In order to design robust image-enhancement techniques for digital prints it is important to understand the fundamental image-quality criteria that provide the basis for satisfactory pictorial print reproduction. Properly established, these criteria are applicable independent of the analog or digital nature of the image, and any enhancement technique should at the least be carried out with an understanding of the before-and-after quality implications. Better still, in the ideal situation the criteria themselves can be used as an integral part of the original design tools during the construction of a systematic rather than an ad hoc set of image-processing techniques.The present study illustrates the use of basic image quality metrics to construct systematic procedures for the enhancement of digital-print sharpness, and for the satisfactory rendering of images covering a wide range of brightness levels. In both cases this offers the possibility of adaptive and continuously-variable enhancement techniques which are both simple in operation and undemanding of computational resources, and some progress in these directions is reported here.