Design for print - Photoshop colour workshop

New doc - resolution 300dpi

Colour mode: CMYK

Considering scale.  If you need to scale up an image consider using a higher resolution ie is you scan a 35mm slide in use 1000dpi so can still get a reasonable print if you enlarge.

                                                 

                                       

                                                                          

                                       

To convert RGB file to CMYK

Menu 

Image 

Mode

CMYK

Always edit in RGB and convert to CMYK at the end. Disadvantage of working in CMYK is that file sizes are larger

RGB are not based on % but a range from 0 - 255

If you use a RGB file can view Gamut warning 

Then adjust image using adjustment - Hue & saturation or Brightness and Contrast

or

Convert file to CMYK to let Photoshop correct

Then adjust image using adjustment - Hue & saturation or Brightness and Contrast

or

Convert file to CMYK to let Photoshop correct

Can layer mask to isolate certain parts of the image then use replace colour.  This provide more control

Increase the fuzziness to select more of the image.  USe the eye dropper to select colour.

Another option (recommended) Photoshop makes the decisions

Menu

View

Proof colours

File appears (RGB/8/CMYK)

This option is where you are still working in RGB but the preview is the CMYK version

Creating colours in Photoshop

Menu

Window 

Swatches

To make a specific pallet

Remove all existing colours

 Delete swatches by holding pointer over Swatches pallet then press alt key.

To make a new swatch

Click on foreground colour

Choose colour

If get ! means not CMYK so click on square below for nearest printable colour

or manually move around until the ! disappears

Add the colour to swatch pallet

Add to swatches or just right click in your swatches pallet

Pick a Spot colour using colour picker

colour libraries

Choose appropriate book for stock or advise from printer

Type a number and will jump to correct colour

To fill can alt delete fill foreground

Always keep ref number

To retain Spot colours in photoshop

Make image grayscale (image, mode)

May need to adjust contrast

Convert to one colour prin job

Image mode

select Duotone

Can leave black or other colour (monotone)

Or use Spot colour click on black square to choose

The black ink is replaced with the process colour

The duotone curve allows you to change how to change how mapped to grayscale ratio

.PSD files support Montone images

If you place in Indesign automatically adds the spot colour to the Swatch Pallet

Can change spot colour and make Duotone or 3/4 colour

Can change the mapping can apply to different parts of the grayscale.

Second method of applying a spot colour

Base on a selection

Channels pallet - how info about colour is stored

RGB = 4 channels

Grayscale = 1 channel

CMYK - 4 channels

Channels can store information about Selections

Select part of the image

then save the selection in the channels 

Ne spot colour

Select area

Channel pallets menu

Select new spot channel

Specify spot clour

Will overprint the black area

When the active channel is selected can use any of the painting tools to edit ie erase etc

Can create a spot channel without using a selection

Select gradient tool to create a tint change solid

Uses for print finishing

Gloss varnish overlay - use a spot colour

Select area wish to apply UV varnish to

Select spot colour 

specify to printer which Pantone colour = varnish