Digital imagery firm Scientific Digital Imaging posted a first half pre-tax loss after the economic climate produced an unexpected shift in product mix but it expects new products released in the second half to substantially boost earnings.The group, which develops software that makes it easier to see microscopic images, reported a pre-tax loss of £186,000 for the six months ended 31 October 2010 compared to a profit of £43,000 the year before. Revenue for the period rose to £3.5m from £3.4m the year earlier. Commenting on the group's performance chairman Harry Tee said, "Our expectations of a stable market were proven relatively valid; however the economic circumstances have resulted in an unexpected shift in product mix, resulting in an increase in the proportion of lower margin instruments and consequently a reduction in gross percentage margin." SDI is planning new product lines within Synoptics and Atik, which the board expects will 'contribute to a substantially stronger second half'."The group's strategy will result in good medium-term growth and in an improvement in our margins over the balance of the financial year, particularly given the strengthening of the supply for some of the growth products."SDI also reiterated its strategy of growth through acquisitions and it expects to complete at least one acquisition in 2011.