DPI versus PPI, Know the Difference.
No one is an expert in every field, and many of us are not experts in technology. The technology field is always changing which makes it very difficult to keep up with. Fortunately, there is always ways to improve upon our knowledge base. Have you ever been curious as to what a dot is, or what a pixel is? Ever wondered what the difference is? Or how one or both might affect your image’s quality?
Many people have probably heard of DPI which stand for dots per inch, which describes how much ink is required for each pixel. When you print an image with a higher DPI it results in a better looking image, although it takes longer to print as well as using a significantly greater amount of ink. Lowering the DPI can save you a bundle on your ink cost. Every time you reduce the DPI by half you are only using one fourth of the ink because DPI is determined by multiplying the width and the height. For example, you normally print at 150 DPI which is 22,500 dots per inch, halving this to 75 DPI will result in 5,625 dots per inch which is only a quarter of the amount.
Today the term PPI is the more popular term, meaning pixels per inch. This definition has not been around nearly as long as DPI though. When you change the PPI it is normally reflected in the size of the printed image. There are two ways that changing PPI can affect an image. Whether or not you re-sample an image has a great effect on the PPI. To put it simply, if re-sample is off, proportions are constrained and changing the PPI of an image also changes the width and height of that printable image. Don’t forget that when you change the PPI, you are just changing how big or small the print size is, not the actual on-screen size. If you want to adjust the on-screen size you will need to res-sample the image. When you use re-sampling you are reducing the resolution which changes the actual image size on the screen. Images found on the internet have typically been re-sampled from the original. Cameras and scanners produce images at PPI larger than most websites will display. By re-sampling the image you less then PPI which makes a more web-friendly image.
Both terms are effect the quality of the image and how it is displayed or printed but they aren’t interchangeable. However, do not be surprised to find these terms used incorrectly. DPI is often mistakenly used when PPI is should be used, this is normally because the term DPI has been around for a much longer time.
Now that you know the difference between DPI and PPI, you’ll need some cheap printer ink which you can find at http://www.123inkjets.com.
Lee Brackenstein is an avid enthusiast in the fields of technology and photography.
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