How to edit your photos with GIMP

GIMP is an acronym for GNU Image Manipulation Program. It is a freely distributed program for tasks such as photo retouching, image composition and image authoring.

The recent digital cameras are becoming more intelligent. Full of programs for analysis and treatment, they are able to adapt to a scene to photograph with the optimal settings. These PDAs can even correct, alone, without having to go through a computer, some small defects: red eye, contrast, etc..

But if all these automatisms are often effective, they are not miraculous and resist their images. These photos deemed unsuccessful and that we would be tempted to slip into the trash, are not permanently lost. With a good software for editing images, a little patience and technique, it is possible to save the most.

GIMP is expandable and extensible. It is designed to be augmented with plug-ins and extensions to do just about anything. The advanced scripting interface allows everything from the simplest task to the most complex image manipulation procedures to be easily scripted.

The error is human

The most common errors are often of human origin. An oversight in the settings, framing a bit fast and then disappointment the horizon is flawed, the composition is not balanced, the colors are fantastic, it's too dark or overexposed, blurry, etc.. In this case, we will show you how to fix in a few mouse clicks, the most common errors. It will also be an opportunity to explain why a picture is missed, to recall some basic rules of photography and to specify what he would have been good to do at the time of the shooting to avoid any work of editing .

Almost all images can be corrected, if you have time to devote. One case, however, is resistant to almost all forms of treatment: the picture blurred. It depends on the blur: if it is light, one can artificially enhance the impression of sharpness, and the photo will be used for printing in small format. However, an important blur is unrecoverable, then think about it when you take your shots.

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Download GIMP 2.6.6 from FTP: ftp://ftp.gimp.org/pub/gimp/v2.6/

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A horizon through, and the whole image seems to break the figure. To avoid this, just take your time when shooting. Try to ensure that the horizon is parallel to the edge of the LCD screen when you are targeting.

Remember to use the wizards of your camera. For example, the grids that appear on the screen can help you achieve your compositions.

Otherwise, there are many ways to straighten the horizon with The Gimp. One of the simplest is through the measurement of the angle of rotation of the image. Start by opening the photo to correct the menu File -> Open or the applicant simply on the window image editor Gimp.

Step 1: Measure the angle of rotation

In the Toolbox window, click Measurement Tool symbolized by a compass or press Ctrl + M. In the tool options, select the Use the info window. Position yourself now on the image and draw a line along the horizon line. In the dialog box that appears, lift the angular measurement in degrees. In our image, the horizon leans to the left of 2°.

Step 2: Rotate the picture

1. Make sure you now have the rotation tool. In the tool options in the menu Cropping, choose "Crop according to the same report" to keep the ratio of original image and leave other parameters unchanged.
   
2. Click on your image, a dialog appears with the parameters of rotation. In the Angle box, enter the angle noted above. If your horizon looks right, the value shown will be negative, if it leans left, it will be positive. For our example, this will be -2. Press the Enter key, then click Rotate. The image is cropped and adjusted on a transparent background checkerboard. Go to the Image menu, then click Resize canvas to layers to eliminate it.

Step 3: Save the image

Go to the Image menu, select Flatten Image to remove the alpha channel (transparency), created by The Gimp in the cropping and unmanaged by the Jpeg format. To save the result, go to the File menu, then click Save or press Ctrl + S. In the dialog box that appears, check the Show Preview in image window to get an estimate weight Jpeg file.

If you want to keep the best quality possible, move the cursor to 100. For a good compromise between image quality and weight of the file, choose a value between 80 and 90. Confirm by clicking Save.

Crop an image

The framing is an essential aspect of the picture. It highlights an element, the composition more dynamic and guide the viewer.

One of the classic rules of composition is that of third parties. It divides the image into three horizontal stripes and vertical field, forming a grid of four lines of force. We rely on these lines to structure the image with a ratio of two thirds to one third in avoiding the topic of focus.

In the case of a landscape, for example, leave a third of the sky for two thirds of land, or vice versa if you want the sky to highlight. The four intersections of the lines of force are the strengths on which we place the important elements. In our example, the subject (a bird) is too centered and distant. We are going to crop the photo so that it is better developed.

Step 1: Set the cutting tool

1. Open your image and you carry the tool represented by a cutting blade cutter. In the tool options in the first drop-down menu, select Proportions and check the Set to crop your image by keeping the same ratio.
   
   In the box just below, you can specify the ratio of your choice. The default is that of the current image applies. To change it, enter a fraction, for example 3:2 ratio for standard photo format, 4:3 to that of compact digital for a 1:1 square format or 16:9 image to fit your format your HDTV. Click on the small icons on the phone to change the ratio and switch from portrait to landscape.
   
2. In the tool options, check "Setting highlights". It helps to darken the image area to be cropped by the cropping and better judge the effect. Directly across from the dropdown menu, select "Rules others" to view a grid support frame according to the principles mentioned earlier.

Step 2: Crop the photo

1. To eliminate the parasitic elements and we approach the subject, we will make an important crop. Left click on the image and drag the mouse keeping your finger pressed to expand and shrink the crop grid and release the click.
   
   If you are not satisfied, click again within the framework holding the finger pressed to move it. You can also use the arrow keys on the keyboard. To change the size, enter one of the squares in each corner of the frame and stretch it by dragging the mouse.
   
2. Place the bird's head on a point in the third left of the image. One click automatically short crop. You can always cancel your crop in the "Undo History" tab of the Layers window.
   
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   Note
   this is indicated at the top of the image - that our picture is cropped more than 1911 x 2866 pixels or about 5.5 Mpix instead of 12 Mpix departure. It is enough for display on screen or for printing in small format (10 x 15 cm to A4, even a little more), but not enough for major expansions.

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3. Save by going to the File menu, then Save As and rename your new image to avoid overwriting the original.

Remove red eye

The red-eye phenomenon appears when using a flash. It is the reflection of light on the retina of the eye. To avoid this, the cameras incorporate anti-red eye, preflashs of which will cause a contraction of the pupils and reduce the passage of light.

Some are effective but do not, and to completely eliminate the problem, the only solution is to avoid direct lighting using, for example, an external flash. You can also do without the flash by increasing the ISO sensitivity, which also makes it possible to keep the ambient light and to avoid shadows, generally unsightly.

Step 1: Select the eyes

1. To correct red eye, we will conduct a selective modification of the image with the elliptical selection tool. Zoom in on the first eye to be treated using the "+" key on the numeric keypad. To move around in the zoomed image, press the Spacebar on the keyboard down and drag the mouse cursor.
   
2. With the elliptical selection tool, draw a circle to isolate the red pupil. You can move the selection with support for the left click on your selection. If the pupil is not perfectly round, you can change the form by clicking on the edges of the rectangle around the circle selection. An arrow appears, drag the circle and turn it into oval using the mouse.

Step 2: Change the color

1. The Gimp offers a filter for automatic red-eye. Once you have made your selection, go to Filter menu, then click Remove Improvement and red eyes. In the dialog box that appears, move the slider to eliminate as much red, and then click OK.
   
2. If the correction seems too violent, you can refine it by changing the hue, saturation and brightness of the dialog Hue-Saturation in the Color menu. When you're satisfied, delete the selection in the Select menu, then click None.
   
3. For the new ward that fits well into the eye and does not seem too stuck, use the drop slightly to flout the border between the iris and the pupil. In the settings of the tool, choose a soft edge brush (Circle Fuzzy) a small diameter with an average opacity.
   
   When you're done, you do not have to worry about the other eye in the same way. Finish by going to the Image menu on Flatten Image. Then save your work.

Improve exposure

Sometimes, a picture may appear too dark or too bright with dull colors. Several causes are possible. This may be due to a lack of light or against a light too violent, against a day or a bad camera settings. If you have the opportunity, try to make your shots at times when the light is softer, the morning or evening instead of midday, especially in summer when the sun has a violent lighting without subtlety.

Defects correct exposure is relatively easy as they are moderate. In cases of severe overexposure, we talk about image burned or, in the case of an under-exposure, image bite. Some information is missing, and even as being one of the editing, you can not do much.

Step 1: Correct Levels

1. The bar that you can view by going to the Window menu, then in dockable windows is a graph showing the distribution of information of an image. On the left, you have the dark tones in the center and midtones, right, clear tones.
   
   In our example image (a tree in bloom), all information is concentrated on the left and the curve is completely flat on the right which indicates an under-exposure. We will correct it by adjusting the levels. Note that the handling is identical for overexposure, it's just that a histogram is inverted with a failure of information to the left of the curve.
   
2. Use the Level Colors in the menu that lets you modify the histogram. Grab the little white slider below the histogram to the right and move it to the level where the curve ends of the histogram. Then take the midtones slider and move it a little to the left. Our image is more presentable, but lacks a bit of tone.

Step 2: Give a little peps

To wake up a little contrast, we use the curves in the Colors menu. In the window, you see, in gray, the histogram of a curve crossed diagonally. Enter the curve at the top in the area corresponding to the clear tone and stretch it slightly upwards. In the lower part, corresponding to dark tones, do the opposite, in order to obtain a final shaped curve S.

This can be applied to all your images to energize and strengthen the reported contrasts. You can also use the Brightness Contrast menu colors to accentuate. When you are satisfied with the settings, you can check the histogram with the curve now information on almost its entire length.

Remove one dominant color

In some cases, a picture can make a significant color cast. This happens often with photographs taken under artificial light (indoor) with a dominant orange. This problem is caused by a bad white (white balance), which distorts the color temperature.

To avoid this problem, your camera offers presets for different types of lighting: sun to daylight for tungsten filament lamps, etc.. Consider choosing one of these modes depending on the situation, it is often more efficient than automatic mode. On some devices, you can also measure the white balance manually by placing a white surface, the more neutral as possible, before the goal, such as a sheet of paper.

Solution 1: Retouching express

Gimp offers a very effective tool to correct the white balance. To find it, go to the Colors menu, then in Auto and finally in White Balance. This automatic feature is very effective and, in 90% of cases, it will resolve with a single click, your dominant problems. For the remaining 10%, you will have a manual setting.

Solution 2: Measurement Manual

1. To correct the orange of a portrait, we will use the level that is in the Colors menu. In the dialog box, you notice at the bottom, three pipettes. They are used to measure the white, gray and black point of an image. Start by clicking the eyedropper Whitepoint. Find the image in an area supposed to be white and click with the eyedropper. For more details, zoom with the "+" key on the numeric keypad and scroll around the image by holding down the Spacebar on the keyboard.
   
   When you find your white point, here in the foliage of the background with you in the Black Point eyedropper and now looking for a black image, the pupil of the eye of the girl for example. Made several attempts until you get a satisfactory result. Then click OK.
   
2. The correction has improved the image, but it remains a dominant orange light. To eliminate completely, it remains to find the gray. Reopen the Levels dialog box, select the gray eyedropper and put you in search of an area that should be in the final image to a gray, as neutral as possible.
   
   As previously, trial and error to get a convincing result, and then apply the settings by clicking OK. The corrected image was found in natural colors, save by pressing Ctrl + S.

Delete unwanted items

Despite all of your talents as a photographer, outside factors, disruptive, can come to spoil your images. Tourists and electric pollute the landscape, waste abandoned on a beach immaculate, buttons or the imperfections on a face or just dust on the sensor of your camera or on a poorly cleaned.

The advantage with digital is that you can cheat, and that with a little patience, it is easy enough to clean a picture of all these troublesome elements.

Step 1: Prepare the cloning tool

1. A landscape postcard (an idyllic beach with a fishing boat) would probably be even more heavenly without waste on the white sand and tourists. Do not worry, we will in a few clicks get rid of it. For this, we use the cloning tool, which is denoted by an icon shaped stamp which can duplicate parts of an image to copy them to another place.
   
2. To clone a portion of the image that we named source, just click above by holding down the Ctrl key. Go on then where you want the copy, the destination, and click again, it's magic! If you move the mouse click now supported, the source moves parallel to the destination. Proceeding by successive clicks, you always clone from the same source.
   
3. To delete the pieces of wood and plastic bags that litter the sand, set a hard brush (Circle) with a diameter slightly greater than the object to remove and with an opacity of 100%. Zoom in and click on the virgin sand near by holding the Ctrl key to identify a source. Click on the item to delete and, without releasing the click, drag it to buffer the blur.

Step 2: Disappear tourists

1. To eliminate the tourists do the same, but this time by successive keys, with a soft brush on board (Circle Fuzzy) and average opacity so that your patches are not too visible. Vary source constantly taking care to respect the line of the waves and the different shades of the sea Stop the body parts in front of the boat.
   
2. To create the right side of the boat hidden by tourists, you'll choose the Selection tool to select hands and the left side of the boat to the center, roughly. Then go to the Edit menu, click Copy first, then Paste. The selection appears in a rectangle surrounded by yellow dots. Reverse the tool with the Flip, and then with the Move tool, position it so as to reconstitute a full boat. Click outside the selection rectangle to select and merge the image.
   
   Repeat the cloning tool and polish your trick by removing body parts and erasing the remaining solder in the middle of the boat.

Reduce noise and improve sharpness

The noise is most evident when you take pictures with high ISO sensitivity. It is a phenomenon of the digital noise which produces a particularly troublesome granulation in the flat and gray areas. The noise is more noticeable if you print your images in large format. To avoid noise, no miracle! It must be limited to low sensitivity and use a tripod or the flash when the light really miss.

Today, most digital cameras allow you to climb to 400 or even ISO 800 without too much damage. Make your own tests and set your own limits not to cross. Gimp offers a few tools to fight against noise, but are not really satisfactory. That is why we will use a dedicated software.

Step 1: Fix the noise

1. Download Neat Image demo. Install the program and open it and click Open Input Image.
   
   Select the image to be processed. Go to the Device Noise Profile tab. Using the mouse, draw a rectangle in the image into a flat area where noise is important, this sample will serve as the basis for the correction. Click Auto Profile. You can also let the software choose just by clicking on Auto Profile.
   
2. Switch to next tab, Noise Filter Setting, and click Preview. An overview of the effect appears in a square. Zoom to 100% and move the square to judge the quality of treatment.
   
   If the result does not suit you, change the settings with the sliders on the right. They define the amount of noise and intensity of the correction depending on the type of noise: luminance noise (small bright or dark) and chroma noise (colored spots).
   
   Then go to the Output Image tab and click Apply to apply the change to the whole image and then click Save to save output image. Click OK to dismiss a window and save your image to be known from the original version with the suffix filtered. The demo version of the software lets just save in Jpeg, without choosing the compression level.

Step 2: Unsharp Mask

The last step is to improve the sharpness. We carry out this operation by returning to The Gimp in the Filter menu, Improvement and Unsharp Mask. Expand the dialogue box by catching a corner to get a better overview of the report and move the three sliders until the desired sharpness. This filter works by building micro-contrasts and outline of objects. The first slider defines the range, the second, the degree of the effect and helps to preserve the flat areas. Use in moderation so as not to reveal halos around objects or highlight defects, such as digital noise.

Hello,

I just downloaded GIMP to edit my pictures with and I have a slight but excruciating problem - at the top left corner of my picture (as shown in the editing window) is a scaled down version of it that would not go away even after I have finished editing and saved it. To my annoyance the little miniature version is still there upon normal viewing of the images.

Subsequently, every picture I open in GIMP has the same issue.

How can I solve this problem?

Thanks for your help.

Have you tried the last step i.e Unsharp Mask on your pictures? There is a filter called Unsharp Mask, which can be found on the GIMP image toolbar at Filters » Enhance » Unsharp Mask. The Unsharp Mask filter sharpens edges of the elements without increasing noise or blemish. It is the king of the sharpen filters.

If this post is still active.... I was looking at the GIMP software, and was not sure what version I should download for my Windows XP computer. I clicked on windows download, and it opened an FTP page that had over 100 files... My old brain became quickly confused.

Wonder if I could get a little help from an expert?

You can make use of any version of the GIMP application. Gimp software is compatible with Windows Xp very well. Let it be any version of the same that you download you will not face any problem regarding its functionality or installation. So check out for the same on its official site. I hope the application will be able to get installed well and can then process as you required. Do check out.