A method of driving a passive matrix electroluminescent display (120, 322) using multi-line addressing to display an image, the method comprising: inputting image data for said image; determining, using said image data, a first set of image subframe data for a first plurality of image subframes each representing a common spatial portion of said image, wherein said first plurality of image subframes combine to approximate said common spatial portion of said image; driving said display (120, 322)using said first set of image subframe data; determining, using said image data, a second set of image subframe data for a second plurality of image subframes each representing said common spatial portion of said image, wherein said second plurality of image subframes combine to approximate said common spatial portion of said image; and driving said display (120, 322)using said second set of image subframe data, wherein said image data defines a target image matrix, and wherein each of said determining of said first set of image subframe data and said determining of said second set of image subframe data comprises factorising said target matrix to determine first and second factor matrices defining data for respective first and second axes of said display (120, 322), each of said first set of image subframe data and said second set of image subframe data defining data for a plurality of said subframes, said target matrix substantially a product of at least said first and second factor matrices (R,C), wherein said factorising comprises non-negative matrix factorisation, wherein, for each of said determining of said first set of image subframe data and said determining of said second set of image subframe data, the determining of the set of image subframe data comprises iteratively determining the first and second factor matrices of the image subframe data from initial value data of the first and second factor matrices (R,C), the iterative determining comprising for each subframe of the set of image subframe data an iteration determining a said first and second factor matrices (R,C), each said iteration using the determined first and second factor matrices (R,C) of a preceding said iteration such that an error between the target matrix and a result of combining the subframes of the set of image subframe data converges towards zero; and wherein said initial value data comprises initial said first and second factor matrices (R,C) initialised using said image data and is different for said determining of said first and second sets of subframe data. inputting image data for said image; determining, using said image data, a first set of image subframe data for a first plurality of image subframes each representing a common spatial portion of said image, wherein said first plurality of image subframes combine to approximate said common spatial portion of said image; driving said display (120, 322)using said first set of image subframe data; determining, using said image data, a second set of image subframe data for a second plurality of image subframes each representing said common spatial portion of said image, wherein said second plurality of image subframes combine to approximate said common spatial portion of said image; and driving said display (120, 322)using said second set of image subframe data, wherein said image data defines a target image matrix, and wherein each of said determining of said first set of image subframe data and said determining of said second set of image subframe data comprises factorising said target matrix to determine first and second factor matrices defining data for respective first and second axes of said display (120, 322), each of said first set of image subframe data and said second set of image subframe data defining data for a plurality of said subframes, said target matrix substantially a product of at least said first and second factor matrices (R,C), wherein said factorising comprises non-negative matrix factorisation, wherein, for each of said determining of said first set of image subframe data and said determining of said second set of image subframe data, the determining of the set of image subframe data comprises iteratively determining the first and second factor matrices of the image subframe data from initial value data of the first and second factor matrices (R,C), the iterative determining comprising for each subframe of the set of image subframe data an iteration determining a said first and second factor matrices (R,C), each said iteration using the determined first and second factor matrices (R,C) of a preceding said iteration such that an error between the target matrix and a result of combining the subframes of the set of image subframe data converges towards zero; and wherein said initial value data comprises initial said first and second factor matrices (R,C) initialised using said image data and is different for said determining of said first and second sets of subframe data.