Coloring on the basis of filed in not possible in Qlik Sense until now. you can set color by range or value of any field but not as field one is red and second is green.
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Thanks for adding your inputs but point here is , you can specify any certain color n fields , yes choosing color by dimension gives a unique color to fields but you can set it by your own use case. What we can do only here , we can create condition like for Year Filed , 2012 will be red and 2013 will be green for example but now as amount will be red and quantity will be green.