OUGD505 - Preparing for Commercial Print 1 & 2

OUGD505 

Preparing for Commercial Print 1 & 2

Notes:

Screen printing
Adjustments - threshold (no shades of grey)
Hue/saturation layer is used to visualise the colour of the print. Colourise optional.

Down pointing arrow next to adjustment layer effects everything below it.
Right click - clipping mask - Isolates to only effect the layer directly below.

Printing ink has a transparency. The multiply blend mode simulates this.

Knocking out
Select layer - magic wand - go to background layer - delete

Halftone
Frequency is measured in lines per inch. 50 lines per inch max.
Angle - for one ink is 15 degrees
To avoid moire patterns (optical interference)

Inkjet = Bitmap (large format in the digital print resource)
Bitmap = Mode - Bitmap (must be a grey scale image)
Resolution = 1200 ppi
method - halftone screen

Screen print CMYK
Angles 15, 75, 105, 155 degrees

Spot colour
Photoshop - fore ground colour - colour picker - colour libraries.
Solidity of inks can be changed.
make greyscale
channels - channels menu - new spot colour
Channel spot colour only supported as psd. of Tiff.

Duotone
Image - mode - duotone
only available on grayscale images

Spot colour in illustrator
Swatch menu - open swatch library - colour books

Delete existing colours
add used colours
If using spot ink, change from process to spot.

View Separations on Illustrator
Window - Separation preview - tick overprint preview

Spot colours automatically knock out on illustrator

Positives based on colours rather than shapes

Overprinting on Illustrator
Window - attributes
Object specific option
Only see the result of overprinting is separation preview is turned on

Spot colour can be applied in Illustrator to a greyscale document prepared in Photoshop
Window - links - menu - Edit original 
Set blacks to over print if on top layer.