Ceci est une ancienne révision du document !
In the first of this new GIMP series, I’m going to try and show you some intermediate techniques. In other words, things that people may think are possible only with Photoshop. If you’d like to read more about the absolute basics of GIMP, then I refer you back to FCM#12-19. While I used an older version of GIMP in those issues, the layout of GIMP has changed little in the passing years. For ideas, I’m using Photoshop tutorials that are freely available on the web, and, while not copying them step for step, applying the underlying principles of them to GIMP. I should also state, for the record, that I’m using GIMP 2.6. As I write this, a 2.7 version is available, but, it is not entirely compatible with the *buntu family, and trying to install it can give conflicts. What we’ll be making is shown left.
Dans ce premier numéro de cette nouvelle série sur GIMP, je vais essayer et vous montrer des techniques intermédiaires. En d'autres mots, des choses que les gens pensent ne pouvoir faire qu'avec Photoshop.
Sources: Sky - http://www.2textured.com/index.php/Environment/Skies/skies_0347 YouTube Video showing Pt1 being made: http://www.youtube.com/watch?v=NYFTdbzjubg The Sky Gradient First thing we need to do is create a new image (File > New), and make it A4 in size, portrait in orientation, and with an X and Y resolution of 80. The default X and Y resolution is 300. That’s for professional printing, and, it requires high resolution images as source material, and can slow down even the hardiest of machines - so we’ll go with 80 which is more than adequate for this tutorial. Select the ‘Blend tool’ icon (shown left), and, where it says ‘Shape:’, choose ‘Radial’ from the drop down menu. No need to change anything else for now. For a foreground color, choose a very pale greeny-yellow (RGB = 220, 229, 189). For the background, choose a slightly faded greeny-yellow (RGB = 133, 151, 81). Next, left click (and hold) in the middle of the blank image and move up to the top middle of the image. Release the mouse button and you’ll have a radial fill covering the entire canvas. No, Not The Layers! Click File>Open, and choose your sky image. To quickly get the sky into our main image, we go to the ‘Layers’ tab and (as shown above) drag it onto our main image With the sky now in our main image, you can close the opened sky image. The sky image is quite high resolution, larger than we require, so we need to resize it. Click the ‘Resize’ tool (shown left), and click the sky. In the resize window that pops up, you need to make sure that the little chain link icon is linked. If the icon looks like a broken chain, then your sky image will resize disproportionately and squish. Make the width of the sky about 300 wide, and click OK. This gives us some room to play with. Click the ‘Move’ icon (shown left). Now, left click and drag the sky icon to where you think it looks best. TIP: The gradient is one layer and the sky is another. If we add several more layers, it’ll get quite confusing. To make things easier you can double click on a layer name and rename it. Now for some layer magic. With the sky layer still selected, click the drop down menu above the layers and choose ‘Value’. Color Curve You’ll now have a greeny sky, but it doesn’t look very dramatic does it? With the sky layer still selected, click Colors > Curves from the menu. We’re going to create what’s known as an S-curve. The S-curve is a great way of quickly color correcting your photos too. Click two boxes across and two down in the grid, and drag your mouse up and to the left slightly, and two boxes in and up from the bottom left of the grid, and click and drag down to the right. Which will give you an S-curve (shown above) which you should play around with until you get a nice dramatic sky with good darks, but not too bright lights. Let’s finish off this sky and that’ll do us for this first part of the tutorial. Layer Mask Right click on the sky layer, and from the menu, choose ‘Add Layer Mask’ (shown below). From the window that pops up, choose ‘White (full opacity)’ and click ‘Add’. You’ll see a box appear next to your sky thumbnail in the list of layers. That box is a thumbnail of the layer mask. The idea is that if you select that layer thumbnail, and draw in black, you’ll erase parts of the sky image. Draw over the erased area with white and the sky will reappear. This means you can show/hide parts of the sky - using the mask - without destroying the original sky image. We’ll use the mask to fade the sky into the background. Make sure the mask thumbnail is selected, it should have a white outline, and click the “Rectangle Select’ icon (shown below left). Left click and draw a box around the bottom third of the sky. Now click the ‘Blend Tool’ icon (that we used at the start of this tutorial), but make sure the ‘Shape:’ is Linear this time. You’ll need a foreground colour of black, and a background colour of white. With that all set, click and drag just up from the bottom middle of the selected area, to just below the top middle of the selected area, and release the mouse button. Your sky will now magically fade into the background. And since it’s a layer mask, the original sky is untouched. You can right click on the layer mask and delete it and the sky will return to its original state. Next month we’ll add a piece of landscape below the sky, and maybe, just maybe, start growing that beanstalk. Class dismissed!