To make a new colour in Quark, choose colours from the edit menu or the shift key and F12. Then select new from the options. Give your colour a name and select the type of colour from the “model” drop down list, this will usually be CMYK when typesetting a job for print. Uncheck the spot colour option and then select your colour either by clicking on the colour wheel, using the colour sliders or entering the percentages of colour in the CYMK boxes. Then click OK and your new colour will appear in the colours palette. If you need to make a colour from another document for example a PDF you can always open it in Photoshop and use the colours from the CMYK hex values to get a good match in Quark.
