![]() ![]() The background areas turn dark blue, and your rough selection area turns light blue (see below). All you want to do is define the area that GIMP will be processing and then press the Enter key. The first step is to roughly outline your subject – with an emphasis on the word roughly. This tool has a few stages, but they’re fairly simple – and GIMP puts tooltips at the info panel along the bottom of the editing window to give you a bit of prompting. Start by choosing the Foreground Select tool from the toolbox. It’s an interesting combination of precision and generality, and it’s a bit hard to use at first, but with practice, it starts to feel like second nature. If the Fuzzy Select tool didn’t get everything perfect, you might have better luck using the Foreground Select tool. If it won’t work properly, you might still get a good starting selection that can be refined with the other methods. Try experimenting with different threshold options and different initial click locations. Since it’s so fast, it’s often worth giving it a try just to see if the results are usable. The only real control you have over the final selection comes from adjusting the Threshold setting in the tool options, which determines the size of the color selection range. Well, for the most part, it’s very helpful when used on the right image – but it can also run into trouble fairly easily. Setting the Threshold level too low can leave out unnoticed background colors and require some additional help to create a good selection, as you can see in the bottom left of the image and along the green leaf edges This is GIMP’s name for a “magic wand” type of selection tool that automatically selects all pixels within a specific color range of the first color your click on. The fastest way to create a selection around your subject is to use the Fuzzy Select Tool. Holding down the Shift key adds to your existing selection, while the Ctrl key subtracts. You can also combine them to get the results you need without doing everything by hand. Selecting single strands of hair may come to haunt your dreams.įortunately, there are some helpful tools that can make the process simpler and far less stress-inducing. It’s simple enough if you’re working on a photo of a plain plastic cube, but as soon as your shapes get more complex, the time investment grows rapidly. This part of the process is by far the most time-consuming and fiddly. Step 2: Isolate Your Subject With A Selection If the option is unavailable, your image probably already has an alpha channel.Īlpha channels are created automatically once you add multiple layers to an image because transparency is an essential element of how the layer compositing works, so that may have taken care of things for you already. The simplest way is to open the Layers menu from the menubar, select the Transparency submenu, and click Add Alpha Channel. There are two ways to add an alpha channel to your image. Alpha channels are also just grayscale images, but instead of representing red, green, or blue, any white pixels it contains are treated as transparent. In order to add transparency to our image, we need to make sure it contains a fourth channel called an alpha channel. Each channel is just a grayscale image, but depending on which channel it represents, white pixels display as the channel color and are combined to make a normal image. Typical computer images are made up of three color channels: a Red channel, a Green channel, and a Blue channel. Step 1: Adding Transparency with an Alpha Channel Step 4: Export Your Image as a PNG File.Step 3: Remove or Hide Unwanted Background Areas.Step 2: Isolate Your Subject With A Selection.Step 1: Adding Transparency with an Alpha Channel.However, one can also use the eyedropper tool to pick a colour from anywhere on the desktop. Here, I used f3f3e9 as a background colour for plain colour filling. Click on the background colour rectangle in the upper half of the Tool Options toolbox window to change the background colour. (In this respect, Adobe Photoshop is no different.) Hence, choose a colour which is compatible with the background on which the resulting picture will eventually be used. Some colour mixing will be inevitable and even desired. Do select BG colour fill and Sample merged and run a few tries while adjusting Threshold for best results. Within the Bucket Fill toolbox options, select Fill transparent areas only when necessary. Select the bucket fill tool or hit Shift+ B. The next step is optional and consists in filling the area that should become transparent with a plain colour first. This is done by selecting Layer → Tranparency → Add Alpha Channel. If this is the case, add an alpha transparency channel. Some image types lack a transparency channel JPG for example. La trahison des images by fellow countryman René Magritte partly vandalised for the purpose of this tutorial. ![]()
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