Capturing screen shots of software products, web sites and other on-screen items to be included in your media productions, is a common enough task and may initially seem to be fairly straightforward. However, without some fairly simple preparation, the final results can look lackluster or just plain bad. I’ve read articles which focus solely on the software to use, but while selecting the right tool is a necessary prerequisite, it takes a bit more than that to get great screen captures.
Here are some tips for getting great screen captures for use in any kind of media production. Electronic forms of production (e.g. web and PPT) are a bit more tolerant of weaknesses in the process than print, but by aiming for a print standard of quality in the original screen capture, the resultant images will be great for just about any usage.
Contrary to popular belief, graphic images do not have a meaningful dpi (or ppi) measure. They have width, height and depth (color) yielding a pixel count with each pixel representing a unique color in a color model. The number of bits per pixel (bpi) is also referred to as color depth – more bits equals more available colors.
Some file formats include dpi information, along with other metadata, stored inside the file. This metadata however, merely provides guidance to software applications about the intended use of the image; it means very little in practice and can be changed very easily, with no actual change to the quality or size of the image.
It is important to note that dpi and ppi are not interchangeable measures (and they are frequently misused); generally speaking a pixel is comprised of several dots; on a conventional display for example, a pixel is made up of a red, a green and a blue dot. It is more common to speak of the “pixel” resolution of a screen, and it is more common to speak of the “dot” resolution of a printer. There is great variability between printer types and manufacturers and of course professional printing equipment. dpi and ppi become relevant only when the image is displayed or printed as it is the resolution of the display device or printer which determines how large an image of fixed dimensions will appear. Despite the fact that dpi and ppi are not strictly interchangeable, you can use an approximate rule of thumb, as a 300×300 pixel image on a 150dpi printer will print as an approximate 2” square, on a 300dpi printer as an approximate 1” square, on a 96dpi monitor as an approximate 3” square. Common screen size today is 1280×1024 pixels called SXGA or 1.3 Megapixels. So a full sized screen capture at that resolution sent to a 300dpi printer will usually produce an image of approximately 4.3” x 3.4”. Bottom line: the more pixels you can capture at the very start of the process – the greater likelihood of getting good quality in the final production. Read more …