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Grayscales and Halftones
Posted by Karl | Posted in Color | Posted on 27-12-2011
In the last post we started discussing color and the different ways in which it can be used but we also touched on some terminology such as grayscales and halftones which we shall clarify here for you today.
A black and white photograph is probably the best example we can give you of what a grayscale actually is – the picture is made up of differing shades of gray between black and white and the differences create the picture reproduction you actually hold in your hand.
The grayscale has an absolute black, an absolute white and between there are 254 differing shades of gray – this is 256 “colors” in total or in computer tekkie parlance is 8-bits of information.
An image is only grayscale if it is made up of differing shades of gray; another way to make an image is using absolute black and white lines to create the effect of differing shades making up the image – in this case it is known as a bitmap and not a grayscale.
The difference is important when it comes to the printing process because you can scan an image as grayscale or bitmap – scanning a grayscale image as a bitmap will render all the information contained within it that is no absolute black or white meaningless i.e. not reproduced and you lose the detail. Perform this in reverse and you get a blurred image i.e. scan a bitmap image using grayscale.
Screens and Halftones
A screen is what is applied to a photographic image which gives the impression another color has been used or is present when it was not at the time the photo was taken.
Using screens or halftones, you can convey a lighter image effect or a change in the color tone itself and they come in a wide variety of strengths so you can play around with your final image result and all you are using is one ink which reduces the cost to you with your final product.
Herein lies the key – using a lower number of inks allows for cheaper cost and this is where screens come in handy for you as the buyer as well as helping create a better image for the reader and enduser.

