When this setting is on, when being send to print, the printer adapts the way it prints to these settings. Instead of the printer printing the colours separately, leaving space for complimentary colours as such, the printer literally overprints the colours to get the overprint colour effect. Below is a photograph of the overprint design featured in the magazine:
This shows the mixing of the four colours of CMYK (Cyan, Magenta, Yellow & Black), the base colours used when printing.
This printing/designing technique only came around in the 1940s when designers have taken to this technique as a device of image construction, around the time when the Swiss International Style started to become known and widely used. Adobe Illustrator is similar to a digital version of old printing techniques, example: The overprinting technique is very similar to the manual printing process, with inks, rollers and different materials like lino. If you were to use this traditional printing technique and to print blue over yellow, or yellow over blue, you would get two different shades of green, as the pigment in the inks would have mixed together. Back in the nineteenth century, the colour mixes were practiced and perfected as overprinting was an important process back then as it meant less colour plates to print, which meant less ink and time spent printing, which then led to lowering the costs of printing.
Below is another design featured in the overprinting article, as an example of how a professional designer (Bradbury Thompson) exploited colour overprinting for production purposes:
In this design, along with the overprinting technique being used, transparency has also been adjusted so that the image underneath shows through a little more. I really like this design as it's a complete mix, showing a detailed drawing with digital elements.
During my final major project, I did experiment with overprinting block colour shapes to try and create a bird. I quite liked this process, as it reminds me of the Swiss International Style, which I'm really fond of. I think I will continue to use this technique more prominently within my work in the future.
References: Eye No. 43 Vol.11 Spring 2002, Pages 36 - 45
