Gimp is arguably the closest free alternative to Photoshop. Unlike other free programs we have already told you about, such as Darktable or Rawtherapee, Gimp allows us to work with layers and offers us a large number of tools to process and modify our photographs in a very precise way.
All of this makes it a very interesting free software program for both beginners and experienced photographers, which is why today we want to introduce you to this wonderful image editing program.
Download and install Gimp
The first thing, of course, will be to download and install Gimp free Italian download. As I said before, Gimp is a free software program, which means we can download it for free from these links.
Gimp Download ITA
Above you can download the program installation file. It is available for Windows, Mac and Linux.
After downloading the installation file, simply double-click it and follow the steps indicated by the installer. You can choose the language and directory in which to install the program. The good thing about Gimp is that it is available entirely for many countries, something very positive if English is not your thing.
Gimp main interface
Now that we have installed the program, we will analyze its main interface, to learn about its most important tools and menus. As soon as we open the program, the following window will appear, with various menus and option panels:
- The best menu
- Open the file tabs
- File display window
- Instrument panel
- Brushes, patterns and fonts panel
- Layers, channels and paths window
We will look at each of the menus and panels separately to find out what each of them contains and then get to know the program in depth.
In the top bar of Gimp we find various menus. Knowing them will be essential to use many of the program’s tools and options:
- File: In this menu you can create, open or save any image file. It also allows you to scan photos and print them, as long as you have the appropriate devices connected to your computer, of course.
- Edit: from this menu it is possible to undo and redo the last actions performed and view their history. You’ll also find options to fill a layer or selection with colors or patterns or paint an outline following a selection. Finally you will find the program configuration options, such as preferences or custom keyboard shortcuts.
- Select: Here you will find all the options for making and editing selections. It allows you to select everything, delete a selection, invert it, blur its edges or refocus it or change its shape and size. From here you can also create a selection by color if you prefer. Finally, you can also convert it to a layer mask or save it in the Channels window.
- View: from this menu you can adjust all the program viewing options. You can also enable and disable guide and measurement tools, such as guides or the grid.
- Image: From this menu you can perform many actions that will affect the whole image, regardless of the layers it has. You can duplicate it, rotate it, flip it, resize it or crop its canvas over content or an active selection. You can also choose the color mode and depth and how it is handled in the program. On the other hand, from here you can also combine the file’s layers, flatten them all, and even align them based on their content.
- Layer: This menu is similar to the previous one, but instead of affecting the whole image, we will only affect the selected layer or layers. From here you can create a new layer or create a group with the selected layers, duplicate it, anchor it, delete it, reduce its transparency, resize it, rotate it or crop it. You can also add a layer mask, either blank or taking into account an active selection.
- Colors: in this menu you will find all the adjustments needed to retouch the luminance and color of your photographs, such as color temperature, exposure, contrast or saturation. You can also act directly on the photo’s histogram from the Levels and Curves settings. In this menu you will also find the automations of some adjustments and some color effects, such as Posterize, which reduces the amount of tones in the photo.
- Tools: Although the most used and important are shown in the tools panel, in the Tools menu you can find all the tools available in Gimp, to select from here.
- Filters: in this menu you will find a large number of filters to modify your image. You can apply blur, sharpen and distortion effects, create lighting effects, add noise, apply painterly and artistic effects, and more.
- Windows: from this menu you can show or hide the different panels and windows of Gimp, as well as manage the various open files.
- Help: as the name suggests, in this menu we will find all the Gimp Help options, from tips and tutorials to information on the installed version and program updates.
2. Open the File tabs
Above your image you will find one or more tabs, depending on how many files you have open. You can switch between them simply by clicking on these tabs. If you want to close one, press the X that appears next to the photo thumbnail when you have that file visible.
3. File display window
The whole big part of the Gimp interface is the image viewing window. It is surrounded by millimeter rulers that will mark the dimensions of our photograph in pixels. If you click on one of them and drag and hold the mouse button, you can draw a guideline, both horizontal and vertical. These guidelines are only visible in the program, your photography will not be altered by them.
If you prefer these rulers to show other units of measurement, you can find an extensive list in the PX drop-down menu that you will find at the bottom left of this window.
Next to this drop-down menu you will find another one with the zoom percentage of the image. You can choose another percentage to zoom in or out of the photo, or write the percentage you prefer by hand. You can also zoom in or out by pressing the + and – keys on the numeric keypad or pressing Control while moving the mouse wheel in (zoom in) or out (zoom out).
4. Instrument panel
The instrument panel on the left side is divided into 4 parts:
- At the top we find all the icons of the tools available.
- In the center we find the Color Picker, useful only for tools that work with color. Here we can select the foreground color and background color, with multiple tools or numerically.
- Below the color picker we find the tool options panel, which will change depending on the tool we select. Here we can configure this tool to our liking.
- Finally, at the bottom we find the buttons for the Default Settings of the instruments, where we can save and load specific configurations of each instrument.
We can find many very useful tools for working with our photographs. We will describe them in order of appearance:
- Rectangle Selection Tool (R): With this tool you can create a rectangle-shaped selection. Click and drag the mouse to create the rectangle to your liking. If you want to modify it, once created you can stretch any of its corners or sides to resize it. If you press Alt and drag you can move the selection wherever you want.
- As with all selections in Gimp, pressing Shift while creating the selection will add that new selection to the active selection, and pressing Control will subtract the new selection from the active selection.
- Elliptical Marquee Tool (E): This Marquee Tool works the same way as the previous tool, but instead of creating a rectangular-shaped selection it will create an elliptical-shaped selection.
- Free Selection Tool (F): This tool will allow us to create selections with custom shapes. If you hold down the mouse button and drag you will create the freehand selection. On the other hand, if you click, you will create the selection in a polygon shape. When you want to close the selection, go to the beginning of it and a circle will appear that you need to tap to finish it. Once created, you can tap any of the edges of the selection to change it to your liking.
- Diffuse Selection (U): With this tool you can select all contiguous pixels of similar tone with a single click. In the tool options window you will find a slider to change the selection threshold. The wider the threshold, the more tones the selection will cover.
- As with other selections, if you want to select multiple tones you need to click again with the Shift key held down, and if you want to subtract tones from the selection, you need to click while holding the Control key.
- Select by Color Tool (Shift + O): With this tool you will be able to select all the pixels of the photograph that are of the same color. As with the fuzzy selection, in the tool options window you will find a slider to adjust the selection threshold.
- Selection Scissors Tool (I): This tool can automatically analyze and select a well-contrasted outline. So, you just have to click along this outline without having to be too precise, as the scissors will be precise for you. When finished closing this outline, press Enter to create the selection.
- As with all other selections, pressing Enter while holding down the Shift key will add the new selection to the active selection and holding the Control key will subtract it.
- Foreground Selection Tool: This tool is used to create precise selections in an easy way.
- First, create an outline around the element you want to select; works like the free selection tool. When you have closed the outline of this selection, press Enter to create it. You will see the whole image turn navy blue showing the mask for this selection.
- Now the cursor will have turned into a brush, which you can configure in the tool options panel. Paint inside the element you want to select, trying to paint over all its different shades, so that they are all selected.
- When you press Enter again, the layer mask will update and become much more accurate than before. You can paint again if any shades have been excluded from the selection.
- Finally, hit Enter again so that this mask is permanently turned into a selection.
- Path Tool (B): This tool is the equivalent of Photoshop’s Pen Tool and works in a similar way. If you click, you’ll create a polygonal path, just like with the free selection tool. However, the beauty of this tool is that if you click and, without releasing the mouse button, drag, this straight line will turn into a curve. Curves can be created for very precise and dynamic selections. Each stitch you create will have two handles that determine how the next curve continues; Move them by pressing the Control key to draw the curves as you wish. When you close this path, pressing Enter will create a selection.
- You can do many other things with this path, such as outlining it or filling it with color. To access the menu where you can choose all the options for the newly created path, go to the layers window and click on the Paths tab. Clicking with the right mouse button on the thumbnail of the route that appears in this window, a menu with all the options will be displayed.
- Tool of the selection color (O): This tool is used to copy any of the colors of our image in the color picker, so paint with that exact tone. Just click on the pixel of the color you want to copy and it will be added to the foreground color of the color picker. If you click while holding the Control key, instead of adding it to the foreground color, it will be added to the background color.
- Magnification Tool (Z): With this tool you can enlarge your image to work better if you need more precision. Clicking on an area of the image will zoom in and pressing Control + click will zoom out. As I said before, you can also zoom in or out by pressing the + and – keys on the numeric keypad, or by pressing Control while moving the mouse wheel forward (zoom in) or out (zoom out).
- Measure Tool (Shift + M): With this tool you will be able to know exactly how much a specific distance measures in your image. Simply click, drag and release the mouse button just at the end of the area you want to measure to create a measurement line. Below the image you will see both the pixel size of this line and the exact angle it has. If you press the Control key while creating, the angle will not be free but will jump from 15º to 15º.
- You can change the unit of measurement of this tool from the drop-down menu that you will find below the image.
- Move Tool (M): With this tool you can move a layer, selection or path as you wish.
- Alignment Tool (Q): With this tool you can align or center the various layers of your file. Click and drag to draw a square on the layer you want to align, to select it. If you press Shift while creating the square, you can select more than one layer, in case you need to align a group of layers at the same time. In the tool options window you will find various ways to align the layers.
- Crop Tool (Shift + C): This tool is used to crop the photo and reframe it. Click and drag to create a rectangle that will determine the new framing of the photo. Once created, you can pull its corners and edges to adjust it. After adjusting the crop, press Enter to crop. In the tool options window you can configure a fixed proportion of this frame, so that the crop has a specific format if you prefer.
- Another very interesting option that we find in this tool is the box “Only the current layer”. If we mark it, instead of cropping the entire photograph, we will only be cutting the layer we selected.
- Unified Transform Tool (Shift + T): This tool is similar to Photoshop’s Free Transform. With this tool you can freely move, resize, rotate and / or distort your layer, selection or path. When you’re done editing it, press Enter to accept the transformation.
- If you press the Control key while resizing, the resizing will be done from the center of the layer. If, on the other hand, you press the Shift key, you can break the aspect ratio of the image to deform it.
- If you hold down the Shift key while rotating, instead of rotating freely, you will jump 15º.
- If you press the Control key while distorting it, you’ll keep perspective. If you press the Shift key instead, you will constrain the distortion to certain specific angles.
- Rotation Tool (Shift + R): with this tool you can rotate, either by eye or numerically, any layer, selection or path.
- Tool (Shift + S): with this tool you can resize, either by eye or numerically, any layer, selection or path.
- Skew Tool (Shift + H): with this tool you can skew, either by eye or numerically, any layer, selection or path.
- Handle Transformation Tool (Shift + L): with this tool you can deform the layer, selection or path, creating anchor points on it by simply clicking wherever you want. Then, by clicking and dragging on these points, you can deform the layer, selection or path according to them.
- You can move any of the points created by clicking on it while holding the Shift key and delete it by clicking on it while holding the Control key.
- Perspective Tool (Shift + P): With this tool you can change the perspective, both by eye and numerically, of any layer, selection or path.
- Rotation Tool (Shift + F) : With this tool you can rotate both horizontally and vertically, any layer or path selection.
- Transform Grid (Shift + G): With this tool you can dimension an area by clicking to create and close it, as we did with the free selection tool. Once this area is closed, it will become a transformation grid. You can distort this grid to your liking by moving its handles. When you press Enter, the layer will warp to conform to the new grid.
- Warp Transform (W): This tool is similar to the Liquify tool in Photoshop. It will allow us to warp our photography by “pushing” the pixels. We have a cursor that can be enlarged or reduced from the tool options window and pressing and dragging this cursor will move the pixels that enter its circle. From the tool options window we can also configure the hardness and strength of this shift. This tool can be ideal for modifying the silhouette and shape of our models’ clothes or hair.
- Text Tool (T): This tool will create a text box on a separate layer. In the tool configuration window you can change its font, color, size, alignment, etc. You can easily see all the available fonts from the Fonts tab, in the right window.
- Fill Tool (Shift + B): This tool fills all contiguous pixels of a similar hue with a color or pattern. In the tool options panel you can configure it to fill the entire area bounded by an active selection instead.
- Gradient Tool (G): This tool will create a gradient between two or more colors, or from one color to transparent, to make it blend. You can configure both the colors and their shape in the tool options window. To create the gradient, simply click where you want the first color to start, drag and drop where you want the last color to end.
- Pencil Tool (N): This tool will allow us to paint with the main color from the color picker. In the tool options panel you can configure aspects such as the size, hardness or angle of the pencil. You can also choose its shape and other preset effects in the brush window on the right.
- If you paint over one point and (without painting) go to another point and paint while holding the Shift key, a completely straight line will be created from point to point. It will work with any tool that uses brushes.
- Brush Tool (P): The Brush tool is very similar to the Pencil tool, but its edges will be more diffuse.
- Eraser tool (Shift + E): this tool is also very similar to the brush tool, only instead of painting it erases. The eraser will eliminate the areas where we paint, leaving that part of the layer transparent or painting it with the background color of the color picker.
- Airbrush Tool (A): This tool is similar to the brush, but its flow will be less. With the airbrush we will have to give different passes through the same site if we want it to be completely covered.
- Ink Tool (K): This tool is similar to the pencil but gives us extra help to simulate a fountain pen. The longer we hold the mouse down on the same site, or the slower we draw the lines, the thicker they will be; and vice versa, the faster we are, the thinner the lines we draw. This effect is ideal for simulating calligraphic writing.
- MyPaint Brush Tool (Y): MyPaint is a free program with a multitude of very useful brushes, and thanks to this tool they can also be used in Gimp.
- Cloning tool (C): this tool will allow us to clone one area of the photograph onto another. Press Control + Click on the area you want to clone and paint over the area you want to cover. The brush of this tool can be configured as a normal brush from the tool options window, and we can also choose other brushes other than the brushes window, which will allow us to create textures and effects.
- Healing tool (H): This tool works the same way as the cloning tool. However, just as the cloning tool copies one area to another, with the sanitizing tool Gimp will recalculate the covered area to preserve its tones and better integrate the cloned area. This tool is ideal for removing small pimples and spots on the skin.
- Clone Perspective Tool: This tool works like the Clone tool, but will clone the area after applying a perspective transformation, so that the copy conforms to the transformed perspective.
- Focus and Blur Tool (Shift + U): This tool will blur the area you paint or bring it into focus if you hold down the Control key while you paint. The brush of this tool works like any other brush and we can configure it from the tool options panel. As with other brushes, we can also choose other brushes with various shapes and effects from the brush window on the right.
- Smudge Tool (S): This tool will blend the area where we paint, mixing the colors of the pixels in that area. The more we insist on an area, the more the pixels will merge and the more it will blur. As with the other brushes, we can configure it from the tool options panel and we can also choose other brushes with different shapes and effects from the brushes window on the right.
- Burn / Markup Tool (Shift + D): with this tool we can overexpose (lighten) an area if we paint over it, or underexpose (darken it) if we paint while holding down the Control key. As with the other brushes, we can configure it from the tool options panel and we can also choose other brushes with different shapes and effects from the brushes window on the right. With this tool we can create the famous Dodge and Burn effect.
5. Brushes, Patterns and Fonts panel
On the right side of the interface you will find a panel with 3 tabs: Brushes, Patterns and Fonts. From these 3 tabs we can configure many of the tools we have just seen.
- From the Brushes tab we can choose brushes with different shapes, hardnesses and effects to use them not only in the Pencil and Brush tools, but in any tool that uses brushes, such as the cloning, sanitizing, blurring, smudging, burning tools, etc.
- From the Patterns tab we can choose patterns with different textures to configure the tools that use patterns. Remember that you can configure most of the tools that use brushes, in the tool configuration dialog, so that instead of painting with solid colors they use patterns.
- From the Fonts tab we can choose the different fonts that we can use with the Text tool.
6. Levels, channels and paths window
Finally we find the window of levels, channels and paths. In these 3 tabs we will see all the layers of the file, the image channels and the routes that we have created with the tools we have seen before. On these thumbnails we can press the right mouse button to view all the options that concern them.
As a general rule, the tab we will use the most is the Levels window, so by default this is the one that will always appear visible. In this window, you can drag layers on top of each other. It works like the typical onion paper used for tracing: the layers above will be seen first and the others will be behind. From the opacity slider we can make the layers transparent to show the underlying ones too.
Above the opacity slider we will also find the Modes drop-down menu, with all of Gimp’s layer blending modes. These modes will cause the upper layer to blend with the underlying ones in different ways, so that it integrates better.
Finally under the whole we find a small toolbar where we can:
- Create a new layer: it will create a new layer with a transparent background or filled with a color or pattern that we choose in the configuration window.
- Create a group of layers: it will create a folder in which we can drag various layers inside. These layers will form a group, with which we can move them all at once and apply effects to them all at once, such as varying the opacity, changing the mode or adding the same layer mask to all of them.
- Level up or down by a level: with these arrows you can place a selected level in front of or behind other levels. You can also do this by simply clicking with the mouse and dragging the layer to the position you prefer.
- Duplicate a layer: this button duplicates the selected layer.
- Anchoring the floating layer: When we create a selection, a layer called a floating layer (or floating selection) is created in the layers window. As long as it is active we can only work on it. However, if we want to work on the rest of the image without losing this selection, we can use this button Dock the floating layer and undock it when we want to continue working on the selection.
- Add a layer mask: we can add a layer mask to the selected layer with this button. A second thumbnail will be added to the right of the layer, where we can paint in grayscale. White will show that area of the layer and black will make that part of the layer hidden and transparent. The whole range of gray in between will make the transparency of the layer higher or lower. You can paint on the layer mask with any brush, so its characteristics (such as shape or hardness) will affect the visibility of the layer. You can also paint a gradient from white to black to gradually blend the layer.
- You can see the larger mask to work better with it by pressing Alt + clicking its thumbnail in the layers window. Press ALT + click on it again to show your photo again instead of the mask.
- You can hide the mask by pressing Control + click on it. A red square will appear around it indicating that it is inactive. Press Control + Click it again to activate it again.
- If you add a layer mask while you have an active selection, the mask can take the shape of the selection. When creating the mask, choose the “Selection” option from the menu.
- Delete a layer: with this button you can delete the selected layer.
This little options bar also changes when we change the tab to the Channels or Paths tab:
- In the Channels tab we will find the options to create new channels, raise and lower the level of the selected channel, duplicate a channel, transform the channel into a selection or delete a channel.
- In the Routes tab we will find options to create a new route, level up on a selected route, duplicate a route, convert the route to a selection, convert a selection to a route or paint along the route.
Now that you know Gimp’s entire interface and main tools, it’s time to experiment with them all to master the program. I am aware that it can be overwhelming to know so many options at once, so it is best that for now you focus on managing the ones that are most useful to you and gradually practice with them and learn.