Many people have seen them but there are still some who don’t know what a photo is, but the following information should establish some facts. The focus here will be to answer the question “what is a digital photo?”
All digital photos are made up of picture elements called pixels. The number of pixels in a photo determines its size i.e., “1520 x 1280”, “800 x 600”. The width of the photo is the first number, while the second number tells you its height. Note that the term pixel also refers to a digital camera’s image sensor elements.
The term megapixels refer to the resolution of a digital photo. To be more specific it denotes the total number of pixels in the image. If you take a photo measuring 2048 x 1536 pixels, it has 3,145,728 pixels which are usually rounded of as 3 megapixels.
If you took a picture with a size of 5184 x 3546 pixels, its resolution is 18 megapixels (18,382,464 pixels). If you are shopping for a digital camera, check its megapixel because this will tell you how high a resolution you can use.
No matter how high the image resolution is, the resolution of your computer monitor will determine how much of the photo you can see. If your monitor can only display 1024 x 768, that high res photo you took will be shrunk to fit in the screen, or you will have to scroll down to see the rest of the image.
Resolution, DPI and PPI
To make it clear, a digital photo’s resolution refers to the number of pixels it has (width and height). DPI (dots per inch) and PPI (pixels per inch) are sometimes referred to as an image’s resolution, which is incorrect.
DPI refers to printer resolution, and it has no connection with a digital photo’s resolution. PPI on the other hand, is the digital photo’s printed output resolution. What makes this even more confusing is that some software manufacturers use DPI and PPI interchangeably when they are two different things.
The RGB System
The majority of digital images use the 24 bit RGB system to provide color for every pixel. This means that all the pixels have 256 color gradations of blue, green and red. For example, light pink has 204 blue, 153 green and 255 red, while orange is 0 blue, 102 green and 255 red. By adjusting the values in the RGB system, 16 million colors can be reproduced, around the same number that the human eye can distinguish.
Don’t be confused if you see computer displays claiming it can produce 32 bit color. It is really 24 bit RGB with a transparency (alpha) channel. To see photos in 24 bit RGB, your graphics card and monitor must be able to support it.
The more pixels there are in an image, the higher the resolution and the sharper looking the image will be. But resolution is only one factor, the quality of the camera will also come into play as well as the digital format used.
As you can see, there are a lot of terms associated with the topic. The question what a photo is seems simple enough, but there are actually a lot of factors and elements that you need to consider.
About the Author: Tom is a freelance writer and content builder of http://www.askdeb.com/ and nowadays he is doing work on Digital Photography.