What is a high resolution image?Thursday, 1 November 2012
|An original high res image - note the clarity and clean lines|
|A low res, compressed image - note the blurriness and pixelation when it's set in too large a size|
When newspapers or magazines print a picture, it needs to be of the highest resolution possible. If you've ever had a journalist request images, or designed something for print, you will probably have been asked for some.
But what is high resolution? In short, it means a big image. The size of an image needs to be big, so it comes across clearly in print, with no little squares (pixellation) or blurring.
When you take a picture with a digital camera, usually the automatic setting size is around 2mb. This is ideal for print. The minimum size that can be used is 1mb (though 2mb minimum is ideal)
When images go online, a lesser quality is needed. If you or a web designer has put photographs on your website, they have usually been reduced in size, so they don't take too long to load.
These pictures cannot be used in print. They seem fine when viewed on a screen, but if they are printed the image will be pixelated and of poor quality.
You can see what resolution a picture is by viewing the properties. Right click on an image in a folder, or when it's opened, and click 'Properties' on the menu. This will tell you what the size is. If it is less than 1mb, eg 70kb, then it has been reduced for the web and will not work in print.
You can also hover your mouse over the image, while you are viewing the thumbnail in your folders (eg My Pictures). You will see the image size after a second or two.
Additionally, when you attach an image to an email, the size will be displayed.
If you do not have the original image, then a reduced one cannot be used. Once an image is compressed, it cannot be returned to it's original format. In short - a picture can be compressed, but cannot be increased in size.
If you ever need to reduce the size of an image, it is always a good idea to keep a copy of the original.
So, what if you don't have the high resolution images on your files? Unfortunately, there's not a whole lot you can do about it. But think back - have you used those images in a brochure? If so, you would have given the high resolution images to a graphic designer. Ask them if they still have them on file.
If not - then you can't use those images for print.
Have any questions? Let me know in the comments!