Advanced positives

Positives - screenpriniting

Desaturate - b&w

Multiply (over printing)

Or selection and deleting (knocking out) 

Turn off hue and sat= positive 

Variation of tone printed = half tone,

Frequency= meausired in lines per inch (50) 

Angle (avoid Moire) - for on wink = 15 degree

Halftone - grayscale,

A3 or smaller- save as tiff, in illustrator- print- use black and white- output- change mode to seperations- no frequency higher than 50, angle of 15 on the black 

Larger than A3: bitmap, set resolution to 1200, use halftone method, nothing more than 50 freq, angle of 15 degree

Colour seperations 

CYMK= print

Rgb=digital

Make sure image is cymk, channels, 
In illustrator again - output- separations
For four inks- 15, 75, 105, 155 angle
 For larger images than A3- split channels and one image for black, yellow etc and apply bitmap process

Spot ink- Pantone colour reference system, colours like fluroscents 
Use spot colour for screen print 

Spot ink:
Grey scale image on photoshop- new spot channel on the settings, choose colour to represent ink, more spot channels sees the overlay of the colours, select and delete if want to 'knock out', double click thumbnail to change the colour of the spot channel- seeing how it works with different colours, the order equals the order to screen print in
Either tiff or photoshop to have the spot colours checked 
Open in illustrator - untick the cymk, only change frequency of used tints of colours - set to 50