photo_improve

Workshops S T E P B Y S T E P ISSUE 69 Improve your digital photos Follow our quick and easy guide to digital image manipulation and give your photos a professional makeover 53 Improve your digital photos 56 Get Star Office for free 58 Computing for the left-handed 59 Building a home network 62 Using Functions in spreadsheets 64 Hints & tips D igital cameras and printing technology are improving all the time, and there’s no longer a need to rely on old-fashioned film for your snaps. But while it’s a simple matter to download and print your photos as they come, with a little knowledge and effort you can make subtle changes that make all the difference between a good and a great picture. The choice of the professional for this kind of work is the rather expensive Adobe Photoshop but many of its advanced features are also present in the Limited Edition (LE) version, which we’ll be using here. Always shoot on the best quality setting that your camera will allow – 640 x 480 pixels will be good enough for a web page or just viewing on your monitor, but it won’t be good enough for a decent-sized print. Andy Gibbons STEP 3 STEP 1 The first job is to download your chosen picture from your camera. Start up Photoshop LE and, from the File menu, choose Import and then Select TWAIN_32 Source, making sure that your camera is highlighted. Now from the File menu again, choose Import and this time select TWAIN_32, which will load your camera’s TWAIN driver and let you view thumbnails of the pictures stored in its memory. Double-click the image that you want to work on and it should open up in Photoshop. ¿ By default, most cameras use the highly compressed JPG file format, and you should save your picture onto your hard disk using Photoshop’s proprietary PSD file format. This uses more disk space, but retains all of the quality as well as details of the layers and alterations that you might make. From the File menu, choose Save As and in the Save In dropdown box, navigate to the My Documents folder. Choose a descriptive filename and select .PSD as the file type. You can also place a tick in the Save Thumbnail tickbox, which will use the actual image as the file’s icon when it is viewed in a normal Windows folder. STEP 2 The next task is to decide just how big the image needs to be. We’re going to aim for a standard 6 x 4in print and, as most inkjet printers show little improvement at resolutions of more than 200 dots per inch (dpi), we can reduce our image down to the finished size before we go any further. Image editing is an intensive task for your PC’s memory and processor, so this should speed things up. From the Image menu, select Image Size and change the resolution to 200dpi before clicking OK. Use the Ctrl-R key combination to show Rulers and you’ll be able to gauge the size of the image at 200dpi. 5 O C TO B E R 2 0 0 0 / computeract!ve 53 ILLUSTRATIONS BY: SPIKE GERRELL ¿ ¿ Workshops S T E P B Y S T E P STEP 4 Now we want to get rid of extraneous areas around the edge of the photo and cut it down to 6 x 4in by cropping it. At the top left-hand corner of the floating toolbox, you’ll find the Marquee tool. Click on this and keep the mouse button depressed until the flyout box appears. This provides access to an even greater range of selection tools including the Crop tool on the far right. Select this and drag out an area slightly larger than 6 x 4in, which shows the subject of the picture to its best advantage. ¬ From the Layer menu, go to New Layer and select New Layer Via Cut. This removes the sky from the picture and places it on a separate layer. Now that the sky is on this new layer, turn it off by clicking on the small eye icon in the Layers palette. Ensure that the background layer is highlighted and, from the Image menu, select Adjust and then Variations. STEP 10 54 computeract!ve / 5 O C TO B E R 2 0 0 0 ¬ ¬ If all is well you can press Return to crop the image, but in some cases you may need to reduce its size to fit the subject comfortably into the intended area. To do this, open the Image menu and then select Image Size. Ensure that Resample Image has a tick next to it and then type a slightly lower value into either the Height or Width boxes under Print Size. Click OK and then crop the image until you get exactly the required size. You might find it easiest to concentrate on the width first and then get the height right. Once you have both dimensions right and you’re happy with the positioning of the subject, save the image with a new name. STEP 5 ¿ ¿ STEP 6 Now we’re ready to look at our picture and think about how it could be improved. Probably its most obvious fault is that it’s quite dark as a result of being taken on an overcast day and there are very few highlights. We can correct this to some extent by using Photoshop’s Levels feature. This is accessed from the Adjust option in the Image menu, and shows the distribution of pixels throughout the image. By looking at the histogram we can see that, in our example, there is a lack of white tones and this can be corrected by clicking on the Auto button. This makes the darkest pixel in the image black and the lightest one white, increasing the contrast accordingly. ¿ STEP 8 STEP 9 ¡ Feel free to experiment with different values but be aware that due to the resolution limitations of computer monitors, the effects appear much more pronounced on screen than they will in the final print. The natural tendency will be to under-use USM but the Photoshop manual provides some useful printed samples, showing the effect of varying levels. A common problem with both digital and scanned images is that they are never quite as sharp as their traditional counterparts and most images will benefit from Unsharp Masking (USM). This is an effect used for sharpening edges to compensate for blurring both in the captured image and the printing process. From the Filter menu, select Sharpen and then Unsharp Mask. In the dialogue box that appears, choose an amount of 150 per cent, a radius of one pixel, a threshold of zero and then click OK. STEP 7 The next stage is to tackle the lack of shadow detail. But before that, we’re going to separate the sky from the rest of the image so that it doesn’t suffer as a result of our changes. Use the Magic Wand tool to select the sky. Adjust the tolerance if needed and, if you need to select additional areas of the sky, hold down the Shift key as you click on the image. STEP 11 This is probably one of Photoshop’s most interesting features, enabling subtle changes to both colour and brightness to be made and compared with the original. Drag the slider to the left towards Fine and select Shadows. We want to brighten these slightly so we’re going to click on Lighter until some noticeable detail starts to appear in the darker areas of the picture. Click OK when you’re happy with the result and then make the sky layer visible again so that you can see the overall effect. PAINT SHOP PRO 6 Don’t worry if you don’t have Photoshop LE as all of the techniques used here can also be achieved in Paint Shop Pro. The menus and dialogue boxes may differ but, under the hood, both programs are quite similar. Rulers are accessed from the View menu and instead of Image Size, Paint Shop Pro uses Resize, which works in the same way. The Levels dialogue box is also here, but must be accessed by creating a new adjustment layer and selecting Levels. Unsharp Masking can be found in the Sharpen section of the Filter Browser under the Images menu. Layers work in the same way as in Photoshop, but instead of the Variations menu you will have to use the Brightness and Contrast dialogue box, which is accessed through the Adjust option in the Colours menu. The gradient fill effect involves a slightly more complicated procedure and can be found in the Flood Fill Tool Options dialogue box. When it comes to saving your work, you will find that Paint Shop Pro also has its own proprietary file format (PSP) which saves layer information and adjustments. √ STEP 12 Now select the sky layer and decide what you’d like to do with it. The options here range from lightening or darkening it, to replacing it with another sky entirely. We’re going to add a blue gradation to add a bit of colour but first we need to copy the sky layer. In the Layers palette, drag the sky layer onto the New Layer icon to the left of the wastebin and an exact copy will appear. Turn off the background and original sky layer and, using the Magic Wand tool, click in an empty area of the image, shown by a grey and white checkerboard pattern. From the Select menu, choose Inverse and then hit the Delete key. This will remove the sky but leave us with its shape still intact. Turn the background and original sky layers back on, and don’t worry if your clouds have vanished. Just drag the Opacity slider in the Layers Palette to the 30 per cent mark and you’ll see a more natural effect. You could turn off the original sky altogether if you wanted a clear sky or you could follow step 12 by pasting in another image entirely. The world really is your oyster and the beauty of the Levels Palette is that you can easily switch between multiple versions and delete layers you don’t want by dragging them onto the wastebin icon. STEP 14 ¡ JARGON BUSTER Dots per inch (dpi) The way resolution of scanned and printed images is measured. Both are made up of tiny dots. The more dots there are per inch, the better the image. ¬ Now we’re going to select two blues to represent the top and bottom of the sky. The Colour Picker dialogue box normally shows black and white but, by clicking on both of them in turn, you can select any colour you like. Next, click on the Gradient tool (above the eyedropper) and, making sure that Foreground to Background is selected, drag a straight line from the top of the sky to just below its lowest point. Release the mouse button and you will see the sky area filled with a smooth blue gradient. STEP 13 STEP 15 All that remains is to compare the finished result with the original and print it. It would be a shame to go to this much trouble and then use cheap paper, so use good photo quality paper, and ensure this is selected when you hit Print. Histogram A bar chart used by graphics programs to show the distribution of tonal values in an image. Layers By creating effects on separate layers of a processed image it is easier to change individual elements without affecting the whole image. Thumbnail A miniature graphical representation of an image used in image-editing packages as a quick and easy way of viewing the contents of graphics files. ¡ √ TWAIN A standard way for scanners and digital cameras to talk to your computer. 5 O C TO B E R 2 0 0 0 / computeract!ve 55