Understanding Resolution in Digital Photography

When you are entering the world of digital photography, resolution is a common term. This topic can be confusing as each item in a photographic chain has a different relative resolution value. They are not interchangeable. Once you know what you are measuring, you can plan accordingly.

Camera and Image Resolution

The millions of pixels that make up a digital camera’s image sensor are actually small light-sensitive squares. When you click on a photograph, each pixel records the brightness of the light hitting it. A digital image cannot identify the pixels within a photo unless it is magnified. You can magnify an image to see that it is a web of interconnected lines, known as rows or columns. These lines form small boxes or squares with colored colors. These boxes are called pixels. The camera’s ability classify and effectively present distinct image information such as patterns and textures in a photographic image. Resolution refers to the size of a photo without making it unacceptably blurry.

Measurement of the Resolution

The resolution of a digital image

The measurement of pixels in height and width can help identify resolution. A camera manufacturer might describe the resolution as 3904×2598 pixels (W x H), which can again be referred to as 3904×2598=10.142.592 pixels. This number can be divided by 1,000,000 to get 10.1 megapixels. One megapixel equals one million pixels. The resolution of an image can be described as 10.1 MP or 10.1 megapixels.

Image Resolution Printout Guide

Image resolution printout guide

Here’s the Rule of Thumb: The more pixels an image has, the more information is contained within it. Therefore, the resolution should be higher. A higher resolution image will contain more detail and allow for larger prints with consistent tone and color accuracy.

Scanner Resolution

Scanner Ressolution

The scanner is the crucial link between digital and non-digital formats. A scanner can convert any analog image into digital format. How sharp will that image be? The resolution of a scanner is measured using a pair number, such as 300×300, 600×600, or 2400×4800. This is the resolution of the scanner moving horizontally or vertically over an item (such as a slide, photo print, etc.) during conversion to digital. Higher ppi means that more information is captured at the pixels level. This gives your photo greater detail, sharpness and color accuracy. The scanned image can be edited, manipulated, and altered in a much more intuitive way than if it were scanned manually. When you transfer an analog image to the digital space, it’s likely that you will need to “clean up”. You can also make larger prints with a higher scanning resolution. For scanning photo prints at original size, you will need at least 300 ppi. 600 ppi is recommended.

Monitor Resolution

Monitor Resolution

Computer monitors are diagonally measured to inches. The image on a computer monitor’s diagonal is measured in inches. The screen resolution is the total number of pixels that can simultaneously be displayed on the screen. This resolution is usually described using a pair of numbers such as 2560×1440. The computer screen measures 2560 pixels in width and 1440 inches tall. Other sizes that are popular include 800×600 (SVGA), 1024×768 (XGA), 1280×1024 (SXGA), 1280×1024 (SXGA), 1600×1200 (UXGA). The resolution of the monitor and the size of the image will determine the actual number of pixels per inch. A monitor can display an image with the same number pixels, but the size of the screen will affect the actual number of pixels. Larger screens have more pixels, so the number of pixels on the larger screen may vary. A color display has one pixel. It is actually a combination between three colors, red, green and blue. These tiny elements that form an image on a monitor are called pixels. The resolution of a monitor is measured in Pixels per Inch (or PPI).

Printer Resolution

Printer Resolution

Your printer resolution is the printer’s ability of laying down enough color or black ink for your digital image to reproduce it accurately and smoothly. The Dots per Inch (or DPI) measure the resolution. A laser desktop printer can print at 600 ppi. Inkjet printers may have a higher resolution, up to 2400 dpi. Inkjets can be used to print photographic images because of their high resolution. They are able to reproduce colors accurately, highlight and shadow detail, as well as the overall image detail. You can print with inkjet printers up to 4-10 colors. For a smoother, more consistent Black reproduction, you can use multiple Black inks. A higher dpi printer will not improve the quality of your images. This is only possible if your original image file contains more pixels. You can’t increase the resolution of an image by printing at high dpi. This will result in a photo that has pixels that are larger than it is. The printed image will look unpleasant. If you want sharp prints of good quality, your image should have a lot of pixels.

Conclusion

Digital photography resolution is often misunderstood because each piece measures it differently, so the “value” of each piece is not cross compatible. It is important to know how each piece of equipment measures resolution so you can get the best possible picture for your end-product. A 12 megapixel camera will not be sufficient for images that will be shared on social networks. A 300 dpi printer may not be sufficient if you want to print Fine Art quality photos. It’s not safe to spend as much as you can afford on resolution. You might never use it, and your money could be better spent elsewhere, like on a better lens.