Depending on what scanning unit your print goes through, a digitized print seldom looks exactly as it does over a light table (which is how the pictures were taken) or when it’s projected. At least, in my experience, it doesn’t. So grading is necessary to get the image closer to how the print looked before scanning. Sometimes the adjustments to color, brightness, and contrast are minor, other times they’re dramatic, but in any case, grading is still needed to some degree, especially if there are inconsistencies in hue/saturation, gamma, and shadow detail across individual shots. For instance, the sample video posted here a year or so back absolutely needed correction, as there was an inordinate green veil over the image that didn’t belong there.