Printing Processes Flashcards
what does RGB stand for?
red green blue
when is RGB colour used ?
- visual displays
- screens
- cameras
- TV’s
what does CMYK stand for?
cyan , magenta, yellow and black
when is CMYK used?
print media [packaging/magazines]
when are spot colours used?
- when the perfect colour cant be made with CMYK
- to cut costs
what does graphics software convert?
converts RGB to CMYK ready for printing
what is the only process where colours are NOT printed separately?
digital printing
what mark checks colour alignment on printed media?
registration marks
what are the 4 printing processes?
- screen printing
- digital printing
- offset lithographic printing
- flexographic printing
properties of screen printing
- can be done at home or industrially
- jigs speed up process [alignment]
- low set up cost
- cleaned and reused
- used on any substrate
how do you prepare a screen?
- coated in photo emulsion
- dried in the dark
- monochrome transparency used to mask areas
- light fixes the photo emulsion to the screen
- excess emulsion washed away
how is a print made in screen printing?
screen laid on substrate and ink forced through it
what tool is used to spread the ink on a screen?
squeegee
how does offset lithography work?
- ink and water added to printing plate
- ink offset onto smooth blanket cylinder
- substrate passes between blanket and impression cylinders
properties and uses of offset lithography
- rapid
- low unit cost
- high quality print
- magazines, books and catalogues
what are the two areas made on lithography plates and what do they do?
- oleophilic image area that ink attracts to
- hydrophilic non-image area that ink repels from
what material is litho printing plate made from?
aluminum
properties of flexographic printing
- fast drying water based inks
- efficient
- cheap
- prints on range of materials, substrates and 3D forms
how does flexography work?
- ink collected from reservoir
- transferred to anilox roller
- doctor blade controls ink volume reaching the printing plate
what type of printing is flexographic and what does it mean?
relief printing [printing from a raised image]
carved wooden block
what are the 2 types of digital printing?
inkjet and laser printing
how do printers operate?
4 colour printing process
ink and toner monochrome or CMYK
properties of digital printing
- digital files sent direct to printer [no plates needed]
- each print customised
- suitable for different substrates
- quality and speed depends on type and printer capabilities
- used for shorter runs
what does laser printing do?
transfers toner electrostatically to the substrate
what does each colour in a printer require?
a separate drum
what charges does the printer have?
drums are positively charged [electrostatic energy]
laser negatively charges drum areas
how does laser printing work?
- positively charged toner powder sticks to negative areas
- transfer belt picks up toner from all 4 drums
- toner deposited onto substrate in 1 operation
how does inkjet printing work?
- ink cartridges act as reservoirs for print head
- printhead passes over substrate from left to right
- tiny translucent ink droplets squeezed each pass
- 6 passes needed for sufficient detail
negatives of digital printing [4]
- use of CMYK means colours not matched accurately
- surface damage common [ink sat on surface]
- expensive for large volume runs
- few compatible substrates
positives of digital printing
- fast lead time
- customizable
- easy to use
