Creative Suite Session2.

Photoshop
every image that you work on in photoshop has a colour mode but RGB and CMYK are the most common. The default mode for a photoshop image is always RGB. 
The RGB colour mode has many more colour options than CMYK, and so when converting between RGB and CMYK, some of the colours may be changed to the next closest colour.

 On an RGB colour photograph, you can use the gamut warning on the view menu to show which colours lie outside the CMYK colour range. 

The saturation and brightness of an image has a lot to do with the colours being outside the CMYK colour range, and so adjusting these can quickly fix the image. 

Selecting proof colours in view, this lets you work in RGB mode, but shows you how the image will look when you convert to CMYK colour, and so this will show you exactly how the image will look when it is printed. 

To pick a colour and add it to swatches in photoshop you have to double click on the foreground colour and choose the colour, then add to swatches. The box with the exclamation mark above it shows that the colour chosen is not within the CMYK colour range and so by selecting on that colour it will choose the colour closest to the one you have selected.

To use spot colours in photoshop we need to be able to show the specific pantone code within the image

Creating a duo tone image
The original image has to be greyscale, then from the mode menu, choose duo tone.

 

By using duo tone we can choose spot colours for the image, up to 4, and also change the curves to adjust the colours. 

 

 

 

Another way to use spot colours in photoshop is to use channels in the sidebar, and with these you can choose a new spot channel where the colour can be chosen and then shapes drawn over the image or text.

With the channels you can also select an area and then apply a spot channel over the top of that and so only that area will be coloured.
The solidity of the spot channel affects the transparency of the colour, although this only really changes its appearance in photoshop.