide the width of the frame and its color. Then click on ok and The Gimp gives the picture a frame whereby the resulting size of the picture will be increased.

A very beautiful frame you get by using Filters -> Decor -> Fuzzy Border. This is actually my favourite frame. But of course everything depends on the motive of the photo.

[Flowers with Fuzzy Border]
Fig.20 Flowers with Fuzzy Border

Another possibility is to select that part of the image that you really want to see. After selecting it with the selection tool (the button that looks like a rectangle in the toolbox) you invert the selection (Select ->Invert) and change e.g. the lightness of the border (e.g. with the curves tool (color -> curves)),etc..

[Photo of St. Tropez with a lighter border]
Fig.21 Photo of St. Tropez with a lighter border

Inserting text

Sometimes a picture will only become something special or personal by adding some text at the right place. In the picture below the text was simply written over the name of the bridge that was hardly readable. With the color picker (that's the icon that looks like a pipette) the color of the decoration of the bridge was chosen. Then the font elfring elitelight was chosen in the text tool of Gimp and the text was inserted into the photo.

[Photo with inserted text]
Fig.22 Here is the photo that only became a special personal photo after inserting the text.

Of course The Gimp can't always do miracles and change a bad photo into a good looking one. And it's also not possible to write a cookbook with recipes for every photo as each tool has a different effect on different photos. But still I hope that this article will be useful for you to get the best out of your pictures!

Have fun and happy gimping! :)

Copyright © 2004-2019 Katja Socher, tuxgraphics.org