Number 237 - February 2003

A Brief Introduction to Digital Photography Part III - Edit Your Photographs
by Richard P. Ten Dyke
In Part I, we discussed getting a photograph into digital form, and in Part II, (Jan 03) storage and compression. Now we will discuss editing and improving your images.    Taking pictures is only one part of the creative process. After you have your image in digital form, you will almost certainly want to make modifications to improve it. Very few photographs are perfect when they come out of the camera. To modify or edit an image, you will use photo-editing software.    Some of the more simple editing functions may be included with software that comes with the digital camera or scanner. These might include cropping, improving contrast and brightness, and removing redeye.    Many times more needs to be done, and you may want to use a more sophisticated software package. The most widely used photo editing software package is Photoshop, by Adobe . The current flagship program is Photoshop 7.0 , which sells for $600. Recently, Adobe released a reduced-function version called Photoshop Elements . To say it is reduced - function fails to give credit for the richness of function that it provides--about equal to their then flagship product of just a few years ago. Elements is all that you will need; it runs on a Mac or a PC and it sells for less than $100.    Another excellent editor is Picture Publisher, offered by Corel , priced at about $100., but runs on a PC only.    Regardless of your choice, any of these editors offer all the functions that a non-professional user could want, and more. Here are some of the ways that I have used photo-editing software in recent days. Correct minor problems, such as eliminating spots, eliminating power lines, removing glare from glasses. Do a better job of correcting problems of under- and overexposure. It is possible, for example, to lighten a specific area of a photograph, while leaving other areas untouched. This will allow you to pull detail out of shadows, or soften highlights. Soften wrinkles in a photograph of a person. Clean up skin blemishes. Create a composite of photographs to be used in a publication. Straighten vertical and horizontal lines, and correct distortion in buildings or other large objects. Combine parts of two separate images to merge the best parts of each into a single image. (I have done this with group photos to (hopefully) end up with a picture where everyone had their eyes open and is smiling). Adjust the pixel dimensions when placing the image on the Internet, in order to control download time.	Make proof sheets to view multiple images, for reference purposes. Create a panoramic image by combining two separate "left-and-right" images of the same scene. Add text.    And the list goes on . . .    These are simple ways to correct defects, or slightly improve on the original image. I have not mentioned many of the ways one can use photo-editing software to become extraordinarily creative. One can rotate and distort images, cause multiple images to blend into one another, and add a wide variety of text and graphic effects. In fact, when the artist in you starts to take over, what you end up may not resemble a photograph at all.    To do these things takes practice, of course, but the programs come with tutorials and documentation, and numerous text books are also available. The quality of your photographs will show the difference, and your rewards will be worth the effort. Remember, when you say "Oh I would never want to do anything like that," it is probably because you didn't know you could do it, or how much fun it would be.    All photo-editing software works with an uncompressed image. If your photo is in your computer as a compressed jpeg file, it will be expanded to its original pixel dimensions when it is loaded into your photo editor. I know of no photo editor that works with compressed images. (There have been attempts, however.) If your uncompressed image is 5 megapixels, it will translate into 15 megabytes of memory. Your software will also be saving copies of pre-edited images to make use of its "undo" features, so you will need available memory that is three to five times your image size, or performance will suffer. Machines come loaded with lots of memory, so this is not a problem with newer machines, but it was a problem for older ones. Professionals often work with images that are 100 megabytes and greater, so machines with a gigabyte of main memory are common in the industry. You will probably not need more than 256 Megabytes to do your work, and I sometimes use a PC with Windows 98 using 96 Megs.    In our next and final section, we will discuss questions concerning printing and displaying our images.    Richard Ten Dyke is a member of Danbury Area Computer Society who has had a long interest in both photography and computers. He started his photography career with a Leica IIIC in 1952, and his computer career working with an ERA 1103 in 1956. He currently is retired from IBM and resides in Bedford, New York. You can reach him at Copyright (C) 2002 Richard P. Ten Dyke
Number 237 - February 2003