Resolution is a commonly used term in the printing world. Problems with image resolution are some of the most common issues printers encounter. But what is resolution and why does it matter to you? Knowing some basics about resolution will save you time and give you the high quality results you’re looking to achieve.
Resolution, in simple terms, is the level of detail in an image. This can be looked at in terms of screen or web resolution and print resolution. Web resolution is measured in pixels per inch (PPI) because screens use electronic pixels, or square units of color, to build an image. This type of resolution is typically given in measurements of width x height, such as 1920 x 1080 (a typical monitor resolution). The pixels per inch for a web image is typically 72 PPI.
We’ve all seen a pixelated image printed. The boxy and blurry image is a definite sign of low resolution and looks unprofessional. Because lower resolution images (remember, 72 PPI) contain less detail, they take up less storage space and load quicker on a display screen. However, less detail yields poor printed results.
Printing presses apply dots of ink onto paper to create text and images. Print resolution is a measure of how many dots per inch (DPI) are printed to make up the image. The more dots of ink that are printed per inch, the higher the resolution of the image and the sharper the image will be in terms of detail. Most digital and offset printing presses print at a resolution of 300 DPI, which is considered high resolution and the minimum DPI for quality printed output.
Since the high resolution (or hi-res) artwork files used for printing are created with graphics software, they originally exist in pixel form. So how do we translate pixels into dots? Prior to press output, sophisticated graphics software converts the color information of each pixel into the various dots needed to recreate the artwork onto the printed piece. The settings within the document file will determine how many dots per inch are needed, based on the pixels available.
How to Ensure High Resolution
This discussion is getting pretty technical; it can be a lot to take in. The most important thing to remember is that you need to begin with a high quality image at the highest resolution and image dimensions you can get. In this case, bigger is better! You can always go down in size, but you cannot enlarge an image without losing quality.
You’ll need different resolutions depending on the size of the printed image, where it will be displayed, and how it will be printed. For example, a sign in Times Square can be printed with a lower DPI than a brochure because the viewing distance is farther. (The idea of viewing distance can lead us down a rabbit hole of information… if you’re interested, check out this chart.)
In Photoshop, you can go to Image > Image Size to see the dimensions of your image. You’ll see the dimensions listed in pixels, but also the width and height in inches. The resolution measurement shows you pixels per inch. If you want to change the dimensions, you can type in a different width, height, or resolution and see how this affects the other dimensions. You’ll want to make sure the “resample” box is NOT checked because this will alter the resolution of your image.
A final note: Be sure not to confuse image size with file size. Image size means the dimensions of the image (in inches or pixels), and file size means how much space the image takes up on a computer drive (in KB or MB).
Do you have any further questions about resolution and image size? Let your sales consultant know and they can either get the answers you need or connect you with a graphics expert who can help you work through your files.