Another issue is that the eye is most sensitive to hue differences, then chroma and finally lightness and dE76 does not take this into account (since Lab does not take this into account). Conversely, the same amount of color shift might result in different dE76 values. So different amounts of visual color shift in different color areas of Lab might have the same dE76 number. One problem with dE76 is that Lab itself is not 'perceptually uniform' as its creators had intended. It is also known as dE-Lab and dE-ab (although I'm REALLY not fond of dE-ab as it implies that only the a* and b* color components are calculated and L* is left out) If you hear people speak of just plain 'delta-E' they are probably referring to dE76. If you can imagine attaching a string to a color point in 3D Lab space, dE76 describes the sphere that is described by all the possible directions you could pull the string. The L*a*b* colorspace was devised in 1976 (let's just call it Lab for short) and, at the same time delta-E 1976 (dE76) came into being. So, a bit of history is probably in order. removes subjectivity (as much as possible).how effective is a particular profile for printing or proofing.how far off is a print or proof from the original.After all, we've spent the money on the instruments, shouldn't we get numbers from them? Delta-E numbers can be used for: It's perfectly understandable that we would want to have a system to show errors. Also, the same dE color difference between two yellows and two blues may not look like the same difference to the eye and there are other places where it can fall down. Some color differences greater than 1 are perfectly acceptable, maybe even unnoticeable. Unfortunately - and probably not surprisingly - it's not that simple. So any dE less than 1.0 is imperceptible (as in turn the lights off and head to the pub) and it stands to reason that any dE greater than 1.0 is noticeable (as in put the coffee on, we're going to be here a while). The idea is that a dE of 1.0 is the smallest color difference the human eye can see. As with many things color, it seems simple to understand at first, yet the closer you look, the more elusive it gets.ĭelta-E (dE) is a single number that represents the 'distance' between two colors. You don't have to spend too long in the color management world before you come across the term Delta-E. 1.7 Choosing the right tolerance (Billmeyer 1970 / 1979).1.6 Finally, which equation should be chosen and how should it be used?.1.5 A few important points about delta-E calculations in general.

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