Posts Tagged ‘Pixels and Resolution’

Digital Photo Editing – What is Digital Resolution?

Monday, January 18th, 2010

Have you edited a photograph on your computer and when you went to print it, it was just a tiny image on the page?  Ever wondered why your mother’s e-mail in-box rejects the photos of your kids ?

If you are just getting started with Digital Scrapbooking, then this elementary lesson is for you.  It is simpler than you might imagine.

Digital Resolution

A pixel is the name of the tiny dots that make up an image. The word “pixel” is computer speak meaning picture element and generally is the smallest part of any type of digitally represented image.  People are easily confused because the word pixel assumes subtle differences in meaning depending on the context in which it is used such as in printed images or the megapixels in a digital camera.

To simplify this discussion, just think of a pixel as a tiny point of light or color representing a very small component of a much larger image.

People also talk about resolution when referring to pixels.  Resolution is a measurement of how many pixels fit into a certain defined space. You may have heard of “dots per inch” (DPI) or “pixels per inch” (PPI) and the meaning of these two terms adds to the confusion because once again it depends on the context in which the term is used.

Let’s simplify once again by saying that image resolution is an expression of how much detail an image holds.

Our televisions, computer displays, cell phones, and even digital cameras are full of pixels – thousands and thousands of them all crammed together so closely it fools the human brain into thinking these tiny dots are a smooth image.  These digital images appear just about anywhere we look in our technology filled world, from our PDAs to our car dashboard to the giant electronic billboards on display along the highway or in New York’s Times Square.

The more pixels in an image, the smoother the picture looks.  On the other hand, if the number of pixels is too low, the image quality degrades.  So you may be able to distinguish the individual dots in a microwave display but a printed digital photo looks as smooth as glass.  A pixelated image results when the pixel count is so low, you can see the jagged edges.

Digital cameras have made sharing photos easier than ever.  No longer do you have to get film developed and multiple copies printed.  Today, many people share their photos through email and social network sites. However, before doing this the image taken from the digital camera is usually downsized.

Digital cameras are built to duplicate film camera quality and therefore capture images with a huge pixel resolution. Compare that to nearly all home computer screens that have a low pixel count, normally under 100 pixels in an inch.  Displaying high resolution images on a low resolution device results in an image that appears much larger on the computer screen.  Digital cameras capture images at high resolution to make possible photographic quality prints. But e-mailing this large image file will use megabytes of data and many e-mail clients will disallow it.

Image Resampling

The answer is to resample the image which is computer speak for altering the resolution.  Decreasing the pixel count will make the image appear normal on a computer monitor.  And this will allow you to e-mail Mom with the hottest family photos from your latest vacation.  But after resampling the image, don’t expect to get a good photo any longer since you’ve taken out too many pixels.

So here is the fundamental point to remember. Digital images that will be printed need to be at a high resolution while images displayed on a computer monitor need only a low resolution.

If you choose to do both of the above, make a copy of your original digital image for experimenting with.  Besides allowing for both printing and viewing images correctly, this is also a well  recommended backup plan for all of your digital photographs.

Now you are ready to take lots of digital photographs and be able to print and share them without further hassles.