Understanding Basic Resolution

Understanding Basic Resolution

by Carolyn Bright

Resolution: the number of pixels used to capture an image, which dictates how much detail is captured.

The higher the resolution, the greater the detail, especially at larger print sizes. Reducing a picture in physical size to increase clarity will not be necessary after a certain point, as the pixels will have become too small already to see individually with the naked eye.

Pixel dimensions: horizontal and vertical dimensions of a picture in pixels.

How It Works

A digital camera captures pixels—squares of colour—which make up the image. Each pixel is a uniform colour, which means that for detail to appear, there must be a great many pixels to show it—the more pixels, the more opportunity for colours to blend properly, and appear in their proper proportions. If there are a great many pixels, they will be physically smaller and more numerous on screen. This will make the image clearer, show finer detail and reduce or eliminate ‘pixelation’, which is what happens when the pixels appear so large as to be actually visible as squares. Small details in a low-res picture will be blurred, or not appear at all, while they appear in clear focus in a high-res picture.

PPI and DPI

Both of these are ways to measure resolution. PPI means ‘pixels per inch’. Cameras and monitors measure in PPI. DPI means ‘dots per inch’, and printers measure this. Printers convert pixels into dots of ink to be transferred to paper. The number of pixels or dots per inch will dictate how large a photo will be printed—a certain number of total pixels, at a certain number of pixels per inch, will result in a print of a certain size. Increasing the PICTURE’s dimensions without increasing the resolution, however, will result in a pixelated image.

Images displayed on a computer screen only need a very low resolution to appear acceptably detailed.

Photos can be resampled – have pixels added or taken away as the dimensions are changed – in Photoshop or another image editing software. Increasing resolution this way, however, isn’t as useful as having a high resolution in the first place, because the added pixels contain no new data. The program merely guesses as to what they should be, based on the rest of the picture. If a high resolution is needed (e.g. the picture will be printed large), it is always best to start with a high-resolution image.

MEGAPIXELS

The resolution of a camera’s display monitor is usually expressed in megapixels. 1 megapixel=1,000,000 pixels. Camera companies often round up the decimal point of the megapixel count to make it appear as if there are more pixels then there actually are. The number of total pixels is also misleading, as some pixels are used not to capture and display information, but to process it, when a picture is taken, and therefore are not seen. Measure how many pixels a camera is capable of displaying within a picture.