 Developing lossy compression techniques as closely matched to human perception as possible is a complex task.Sometimes the ideal is a file that provides exactly the same perception as the original, with as much digital information as possible removed; other times, perceptible loss of quality is considered a valid trade-off for the reduced data.The terms 'irreversible' and 'reversible' are preferred over 'lossy' and 'lossless' respectively for some applications, such as medical image compression, to circumvent the negative implications of 'loss'.