1. Layers
1. Concept
◦ Layers are like transparent sheets of paper. You can draw or place different elements on each sheet of paper, and then stack these sheets of paper to form the final image. For example, when making a poster, you can put the background image on the bottom layer, the text on the top layer, and the decorative elements on the upper layer, so that you can easily operate each element separately without interfering with each other.
2. Operation
◦ Create a new layer: In most image processing software, there is a button for creating a new layer. For example, in Photoshop, you can create a new blank layer by clicking the "New Layer" option in the "Layer" menu or using the shortcut keys (Ctrl + Shift + N/Command + Shift + N).
◦ Adjust the order of layers: Changing the stacking order of layers can change the display effect of the image. For example, if you move a layer containing text below the background layer, the text will be covered by the background. You can adjust the order by directly dragging the layer in the layer panel.
◦ Adjust the transparency of the layer: By changing the transparency of the layer, you can make the elements in the layer appear semi-transparent. This is very useful when making fusion effects or watermarks. In the Layers panel, there is an Opacity slider that you can drag to adjust the transparency of the layer, ranging from 0% (completely transparent) to 100% (completely opaque).
2. Selection Tools
3. Rectangular Marquee Tool and Elliptical Marquee Tool
◦ Function: Used to select rectangular or elliptical areas. For example, if you want to crop a part of an image or copy a circular area in an image, you can use these tools.
◦ Operation: After selecting the tool, drag the mouse on the image to create a selection. Press and hold the Shift key to create a square or circular selection. After the selection is created, you can copy, move, delete, and other operations on the content in the selection.
4. Lasso Tool
◦ Function: There are three types, namely the Free Lasso Tool, the Polygonal Lasso Tool, and the Magnetic Lasso Tool. The Free Lasso Tool allows you to select image areas just like freely drawing a selection on paper with a pencil; the Polygonal Lasso Tool is suitable for selecting areas with straight edges, such as polygonal objects; the Magnetic Lasso Tool automatically absorbs edges with obvious color contrast in the image, making it easy to select objects with complex shapes.
◦ Operation: For example, when using the Magnetic Lasso Tool to select an object with complex edges, you only need to click near the edge of the object, then move the mouse along the edge, the tool will automatically absorb the edge, and finally return to the starting point to close the selection.
5. Magic Wand Tool
◦ Function: Used to select areas with similar colors. It will determine the selection range based on the tolerance value (Tolerance) you set. The higher the tolerance value, the wider the color range of the selection.
◦ Operation: For example, if you have an image with a relatively single background color and want to remove the background, you can use the Magic Wand Tool. After selecting the tool, click in the background area, and then adjust the tolerance value according to the actual situation until a satisfactory background area is selected, and then press the Delete key to delete the background.
3. Image Adjustments
6. Brightness/Contrast
◦Function: Brightness adjustment can make the image brighter or darker as a whole. Contrast adjustment increases or decreases the difference between the bright and dark parts of the image. For example, an underexposed photo looks darker, which can be improved by increasing the brightness; if the photo looks gray, increasing the contrast can make the image more layered.
◦Operation: In software such as Photoshop, you can open the adjustment dialog box through the "Image" - "Adjustments" - "Brightness/Contrast" menu. Drag the brightness and contrast sliders to achieve the desired effect, and you can observe the real-time changes of the image.
7. Hue/Saturation/Lightness (HSL)
◦Function: Hue refers to the type of color, such as red, green, etc.; saturation is the vividness of the color; lightness is the brightness of the color. By adjusting HSL, you can change the color style of the image. For example, increasing the saturation of vegetation in a landscape photo can make the green more vivid and enhance the visual impact of the picture.
◦ Operation: Also find the "Hue/Saturation" option under the "Image" - "Adjustment" menu. After opening the dialog box, you can adjust the hue, saturation and brightness separately. Adjusting the hue can change the type of color, adjusting the saturation can make the color brighter or darker, and adjusting the brightness can make the color brighter or darker.
8. Color Balance
◦ Function: Used to adjust the color tendency of the image, so that the image switches between warm tones (such as red, yellow) and cold tones (such as blue, cyan), or balance the color between different color areas (such as highlights, midtones, shadows). For example, in a portrait photo, if the person's skin color looks cold, you can adjust the color balance to add red and yellow to the midtone part to make the skin color look warmer.
◦ Operation: Open the dialog box through the "Image" - "Adjustment" - "Color Balance" menu. There are three tabs: Highlights, Midtones, and Shadows. You can adjust the color tendency in these areas respectively, and change the color balance of the image by dragging the corresponding color slider.
4. Crop and Transform
9. Crop
◦Function: Remove unnecessary parts of the image and change the composition of the image. For example, if there are a lot of messy backgrounds in a photo, cropping can highlight the subject, or crop the photo into a specific ratio, such as a square, golden ratio, etc., to enhance the beauty of the picture.
◦Operation: Find the crop tool in the software, drag on the image to create a crop frame, adjust the size and position of the crop frame, and press the Enter key or the Confirm button to complete the cropping when you are satisfied. The crop tool can usually also set a fixed crop ratio, such as 1:1, 3:2, etc., to facilitate users to crop according to specific requirements.
10. Transform
◦Function: You can scale, rotate, distort, bevel, etc. on the image. For example, when making a poster, you need to tilt a picture to increase the sense of movement, or enlarge an element to highlight its importance, you can use the Transform tool.
◦ Operation: In Photoshop, use the various options under the "Edit" - "Transform" menu (such as scaling, rotating, distorting, etc.) to perform operations. After selecting the object to be deformed (it can be the entire image or a layer), drag the corresponding control points to achieve the deformation effect, and press the Enter key to confirm when completed.
