Digital Image Formats
Nowadays we take pictures with a digital camera or digitize snapshots with a scanner and view the results on our computer screens. We can then attach the images to outgoing emails or post them on the Internet for all the world to see.
Regarding editing, anyone who buys a scanner or digital camera normally gets some photo-editing software with the hardware. However, these programs tend to vary considerably in their terminology and procedures, which makes it difficult to offer specificd instructions on their use in this column. Beyond that, new users are often bewildered by all the options these programs offer and often settle for viewing and/or printing a photo just as it comes from the scanner or camera.
In other columns I've given tips on editing photos with Windows Paint, only because it's a program that comes with all versions of Windows.
However, its bitmap-editing features are severely limited. For this reason, I'd suggest using a couple of more robust programs: Irfanview, which is free from Irfanview.com and Picasa, which is free from Picasa.google.com.
And if you are looking for a place to organize and share your photos online, try
Digital Picture Formats
While downloading these programs you'll be asked which graphic formats you'd like to have associated with each program. I definitely recommend checking off JPG, BMP, GIF, TIF, and EPS to be the defaults in Irfanview. This means that a graphics with any of these extensions will immediately appear in Irfanview when double-clicked.
Since Irfanview does not come with a manual, I don't pretend to be an expert on using all its advanced features. However, I can explain how to use some of the features most often needed by the average computer user. Others more familiar with the program are invited to send me tips, which I'll gladly share in these columns.
Let's start with picture "size." It's important to understand that the "screen view" size and "actual" size are not necessarily the same. The former can be adjusted to make things easier to see and edit on your monitor, while the latter is the actual finished size that your printer will output on paper.
Double-clicking a picture's icon will cause it to appear in Irfanview at a 100% screen view, which, in theory, will be the same size of an actual printout. However, since monitors come in many sizes and resolutions, the theory doesn't always hold true.
If you want to increase or decrease the screen view, clicking on the Plus (+) or Minus (-) icons in the Toolbar will make the image change in 10% increments. If you want to increase or decrease the print size, go to Image>Resize/Resample and type in the appropriate numbers, keeping in mind that a size of 600 pixels high by 800 pixels in width will take up most of an 8-1/2" x 11" sheet of paper. By having "Preserve Aspect Ratio" checked, you need only change the width or height to have the other dimension adjust itself accordingly.
Which DPI to Use
The default DPI (dots per inch) will usually be 72 or 96, which are adequate for being viewed on one's screen — but changing them to 300 will produce a much sharper print image.
If you do change the print size, be sure to go to File>Save As and give the resized picture a different name. This will preserve the original, in case you need to use it again with its original properties.
Selecting a Portion of a Picture
If you want to crop a portion of a picture, Irfanview comes up in the "Select" mode by default. This means you can draw a rectangle around the part of an image you want keep by moving your mouse with the left button held down. Next click on Edit>Copy (or do Ctrl+C), followed by doing Edit>Paste (or Ctrl+V). This will cause the section you just cropped to appear in a new window by itself.
If you want to adjust the colors of your picture go to Image>Enhance Colors. This will give you two small copies of the picture — one showing the colors as they currently appear, while the other shows the results of using the sliding adjustment levers that change the Red, Green and Blue values along with the Brightness, Gamma and Contrast factors. You can always undo things by clicking on Set Default Values, in case the options seem to be getting out of control.
Picasa has similar image-editing options and they are equally easy to learn and use. Thse free programs are definitely worth having and experimenting with.