A resolution to bad image quality

For individuals new to print, image resolution may not be at the top of mind when submitting files for a high quality print. That’s a shame because the back and forth created to get your printing partner a high enough resolution image can sometimes be challenging (if there’s even an alternative you can use). And worse yet, the revision dollars can quickly add up, and your turn time suffers from the added time to create a quality print.

So, what is a good resolution for your image? Our raster image processor (or RIP) is setup to flag any images that fall below 150 dots per inch (or DPI), but we recommend that ALL your photos be at a minimum of 300 dpi at the size you wish it to be printed. Below you can visually see the differences between image resolutions we commonly see, and as you might notice – while 72 dpi might be good enough for the internet, it’s not the best choice for a printed piece.

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From left to right: 72 dpi, 150 dpi, 300 dpi

There are also different file types that you can use to ensure your logos and graphic elements also have the crisp lines you’re after.

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Raster: Raster images are your typical .JPG, .BMP, .PNG and .TIF formats that utilize a dot matrix format that generally represents a rectangular grid of pixels, or square points of color. Think photographic images. Typically speaking, these pixels are small enough that the image looks crisp, but when you enlarge the viewing pane in which you are seeing the image, the square points of color become much more noticeable.

This is why it is critical to ensure that your image resolution is 300 dpi at the final size you wish for it to be printed. If an image is 300 dpi at 3″ x 3″, but you wish to enlarge it to fill an 8″ x 8″ sheet, your image quality will suffer.

Vector: Vector images use points, lines, curves and shapes to represent images. Based off of vectors, or paths and strokes, each line leads through a control point. Each of these control points have a specific X and Y value and helps to define the direction of the paths track. Unlike raster images, vector images can be enlarged infinitely without losing the quality of the image itself. Common vector formats are .EPS, .AI and .SVG files.

ScreenShot100Not sure how to check the resolution of your image? Inside Photoshop you can quickly access this information by selecting “Image Size” from the “Image” menu at the top. The screen that displays allows you to double check your resolution.

If you’re inside InDesign and have just placed a photo, selecting the image and viewing your “Info” window will let you know the current resolution of the image at the size you have it scaled to. Ensure that the “effective” pixels per inch (or ppi) is 300 or greater when outputting your final print files.

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2 thoughts on “A resolution to bad image quality

  1. Pingback: The Prepress Checklist | Metropolitan

  2. Pingback: Perfect Binding 101: Tips for designing a perfect bound book | Metropolitan

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