In our daily life we often neglect such small things, and we never really care to know about them. This is because there are many things which are more important to us are going in our mind. This is usually when you are reading a newspaper you are so focused about the stories it contains that you don’t even wonder why all these newspapers have 4 coloured dots/hearts/squares at the bottom or at the edges. While this information will not harm your habit of reading a newspaper but it is always good to have an extra knowledge of such things.
Those four colours are blue (cyan), pink (magenta), yellow and black also called as CMYK, the base colours for all the coloured used for printing. These four colour can be used to obtain any colour by mixing a correct proportion of them. These four dots are registration marks used during printing to help ensure the print is aligned properly. During printing, they are lined up in the same spot in order to print multi-coloured images with accuracy. If the plates of different colours are not aligned with each other, you will know that the image is not registered properly.
A marker is used check the density of colours and dot formation. Practically it is not possible to check all the pages of the paper, but for a printer who has been doing it for years, very well know what CMYK looks like. If there is anything other than this appears, it will able to identify. So basically they serve as a ‘Printers Marker’. The same methodology is used when printing a book, but while binding them these are being cut out.
So from next time whenever you read a newspaper, the time you see an image is not clear or blurry your eyes will definitely turn to the bottom of the page.