Colour Separation The foundation of all printing processes …………… GCSE GP Exam Zone AS GP Run Slideshow Run Slideshow  A* 100%

The Basic Principle for all printing processes images are separated into 4 colours Cyan, Magenta, Yellow and blacK(ey) (CMYK) for all printing processes images are separated into 4 colours Cyan, Magenta, Yellow and blacK(ey) (CMYK) an image is produced by printing each colour separately one on top of another. As the inks are translucent they mix to produce a wide range of colours and tones. an image is produced by printing each colour separately one on top of another. As the inks are translucent they mix to produce a wide range of colours and tones. Offset Lithography/Four Colour Printing Process/four process colours

Quality Control What can go wrong during printing? Colours not the right density Colours not the right density Colours not the right density Colours not the right density Colours not aligned Colours not aligned

Colour Bars colour bars are printed alongside so that the thickness and density of each colour can be measured to ensure that it is correct colour bars are printed alongside so that the thickness and density of each colour can be measured to ensure that it is correct Offset Lithography/Four Colour Printing Process/Print Register and Colour Density) both greyscale and both greyscale and colours are monitored photo from base of a cereal box a densiometer is used to measure ink density a densiometer is used to measure ink density

Registration 4 registration marks are printed in the corners of every sheet to ensure that all the colours line up exactly 4 registration marks are printed in the corners of every sheet to ensure that all the colours line up exactly Offset Lithography/Four Colour Printing Process/Print Register and Colour Density) if the colours do not line up then blurring occurs if the colours do not line up then blurring occurs

Bleed Mark 4 crop marks are printed in the corners of every sheet to show where the sheet must be die cut 4 crop marks are printed in the corners of every sheet to show where the sheet must be die cut bleed marks show when the inks are too liquid and bleed into other areas bleed marks show when the inks are too liquid and bleed into other areas Crop Mark

registration mark grey scale colour bar crop mark colour bar bleed mark

GCSE Exam Zone 2007-Q2(e)(i)+(ii) 2003-Q1(e) 2008-Q1(d)

The drawing opposite shows one of the question cards used in the board game. The question card is printed in full colour. Quality control checks are carried out at important stages during the manufacture of the question card. Name two important quality control checks that should be made during the manufacture of the question card. 1. ……………………………………………………………………………………………….…………………...… (1) colour density (1)2008-Q1(d) 2. ……………………………………………………………………………………………….…………………...… (1) registration (1) size of card (1) physical properties of the card: surface finish/colour/weight (1) RETURN

When packages are printed in shades of grey, a control strip is often printed on the package. A control strip is shown opposite. (i)State what the control strip is used to measure. ……………………………………………………………………………………………….…………………...… (1) (ii)Some packages are printed in full colour. When printing in full colour it is important that the image-register is correct. Describe one way to achieve correct image-registration …………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………….… (2) greyscale colour density (1) registration marks (1) are used to align the four colours (1)2007-Q2(e)(i)+(ii) RETURN

The full colour printing on the packaging has to be checked for quality before it is used for the final product. Explain two methods of quality control used during a full colour print run. 1. ………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………….…………………..… (2) registration marks (1) are used to align the four colours so that the printing is not blurred (1) RETURN 2. ………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………….…………………..… (2) colour bars (1) are used to check the density of all the colours so that they are correct (1) greyscale bars (1) are used to check the density of all the greys, black and white so that they are all etc are correct (1)2003-Q1(e)

AS Exam Zone 2007-Q2(e)(i)+(ii) 2003-Q1(e) 2008-Q1(d)