Despite wartime shortages Blacker was able to work in several media, water-colour, oil and ink, the latter used with both brush and pen. She was most successful and prolific in water-colour and in drawing with ink, though some of her pencil drawings show a highly refined and sensitive technique. Her painting with oils on a large scale appears somewhat lacking in subtlety and the pictures look darker and heavier than one would expect from her other work. Her early work as a miniaturist trained her in the delicate touch which a swift flowing medium requires and she never seems to have developed quite the same facility in oils. The lighter media also favour her accuracy of observation and her sure drawing hand.
With the war over Blacker was soon drawn towards recording theatrical subjects with which she had had some contact in the 1930s. Through local connections in Sutton, Surrey, she got to know Dame Lillian Bayliss who had kept the 'Old Vic' theatre open throughout the war and she was acquainted with Dame Sybil Thorndike and others in the acting fraternity.
Determined not to go back to photography as a profession, she set herself up as a working artist making her living by painting a wide variety of subjects. When travel became easier in the mid '50s, Blacker spent an extended period in the United States of America producing many animal portraits. The following year she attended a Vegetarians Conference in India - she was a lifelong vegetarian, not an easy option during the war - and went on to tour extensively in the Far East producing landscapes and numerous portraits.