Digital Photography: Understanding Image Resolution

Good photography remains as elusive and as enticing as ever -- knowing how to optimise it in your digital darkroom will only make it better.

Resolution is a term used a lot in photography these days -regardless which type of photography you do, or which type of camera you use, understanding image resolution, pixels and the different properties attributed to them is so important.

Whether you are printing, scanning or sending an image by e-mail, you need to understand and know how to keep your images sharp and preserve as much detail as possible in your final print. This topic does cause some confusion, so I hope the following will help.

Image resolution explained:

Photography resolution is a measurement of image quality, so you may define resolution by how much detail is in your print. If your print has sharp detail you may consider your image to be of good resolution. If detail is blur in your image you may consider your image to have poor resolution. Good resolution is a direct result of having a large number of pixels in an image.

Pixels explained:

Digital images are made up of millions of small dots - each dot is called a pixel. Each dot contains a small piece of image information, and when added together with the other pixels you'll get your final image.

Print resolution is measured in pixel per inch (ppi) or in dots per inch (dpi) - both hold the same value. 300dpi means that there are 300 pixels per inch or 90,000 pixels per a square inch. But as of the my experience dot per inch (dpi) are commonly use.

What size resolution should I use?

At 600dpi (which is an extremely large resolution) your image will be supreme sharp. You will be restricted with print size.

Printing your images at 300dpi is the standard quality. Image sharpness doesn't get much better. The only setback is that the maximum print size will be restricted - you might need to drop the resolution to get a larger image.

If you need a large print from a small file print your file at 150dpi - your print will lack detail and the pixels may be visible. You should not print an image any smaller than 150dpi.

72dpi is standard with your computer screen. Don't print your images at this size - the pixels will be visible.

Resolution tips:

Scan your images as large as possible; it's easy to resize them later. If you scan an image to small you may have to re-scan at a later date to get a larger print.

If you need a print that's twice the size of the original - scan it at 600dpi and print it at 300dpi.

Try to print your image at 300dpi.

If you use a tripod when taking an image you may be able to push the print resolution lower than the recommended 300dpi - this will enable you to get a larger print.