Print Resolution is simply the level of detail in a printed image. Higher resolution means higher detail, and can be measured in dots per inch (DPI). The more dots (of ink) that are printed per inch, the higher the resolution of the image – therefore the higher the quality in terms of sharpness and detail. When it comes to printing, resolution is super important, as a high-quality image looks beautiful and professional, whereas a low-resolution image looks fuzzy, indistinct and completely unprofessional.
When you’re creating your source image (the image you want to be printed), make sure it has a suitable resolution. A general rule: the higher the resolution, the better the image. You can always scale down in size, but never scale up; at least not without losing quality. Make sure your image has the highest resolution and image dimensions you can get. The only consideration is that you’ll need different resolutions depending on how large the printed image will be, where it will be displayed, and how it will be printed. For example, an enormous billboard can be printed with a lower DPI than a small leaflet, even though it’s larger in size. One of the most common problems faced by printing companies, is clients uploading digital files with a resolution that is too low to print. When it comes to source images, bigger is always better.
Print resolution can get very technical very quickly, and sometimes it feels like it’s not worth getting in to. But it is. To help you navigate the confusing world of print resolution, ChilliPrinting are here to offer you some hot tips.
Choosing your Resolution
The golden resolution is 300DPI. This is the perfect resolution for all printing materials, and since 354DPI is the maximum resolution an offset printing machine can handle, anything beyond that will only increase your digital file size, with no improvement in quality. Anything lower than 300DPI can seriously damage the quality of your image. So always aim for 300. That said, choosing your optimum resolution is all about discerning at what point you can no longer see the pixels in an image. To work this out, you’ll need to consider another important factor: viewing distance.
It doesn’t seem obvious, but viewing distance is a very significant factor in finding your perfect resolution. Many people don’t even take distance into account, but it can actually mean the difference between 300DPI and 3DPI. Whilst printing method and material will affect image quality only slightly, viewing distance affects your required resolution in a number of ways, simply because if you stand further away from an image, the pixels seem smaller.
If you’re designing something that is going to be held in someone’s hand, such as a brochure or flyer, then the optimum DPI is 300DPI. Don’t go below that. If you’re simply printing a photo on your inkjet printer, use 300DPI. If the design will be displayed at a distance (as is the case with posters and billboards), you can get away with less detail. Therefore a poster needs a minimum resolution of about 150DPI, if viewed from 6ft (2m). However, you should never go below 150DPI, as this is the absolute minimum for offset printing, even for big posters.
The further away the viewer, the lower the necessary resolution. But remember, when it comes to DPI: better too high than too low. Lean towards a higher resolution, whilst taking into account how far away the viewer will be. Further equals lower, closer equals higher, but if you can, stick with 300DPI.
Resolution does not mean Size
Resolution is a measure of pixel density, not size. That is to say, a poster measuring 2 x 3 meters could have the same DPI as a business card measuring 2 x 3 inches. Remember it’s dots per inch, so it doesn’t relate to the size of the image, or of the dots. As already discussed, a large image (such as a billboard) can have a really low DPI if it’s going to be displayed very far away (as is usually the case with larger images), as the human eye resolves the image; hence resolution.
Nonetheless, size does have a bearing on resolution. Reducing your resolution by half, would mean you’d need to double the width and height of your printed image, in order to maintain quality. For example, let’s say you’re printing a Flyer measuring 5.5 x 8.5 inches at 300DPI. Reducing the resolution to 150DPI would result in the output of an 11 x 17 inch flyer. So make sure you have the right resolution for the size of your print. If you scale down the resolution, you must scale up size correspondingly.
Digital to Print
Instead of dots (which are round), computers use pixels (which are square). Resolution on a computer is measured in pixels per inch (PPI), which – thankfully – converts directly into DPI. This means a 300PPI digital image will print in 300DPI. Simple, right?
Nonetheless, be very careful… Your source image might look huge on your computer, but still come out low-resolution in print. This is because a digital image that has lots of pixels (for example 3000 x 2000) will look great, but may still have a low DPI (for example 20), meaning it will look terrible when printed at a certain size.
To add to the confusion, your screen resolution will also determine how big the picture appears when viewing it on your computer. The output size (how large it appears onscreen) will seem smaller on a high-performance computer, because it has a higher quality screen resolution. Moreover, monitors use only a fraction of the image’s resolution when they display it. At the standard screen resolution of 1024 x 768, images are displayed at just 0.8 megapixels. By contrast, a professional quality photograph would be printed at 8 – 10 megapixels; this is the standard resolution for printed full pages in magazines.
Hence there are lots of little things that can catch you out when converting from digital to print, but the way to make it work is to ensure that your PPI is the same as the DPI you require. If the digital image is 300PPI, you’re all good. Don’t be fooled by fancy computer screens, or high res digital images with deceptively low PPI.
CMYK or RGB?
These are color schemes. RGB (Red, Green, Blue) is a digital-only color scheme that looks more vivid. However, it cannot be replicated in reality, thus you will always need to print in CMYK (Cyan, Magenta, Yellow, Black). This is because RGB color models are working with a fourth element: background light! On a computer, the integrated light from the screen helps RGB models display a larger spectrum of colors. Unfortunately, paper has no integrated light, so it displays less colors. Choosing between these color schemes won’t affect your resolution, but it will affect the quality of your image, as CMYK tends to look duller and less bold. If you work with CMYK, when making your design in digital, you won’t be disappointed when it comes to print.
As you can see, print resolution can seem complicated, but really it’s very simple. You may need a different resolution depending on what you’re printing, the size, and the distance it will be displayed from the viewer. When in doubt, higher is always better. Go as high as you can. 300 DPI is the golden resolution, and will look great on all your flyers, leaflets, brochures and business cards. Posters can afford to be a little lower in DPI, since they’re generally larger, and viewed from a distance. But if you can make a 300DPI poster, you should. Never go below 150DPI, no matter how large, or how far away your design will be displayed. And finally, don’t let the digital image fool you; when in doubt, contact a designer. They’ll know their way around print resolution like the back of their hand. Be bold, follow our advice, and you’ll be enjoying high-resolution prints in no time.