set layers to multiply so you can se more accurately what the print would look like
overprinting allows new colours to be created as they overlap
knocking out removes the chance of overprinting as areas are deleted so they cannot overlap
Knocking out
select area with magic wand tool in other layer and delete
Halftone in Illustrator
before in photoshop, image> mode > grayscale
you may then need to adjust brightness/ contrast
save as a tif file
In illustrator, print> output> mode: seperations
frequency 50
angle 15
measured in lines per inch (50lpi max)
angle 15 (for one ink) to avoid Moire Pattern:
laserprint from upstairs computer room
202 b&w printer
Halftone- Bitmap in Photoshop
Can use this technique to apply halftone
image> mode> output: 1200
Method> Halftone screen
50
15
save as tif
take to digital print resource to print
Colour
CMYK colour mode is used for print, it allows us to create a wide variety of colour through overprinting
can see this in photoshop under channels
in illustrator, print> mode: seperations
can now set half tone values for each inks
frequency: 50
angles (for four inks): 15, 75, 105, 155
Spot Colours
One spot colour is used to print a colour e.g use green ink as opposed to mixing colours yellow and cyan to get green.
- Spot colours allow accurate reproduction of colour e.g Sainsbury's logo
- It can be cheaper- fewer inks makes production less expensive
- Spot inks are used to print colours that are not reproducible using CMYK- fluorescent and metallic inks for example
In photoshop we can simulate spot colours, make sure your image is in grayscale...
channels menu> new spot channel
change solidity to challenge transparency:
the order of channels is important, the top will be printed first, bottom last.
Save as Photoshop or TIF file, make sure it's ticked spot colours
Then print in Illustrator, remembering to separate spot colours and turn off CMYK
only change values if a certain layer has different tones (50 max):
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