Colour mode
To change the colour mode of a file go to
Image> mode
There are colours that you can produce in the RGB mode that cant be reproduced in CMYK mode
Colour Gamut/ range of reproducible colours
RGB gamut it greater than CMYK gamut
RGB is photoshops default colour mode
RGB image
The gamut warning will show if any of the colours are out of the printable range of colours
To manage the colours you can adjust them with:
Hue/saturation
Proof Colours
Colour Swatches
To delete swatches hold
Alt> and click
To save time its a good idea to save an empty swatch pallet
In the swatches drop down menu load up the empty swatch pallet> Replace Swatches
Colour Picker
When choosing colours the little boxes will tell you when colours are out of gamut for print and web
Using Spot Colours
In order to access spot colours it works in the same way as CMYK colour. In the colour picker, click on colour libraries
You can type the pantone colour number for quick selection
A photoshop document can only support one colour mode
Grey scale image
Duo tone image
In order to change an image to duo tone the image has to be a grayscale image
The default setting is monotone
To change the ink you click on the black square
You can chose a spot colour from the colour library
This allows you to change how your new ink maps to the original ink
The diagonal line is an exact mapping to the old ink to the new ink
This allows you adjust the contrast of your printed image
Your not fixed with this setting, it allows you to adjust the spot colour at a later time
Duo tone allows for a second ink to be used
The curves allows you to apply ink to the highlights and shadows etc
There is also a lot of preset option in the drop down menu
When saving a duo tone choose save as
The format you need to save the file as is> PSD
Second way of working with spot colours
Channels
Every photoshop image has channels
A greyscale image has one channel
CMYK has four channels
Each of the channels is a grayscale image
The colour channels give information about the inks that will be used
In the channels drop down menu select new spot channel
To add the colour you simple use the paint brush tool and paint it onto the image
You can press X to switch between foreground/background colour
You can make selection on specific parts of the image for more accurate colouring
Ink are generally transparent
The solidity allows you preview a different transparity of ink
This method works to apply a spot varnish
In the colour picker just name the colour spot varnish
Save files as PSD or TIFF
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