|
Adobe Photoshop is the definitive digital imaging software. The full version is about $600. You might find an older version (5.0, 5.5) on Ebay for a reasonable price, but be sure it's the full version you're buying, not an upgrade. Elements (version 3-on) has the really vital functions. Magazine articles about digital imaging talk in terms of Photoshop, so you would do well to learn the basics. Alternatives to Photoshop that many people like are Paint Shop Pro, by JASC, and Ulead PhotoImpact 12.A computer made in the last five years with at least 500MB of RAM should be sufficient. If you plan to process RAW images or scan at high resolutions, you need about a Gig of RAM, minimum. Here's a Simple Beginner's Work Flow to Get You Started!
Fixing contrast and brightness is a one-button fix in simple softwares, but Photoshop gives you two main ways to go about this, Levels and Curves. For a clear, concise rundown on Levels, visit Sean McHugh. He has great tutorials on his site that tell you exactly how to do this and much more.
brightness and contrast tweaked, boat gone |
The other tool for brightness and contrast is Curves. Grabbing the center of the slope and pulling up or down adjusts the mid tones. A shallow "S" curve increases contrast and a shallow reverse "S" decreases contrast. You can keep some part(s) of the curve stationary and tweak other parts. Your scans or digicam captures will sometimes have a color cast, which is too much or too little of certain colors. The wedding example above showed blue in my shirt. I greatly enlarged the image and found the very brightest white I could find, the white from one of my wife's pearls. I clicked on this pure white area with the white eyedropper in Curves (setting a 3-pixel sampling size in Window/Eyedroppers), and all the tones fell into place. Try this if you think you have a color cast. Simply Undo it if you don't like the result. Some images actually benefit from certain color biases, as the original scene is properly rendered with such a bias. I am in the learning process on color correction myself, but I can tell you that you will develop your eye if you are patient.
If you scanned film at a high color bit depth, or if your high-end digital camera returns RAW, do your tonal and maybe color correction first. This way, you have the high-bit information in your image to do the best job of tonal correction. If you are satisfied with your tonal and color correction, go to Image, Image Mode and reduce the bit depth to 8-bit to save storage space. You will see the file size drop by half. Many digicam shooters can ignore this bit-depth tapdance, as your captures are already in 8-bit. Recent editions of full Photoshop allow you to do your tonal and color edits on Adjustment Layers in the high bit mode. Save the image as a PSD, thus preserving your layers. This way, you can tweak these settings later, or throw them out and start over. This will not degrade the original image on your Background Layer in any way. The file sizes will be huge. Those of us with older editions of PS will have to drop to 8-bit color before we can do adjustment layers or other edits. Your imaging program lets you size your image for its intended use. In Photoshop, it's done in Image Size. On this screen, you will see your total file size (in megabytes), your resolution, (density of your pixels, in pixels per inch), and the dimensions of your image (in pixels or in inches, set as you prefer). DO NOT check Resample. Check the Constrain Proportions block always.
Now you can change the image dimensions, OR the resolution (not both), and simply watch what happens to the other factors. Set the image width to 7 inches, if it's a 5 x 7 you want, and the program will calculate the height and resolution for you. You can set the resolution (let's say your printer likes 240 ppi input), and you can watch the image dimensions change. You will not be degrading the image in any way. You need not save the change you made. If you did by accident, simply Undo it.
Here's when to use Resample: you can let your software throw out some pixels if the file size is too big for the web, or to send your picture via e-mail. Resampling down, ie. making the file size smaller, is not a problem, as long as your result fits your purpose. Be sure to save a full-resolution version of any image you want to keep for printing or archiving before you do this. For the web, change your resolution to about 72 ppi, and make the pixel dimensions fit the screen size you want, 750 pixels across the long dimension being a starting point. Be very careful about situations in which you need a larger file size than you have. Resampling up, or letting the software add pixels, never results in a better image, although you MAY get away with it. Treat Resample in Photoshop as you would a chainsaw; stay away from it unless you have a very good reason to mess with it. Converting to JPEG for the web and e-mailing are good reasons.
Images scanned from film or prints often have distracting dust spots, or unwanted detail (See the boat in the wedding picture above). Even Digital Ice and other clean-up programs can leave imperfections from the "cleaning" process. Any imaging software can clone similar pixels to lay over these spots. The icon for this in Photoshop looks like a rubber stamp. Finally, sharpen your image to recover sharpness lost in scanning, cropping and in changing the file size. The RIGHT tool for this is under Filters/Sharpen/Unsharp Mask. Wayne Fulton at www.scantips.com gives you parameters for setting Unsharp Mask that work quite well for me. Some imaging programs give you only one Sharpen option, with no control over the degree of sharpening. This has a meat axe effect, often overdoing it. If objects have a white fringe around them, or, people have halos who don't merit them, you've overdone it. Be sure your imaging program gives you this flexibility in the sharpening function. If sharpening makes defects such as dust spots more apparent, you can mask areas of the image, such as sky, to which you don't want sharpening applied.
|
