2.0 4 Easy Ways to Delete Background to Transparent with GIMP. 2.1 Using GIMP to Delete Background to Transparent

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1 1.0 Introduction As JPG files don't support transparency, when you open a JPG image in GIMP with the purpose of making the background transparent. The first thing you must to do is Add Alpha Channel. It is quite simple. Just right-click on the layer you're trying to make transparent and select Add Alpha Channel. Note: An alpha channel is essentially a transparent layer that gets positioned beneath your image Easy Ways to Delete Background to Transparent with GIMP In today's tutorial I'll be demonstrating how you can use GIMP to delete an image's background to transparent while leaving the subject in place. There's a variety of ways to accomplish this with GIMP, but I'll be covering the main methods that are easiest to apply as a beginner. The method you should use depends on the type of image you're working with and how comfortable you are using GIMP to delete backgrounds to transparent. 2.1 Using GIMP to Delete Background to Transparent The first step is to create a selection from either the subject or the background. Whatever is easiest is what you should choose. 2.2 Method 1: Fuzzy Select Tool According to GIMP's documentation, the Fuzzy Select Tool allows you to select areas of an image based on color similarity. This method works great if your image's background has a different array of colors than the subject you'd like to crop out. From the left-side Toolbox, activate the Fuzzy Select Tool. With the tool selected, click and drag on your subject to create a selection. You can add to your selection by holding Shift and clicking on another area, and you can remove unwanted selections by holding Control and clicking on them. This will create a dotted outline around your subject known as a selection. If you created the selection by clicking on the background, simply press Delete on your keyboard and you will have successfully used GIMP to delete your image's background to transparent. Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 1

2 If you created the selection by clicking on your subject, you'll only have your subject selected. Since you want to delete the background and not the subject, simply go to Select > Invert. Nothing will change visibly on the screen when you do this, but what happened is you inverted the selection so that you now have the background selected and not the foreground. Once you've done that, simply press Delete. Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 2

3 2.3 Method 2: Select By Color Tool An even simpler method - similar to the Fuzzy Select Tool - is the Select by Color Tool. Once you click on a specific pixel with this tool, it will create a selection around it and every other pixel with the same color. This tool works great if you have an image where your background consists of just a single color and maybe a few different shades of it. From the left-side Toolbox, activate the Select by Color Tool. With the tool selected, simply click on a segment of the image that contains the color you'd like to delete. You can increase the size of the selection by clicking and dragging to the right, or decrease it by clicking and dragging to the left. You can also select additional shades of the same color by holding Shift and clicking on them as well. Once you'd created a selection from your background, press Delete on your keyboard. If it's easier for you to create a selection from your foreground/subject instead, go ahead and do so, then just go to Select > Invert before deleting the selection. Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 3

4 2.4 Method 3: Paths Tool This is the method that requires the most skill and takes the most time, but it's also the best method of using GIMP to delete background to transparent in my opinion because it produces the cleanest, most professional result. This is the method that was used to crop the orange image in this picture - the Paths tool. The Paths tool allows you to create a selection by manually placing smooth lines and curves via node placement. This is the ideal method to use if there is simply not enough contrast between your image's subject and background for the previous methods to work. 2.5 Method 4: Layer Masks The final method I'll be outlining isn't necessarily a tool, but rather a series of functions. The idea behind this method is to strip down your image to black and white, then adjust the color curves to create some separation between the foreground and the background. Once that's done, we'll use layer masks to define the transparent areas. This method is ideal for cropping out subjects with fine details like fur or strands of hair. However, it's the most complicated method of the 4 thus I'll use an example to Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 4

5 show in details how it's works. 2.6 Masking Hair with Fine Details There are many ways of masking objects with GIMP. This tutorial shows a way that produces good results for fine details like strands of hair, especially for portrait photos with a simple background. 1. Open up your image in GIMP. Click on duplicate layer and duplicate the background. 2. The next step is important: In order to prepare for the layer mask, we need to convert the duplicate layer to grayscale as the first step. The best way to do so is using the Desaturate command (Colors menu > Desaturate) and I'm using the "Luminosity" option here. Press the OK button after making your selection. 3. The next step is to adjust the gray tones so as to increase the contrast that will help you separate the hair from the background. Do this by clicking on Colors menu > Curves. Adjust the curve similar to the figure as shown below. Hopefully, the hair strands will become darker with all its fine details be kept and the background lighter. It doesn't matter if the model's face looks strange (like on the screenshot). Only the HAIR matters. Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 5

6 4. Now, we want the background of our layer mask to become black and the model become white. This is in opposite to the current situation of the image. Thus we need to invert it. Do this by clicking on Colors menu > Invert. 5. Now we paint the parts that don't need masking with white (the skin and the hair where's no background). - Select the Paintbrush tool - Use a big brush size (relatively hard with some soft edge) - Choose foreground color: white - Make the parts white Start painting the regions that don't contain details relevant for masking. You can paint them roughly/quickly. 6. Now we adjust the gray tones of the picture. For this it is important to make the background completely black while the hair should become (nearly) white. In the next step everything that is white will become visible and black regions will become transparent. Now my image looks like this: Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 6

7 7. Now we have to create a layer mask and copy the details from the grayscale layer to this mask. - Edit / Cut (or hit Ctrl + X) - activate background layer - Right-click into the layers dialog: Add layer mask (White) - Click on the small white area next to the background layer in the layer dialog to ensure that you're working on the mask and not on the picture itself. - Edit / Paste (or Ctrl + V) Important: After that, the pasted layer is a floating selection. To fix it on the layer, use the "Anchor" button of the layer dialog. Your layers dialog should now look like this: 8. At the end, we want to insert a new background and do some final adjustments. Choose File > Open as Layers and select the "background sunset.jpg". Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 7

8 It should be an own layer in the image now. In the layers dialog, move the sunset layer to the bottom. Compiled by K.T. NG Sept. 2018, Rev 1.0 Page 8