Creative Strategy: Digital Colours to Print 4 - Notes

To create separate positives from channels in Photoshop click on the channels menu then its option selection before selecting split channels. The file then will open into layers. From here you'll need to halftone the files.

Only print halftones with inkjet printers/

Only downside really is having to save each document for each positive.

Angles 15, 75, 105, 155

How to create positives from a merged file -

Select colour range

Select area of colour for channel

Channels menu - create new spot channel

Play with levels to remove different shades/colours

Go back to original image (hide new spot channel)

Repeat for different shade/colour.

Black channel would already exist from CMYK channels.

Duplicate black

Double click new image

Change to spot colour

Make black by selectinf K100% in colour picker

Change solidity to 100%

Change name to Spot Black or something similar.

Next layer

Hide new channels and make sure CMYK layers are not hidden

Colour Range

Select area

Select

Modify Expand - this will feather the selection out a bit (try 3 pixels minimum)

This is called trapping as it will minimise mis-registration of prints when screen printing due to overlap)

Channels

New Spot Colour

Finally place channels in order of print (black on bottom - then up).

Photoshop -

For a layer with transparency press CMD and hover over layer. Then click - it'll select the entire visible layer.

Create new spot channel.