Conversion of hypo into hypo solution treated as manufacture, hypo solution classed as a separate manufactured photographic fixing bath. Conversion of 'hypo' into a 'hypo bath' (hypo solution) constitutes manufacture because the fixing solution is a specially formulated product containing hypo plus additional chemicals (hardeners, bisulfite, buffers, boric acid) and is therefore different from raw 'hypo'. The hypo bath is classifiable as a separate manufactured photographic fixing bath under Heading No.37.07, while 'hypo' in retail ready measured doses also falls under Heading No.37.07; otherwise raw hypo is classifiable under Heading No.28.32 as thiosulphates.