BASIC PHOTO EDITING WITH ADOBE PHOTOSHOP This handout will help you adjust your photographic images so that they look more natural. There are eight steps to basic image editing with Adobe PhotoShop. They are: 1. Rotating 2. Cropping 3. Adjusting Color 4. Adjusting Relative Brightness 5. Adjusting Contrast 6. Adjusting Saturation 7. Adjusting Sharpness 8. Saving for Web and Print You may find that you do not need to do all of them. You will almost always need to Crop, Adjust Color, and Adjust Brightness. You will always need to Save your image when you are done. ROTATING AN IMAGE Sometimes you need to rotate a digital photograph because the photographer accidentally tilted the camera when taking the picture. You may also need to rotate an image that was placed on the scanner bed at an angle. Rotation is a very easy task. Go to the IMAGE menu and choose ROTATE CANVAS. You may rotate the canvas 90 degrees in a CW (Clockwise) or CCW (Counterclockwise) direction. You may also rotate the canvas 180 degrees. You may choose to rotate the canvas in increments other than 90 degrees by choosing ARBITRARY. ARBITRARY asks you to enter an angle of rotation, and choose clockwise (cw) or counter- clockwise (ccw). You may enter any number, 0-360, or a fraction of a degree, such as.5. You may have to use the ROTATION tool a few times to get the proper rotation
CROPPING A PHOTO Cropping a photo allows you to eliminate extraneous material and refine the focus of the image. Below on the right is a photo that has been adjusted and cropped to create a completely new view. The Cropping Tool is located on the PhotoShop Toolbar. It is the fourth tool down from the top. To use the Cropping Tool, select it and click and drag with it on your image. When you let go you you will see dashed lines with handles. You can move the handles to define an area to keep. When you have selected the area you want to keep, double-click to activate the crop.
ADJUSTING PHOTO COLOR WITH VARIATIONS There are several tools to help you adjust the color of an image: Variations, Color Balance and Curves. Some of the experts suggest that you start with Variations. Here s an image with a strong reddish cast, badly in need of color adjustment. Using Variations Go to the IMAGE menu, select ADJUSTMENTS and select VARIATIONS (it s at the bottom of the Adjustments sub-menu). The Variations panel appears. The Variations panel is designed to give you a visual preview of color adjustments you can make to your image. IMPORTANT: When you first open Variations, you must click on the Original image in the upper lefthand corner. Variations is designed to remember the settings you used the last time you opened the Variations panel, and to start there. By clicking Original, you will eliminate this setting. The Variations panel is designed to show you what your image will look like if you add more of a certain color More Red, More Green, More Blue, etc. To reduce the intensity of a color, click on the opposite color. For example, to reduce the amount of red, click on the More Green button. To reduce the amount of yellow, click on the More Blue button, etc.
At the top of the Variations Palette are some important settings. The first is the Original and Current Pick images at the upper-left-hand corner. The Original shows your original image. Current Pick shows the changes that you have made to your original image in the Variations menu. Be sure to click on the Original image when you first open Variations, otherwise Variations will reflect the last changes made. In the center is a radio button list of Shadows, Midtones, Highlights and Saturation. Variations will adjust only the colors in the group that you select. Shadows include black and colors closest to black. Highlights include white and colors closest to white. Midtones is the larger group of colors between black and white. By default, Variations selects the Midtones when you first open it. Generally speaking, you should start your adjustments with the Midtones. Below the buttons is a slider from Fine to Course. This will increase or decrease the intensity of the effect Variations will have on your image. By default, the slider bar is in the middle. When you are done adjusting colors in Variations, click on the OK button. If you make a mistake in your adjustments, you can click on the Original and restore your settings to your original image.
ADJUSTING PHOTO COLOR WITH COLOR BALANCE Color Balance is another tool you may use to adjust image color. It is located under the IMAGE->ADJUSTMENTS->COLOR BALANCE menu. Color Balance works just like Variations, except you do not get a visual preview of your changes. One benefit of Color Balance over Variations is the ability to adjust more finely the application of color correction. You may want to use Color Balance on your image after you have tried Variations in order to get a more precise color correction. ADJUSTING PHOTO BRIGHTNESS WITH LEVELS Levels is a very powerful tool for adjusting the relative brightness of an image. The Levels palette has two parts the Input Levels on the top and the Output Levels on the bottom. The Input Levels is the only part of this tool we will use,
The levels graph called a histogram shows the distribution of shadows, midtones and highlight colors in an image. The majority of the colors in most images will be in the middle, where the midtones are. You can adjust each of these color groups by sliding the triangles below the histogram to the left or the right. The black triangle on the left represents the shadows. You can slide this triangle to the left to increase the darkness of the shadows. The white triangle on the right represents the highlights. You can slide this triangle to the right to increase the brightness of the highlights. The grey triangle in the middle represents the midtones. You can move this to the left to increase the brightness of the midtones, and to the left to darken. Generally speaking you want to start with the midtones. Drag the grey triangle to the left to see the changes. If your image needs additional brightening, drag the white triangle slightly to the left. Finally, it is usually a good idea, after brightening your image, to darken the shadows slightly by dragging the black triangle to the right.
A Word About Clipping Clipping occurs when the highlights of a photo are over-brightened, resulting in noticeable segments of the highlights turning pure white, instead of reflecting a range of lighter tones. Clipping also occurs when the shadows are over-darkened, resulting in noticeable segments of the shadows turning black. Sometimes clipping is easy to see, like in the image on the right, where the highlights are clearly clipped. Sometimes it is more difficult to tell when the highlights or shadows are clipped. Fortunately, there is a super-secret command hidden in the Levels palette that lets you see if your highlights or shadows are clipped. On the Mac, if you press the Option Key while clicking on the White Triangle in the Levels Palette, your image will show you which areas, if any, have clipped highlights. The areas of your image that appear pure white are clipped. If you press the Option Key while clicking on the Black Triangle, your image will show you which areas, if any, have clipped shadows. The area of your image that appear pure black are clipped. (Use the Control Key on Windows machines.) If you are knowledgeable about how the Color Channels work, you can apply adjustments like Levels to individual Color Channels, affecting only the reds, the blues or the greens. This gives you even more control over the amount of lightening and further prevents clipping. For more information, check out the PhotoShop Help System under the HELP menu.
ADJUSTING CONTRAST The easiest way to adjust contrast is with the Brightness/Contrast panel. You may use this panel to adjust the brightness of your image, but it is not recommended because you do not have the ability to adjust the highlights and shadows separately from the midtones. To increase the Contrast, move the slider to the right. You may also use this to decrease the contrast of an image by moving the slider to the left, but you will very rarely need to do this. Contrast increases the difference between the lighter and the darker areas of your image. Generally speaking, you want to use Contrast to adjust an image that looks muddy. A good use of Contrast will add clarity to your image. Never click the Use Legacy option in this window. It introduces clipping in the highlights and the shadows.
ADJUSTING SATURATION After adjusting the color and brightness of an image, you can sometimes improve your image by boosting the saturation slightly. The easiest way to adjust the saturation of an image is with the Hue/Saturation panel. You may also use this panel to adjust the brightness of your image, but use Levels first. To increase the saturation of an image, move the Saturation slider to the right. Occasionally you will run into an image that is too vivid, or overly saturated. You may use the Saturation panel to reduce saturation by moving the Saturation slider to the left. The Saturation panel, like the Levels panel and the Curves panel, will let you adjust the saturation or color tonality of your image based on the Red, Green, Blue or Master (combined) channels. Your lab instructor can explain how this works, or you can consult the PhotoShop Help system under the HELP menu.
ADJUSTING SHARPNESS Sharpening works by increasing the contrast between neighboring pixels. All of PhotoShop s sharpening functions are located under FILTER->SHARPEN. They include Sharpen, Sharpen Edges, Sharpen More, Smart Sharpen and Unsharp Mask. You should only use the last two functions Smart Sharpen or Unsharp Mask. We are going to use the Unsharp Mask command in this example. Amount controls the amount of sharpening that is applied to the image. Values over 100% increase the sharpness, values under 100% decrease the sharpness. Amount has a maximum value of 500. Radius controls the width of the edges that are sharpened. For Web images you usually want to keep the Radius between 0.5 pixels and 1 pixel. For print images you usually want to keep the Radius between 1 pixel and 3 pixels. However, an individual image may dictate otherwise NOTE: You should only adjust images and view image previews at 100%, 75%, 50%, 25% or 12.5% Other zoom levels will distorted the effect. Threshold helps control the noise that is introduced in the sharpening process. Threshold determines the luminosity value of pixels to be sharpened. For example, a Threshold of 0 means that all pixels will be sharpened generally a situation you want to avoid. For best results, choose a Threshold level between 1 and 10.
SAVING PHOTOS FOR THE WEB PhotoShop has a very easy method for saving photos for the Web. Simply select FILE-> SAVE FOR WEB & DEVICES. Save your image for the Web ONLY after you finish editing your image. You should also save a high-resolution version of your image with your adjustments. You will be able to edit this image. PhotoShop applies a great deal of compression to images saved for the Web, making them much more difficult to edit. File Format: First, select a file format from the pull-down menu in the top box on the right-hand side of the screen. The format menu is in the upper-left-hand corner of the first box, and the choices include GIF, JPEG and PNG. Save photographs in the JPEG format. Image Quality: After selecting the JPEG format for your photograph, set the image quality. Higher image quality creates a better image, but a larger file size. Set the image quality to the lowest level that does not adversely affect the display of the image and that gives the lowest file size. You can see the file size of your current settings on the lower left-hand corner of the Save for Web panel, underneath the image. Generally speaking, you want a file size that is under 100k for the Web. Image Size: Use the Image Size tab in the lower box on the left-hand size to change the size of the image. Reducing the image size will reduce the file size of your image. When you are ready to save your image, click the SAVE button at the top. The Save for Web Panel also automatically sets your image resolution to 72 pixels per inch, which is what you want for the Web.
SAVE FOR PRINT To save images for print instead of for the Web, you do not want to use the Save for Web and Devices menu item. Instead, you want to finish editing your image, then adjust the print size with Image Size, and then save the image with FILE->SAVE. The Image Size panel is located under the IMAGE->IMAGE SIZE menu. The important thing to remember about the Image Size panel is that the Pixel Dimensions are of interest to us only if we are saving the image for the Web. For print, you will use the Document Size settings. Preparing your image for print is relatively easy if you follow these steps: 1. Uncheck Resample Image 2. Set the Resolution to 300 pixels/inch 3. Recheck Resample Image 4. Resize your printed image by entering the desired size, in inches, in Width and Height under Document Size. (Make sure Constrain Proportions is checked.) 5. From the drop-down menu under Resample Image, select the best interpolation method for your image. Choose Bicubic Smoother is you want to make your image larger, choose Bicubic Sharpener if you want to make your image smaller. 6. Click the OK button when you are done. After you have adjusted the image size, you can save your image and print directly from PhotoShop.