Preparing digital images for print – sizes and formats
Here's a smart guide on how to work with sizes and formats for digital photos and images to make sure they can be reproduced with the right quality in print.
Image size and resolution
The "digital first" publishing approach will sometimes pose challenges for magazines and books since many of today's images aren't primarily made and delivered for print. Define the quality of the photo, illustration, or AI-image, to ensure that it contains enough information to be successfully printed.
1
What is image resolution?
Resolution is the level of detail contained in an image, the number of pixels within that image. The higher the resolution, the more detail and definition the photo will have.
2
What resolution is required for printing an image?
The standard requirement is 300 pixels/inch. If a photo original is delivered in too low a resolution it can become blurry or look pixelated in print.
3
Is it possible to tell from the size of the image data file if the image contains enough information?
No. You can get a rough idea, but it depends on the photo – for example how far the object is from the person taking it. So, it is impossible to say whether 1-2 MB in file size (a common format for an image taken and sent by mobile phone) would be enough. First, see what the photo’s real resolution is, and secondly, use your own eyes to see if the image is clear, the contrast is good and the result is how you want it to be. It also depends on how the photo is to be used. There is a big difference, of course, if the photo is to be printed in the size 1 cm2, or 10 cm2, or something much larger.
4
What difference does the motive make when defining the quality of the image?
Photos containing people and shadows need more prepress work than ones with clear sky and solid colour balloons for instance. Image compression programmes work by finding points with the same colours and simplifying data. If there’s a lot of one colour then it takes up less space – there is less information. So paying extra attention to photos of faces, shadows, and details, is time well-spent. That way you make sure the information is there for the image to be accurately reproduced in detail when printing.
5
Why can't you just change the resolution in Photoshop?
You cannot increase the information on an existing photo just by changing the resolution settings, because then you’re not adding “real” information.
Today, it is possible to enhance the resolution with the help from AI tools or functions in image editing software to a certain extent. As the technology improves even more, it will get easier to “save” poor quality photos and make them fit for use in print.
To make images with the intention of printing them in a large format, using photos in RAW format can help, because they contain much more information. Simply put, photos in RAW capture what the camera actually sees, without any compression or processing of the image data. More image information is stored in a RAW format.
Text by Geoff Mortimore.
Questions answered by Jens Jörgensen, prepress technician, OTW.
Image format overview
Formats for print
When it comes to print, the most common image formats today are .jpg, .tif, .psd or .eps illustrator. Very rarely .png or .svg, which on the other hand are much more common for digital publication.
Vector vs pixel
Pixels are tiny, coloured squares on a screen and when there are a lot of them together, they make up a pixel-based graphic. A vector graphic is a scalable illustration and not restricted to any particular size, so it is good for logotypes and other graphics that need to be scalable.
What is a pixel?
A pixel is the smallest item of information in an image as it can be shown on a screen. Pixels are squares arranged in a two-dimensional grid. The intensity of each pixel is variable; each one generally has three or four colour components.
RAW format
RAW is an image format consisting of minimally altered digital information from a digital camera. RAW is not an abbreviation, it stands for raw, as in unadjusted.
Image format overview
Formats for print
When it comes to print, the most common image formats today are .jpg, .tif, .psd or .eps illustrator. Very rarely .png or .svg, which on the other hand are much more common for digital publication.
Vector vs pixel
Pixels are tiny, coloured squares on a screen and when there are a lot of them together, they make up a pixel-based graphic. A vector graphic is a scalable illustration and not restricted to any particular size, so it is good for logotypes and other graphics that need to be scalable.
What is a pixel?
A pixel is the smallest item of information in an image as it can be shown on a screen. Pixels are squares arranged in a two-dimensional grid. The intensity of each pixel is variable; each one generally has three or four colour components.
RAW format
RAW is an image format consisting of minimally altered digital information from a digital camera. RAW is not an abbreviation, it stands for raw, as in unadjusted.
AI image reproduction in print
Once the image is ready for print reproduction, it's time to handle the colour conversion from RGB to CMYK. In this step an experienced prepress technician may add extra touches to enhance details. Learn more about colour conversion or explore our printed AI-generated images.