Design 101: Resolution Revelation
That graphic looked great on your screen, but your prints turned out fuzzy. You found the perfect photo for your design using a Google image search, but it seems way too small for your flyer. You just scale it up to the right size, but it looks really grainy. What happened?
Most likely you’ve fallen victim to a misunderstanding of proper resolution practices. What you need is a resolution revelation! Let’s take a few minutes to learn about what “resolution” means and how it plays out in graphic design related applications.
First, let’s define a few terms:
- Pixel: “a single block of illumination on a display screen, one of many from which an image is composed” A computer image is made up of tiny blocks of color called pixels. Generally, the more pixels an image has, the sharper it will be. Though not usually discernible at 100% scale, individual pixels will become quickly visible as you zoom further into an image.
- Resolution: “The degree of detail visible in a photographic or television image” In the realm of computer displays, this degree is measured in pixels. In general, the more pixels and image has, the higher the resolution is.
- PPI: “Pixels Per Inch” This is a measure of pixel density on a screen. PPI is a term used in defining the capabilities of a display screen. The more image pixels a screen can display in a square inch, the higher its PPI rating will be, and the sharper the picture will be.
- DPI: “Dots Per Inch” This is often confused with PPI, but DPI is a term related to the density of ink on a printed page. How many dots of ink are laid down in a square inch? The higher that number, the greater DPI rating a printed image will have, and the sharper the print will be.
The resolution of a screen is measured by counting the number of pixels it can display horizontally and the number of pixels it can display vertically, such as “1280 x 800.” The higher those numbers, the greater the resolution of the monitor is, and the sharper the picture it can display. A monitor with the resolution rating of 1280 x 800 would be capable of displaying 1,280 pixels horizontally and 800 pixels vertically.
Typically a commercial printer will require artwork that is between 300 – 600dpi. Therefore, it is crucial that you create any artwork intended for printing at the proper resolution in order to achieve great results in the final print. While some designers may insist on working at 600 dpi, we’ve found that working at a 300 dpi resolution for print-related designs gives the most flexibility in terms of usable images and file size, and the final printed product is nice and sharp to the naked eye.
Just like a screen display is measured in horizontal and vertical pixels, an image is also measured this way. An image that is specified as 1920 x 1080 would be comprised of 1,920 pixels horizontally and 1,080 pixels vertically. So how can you tell whether an image is going to print nice and sharp, or turn out fuzzy and pixelated? It all has to do with the image resolution. If you are measuring minimum print resolution as 300 dpi, simply divide your image’s horizontal and vertical resolution counts by 300 to determine how large your printed image will be at full printed 300 dpi quality. So, for an image with a native size of 1920 x 1080, the math would look like this: 1,920 / 300 = 6.4 and 1,080 / 300 = 3.6 Therefore, an image that has a resolution of 1920 x 1080 can be printed at a maximum of 6.4 inches wide by 3.6 inches high at 300dpi. If you try to increase the size of the image beyond that, you will run the risk of pixelation or fuzziness in your final print. You can always scale an image down in size with no problem, but scaling an image up beyond its native size will quickly create resolution problems.
So, let’s say you are designing an 8.5 x 11 flyer for printing, and you want to choose a background image for your project. If you want the background to cover from edge to edge, you would be able to determine the minimum pixel resolution for the image by multiplying the width and height by 300 (print resolution). So, the math would look like this: 8.5 x 300 = 2,550 and 11 x 300 = 3,300 Therefore, your background image would need to be a minimum of 3300 x 2550 pixels in order to print on an 8.5 x11 at full resolution.
So how do you determine the size and resolution of an image? If you have Adobe Photoshop, open the image and choose “Image > Image Size” from the menu. This will show you both the image size and resolution. You can choose to see the height in width in pixels, inches, or a number of other units of measurement.
If you don’t have Photoshop, you can still get most of this information right from your Mac or Windows operating system. On a Mac, simply right-click your image in Finder, and choose “Get Info.” This will display the image size in pixels. On a PC, right-click the image in Windows Explorer and choose “Open With,” then choose “Paint.” Once the image is open in Paint, choose “File > Properties” from the menu. This will show you both the image size and resolution.
ProChurch Power tip
While there is no magic way to increase an image’s resolution beyond it’s native size with pixel-perfect results, there are several software programs that do a great job at using algorithms to guess the best way to add additional pixels to an image to create the illusion of higher resolution. One of the best available is called “BlowUp” by Alien Skin Software (http://www.alienskin.com/blowup/). This program does amazing image enlargements and is a “must-have” for situations where there are no other options but to use that photo.