Color film prints can only show a small fraction of the information available on a video monitor. Color ink-jet printers are worst of all. Relatively speaking, they can't do much. Light passes through the ink, reflects off the paper and passes again through the ink on its way to our eyes. This imposes a significant color penalty.
Slide film has a high resolution and is sensitive to a very wide range of colors.
Your eyes will get enough information from a slide that you will see a nice picture. On the other hand, a color ink-jet printer can't print such a wide range of colors, can't print such fine variations of color, and has a terribly low resolution compared with a color print or slide. The resulting image simply doesn't have enough information in it for your eye to pick anything out. If it doesn't, you should investigate your scanner. Let's say you have an image that looks good on a monitor.