What are photographic images made of?
For comparison, let us realize that while digital photos are made up of many pixels, conventional photos are made up of tiny particles called grain. Look at a photograph with a high powered magnifying glass or microscope and you can see the odd shaped crystals that are actually the grain. Each crystal is either black or clear, with some shading of gray. Unlike pixels, which line up neatly, grain follows the image shape more closely. It seems there are grain crystals all arranged neatly in the shape of the image. Thus, on a magnified level, we have resemblance to our picture where on a zoomed in view of a digital photo the apparent image breaks down into a neat grid, called a bitmap, of very obviously square pixels lined up in rows and columns.
With conventional color film, there are three separate layers of emulsion, one for each of the primary colors. In digital, each pixel contains 24 bits of data, 8 each to define the content of the primary colors. When displayed, the single pixel displays as the three color combination. In film, three separate emulsion layers together merge into the required color.
But there is one additional requirement to consider. Both in digital and conventional, the image elements (pixels or grain) must be smaller than the resolution of our eye. We cannot and should not see them for if we did, we would not be seeing the apparent image (picture) but either grain or pixels. At this point the system (chemical or digital) fails. So we have our main objective: our photographic system must deliver a particle system that cannot be detected.
For conventional film this really isn't much of a problem, nor has it been for many years. Digital, on the other hand, has always had a problem. CCD sensors have been steadily evolving with more and more sensors on the chip. Quite possibly in the future there will be even higher resolutions available. This will mean more image creating elements and that will equal more detail in our images. Eventually, we may get to a point where the pixels are so small and we have so many of them that we won't worry much about the resolution problem.
Whatever standard we have in the future, we will still have our pixel as the basic image building block. More than likely, there will be many more pixels than we have now as resolutions continue to increase, storage systems get cheaper and computers get faster and more powerful to manipulate larger files. This will allow us to capture more image detail and have greater retouching and editing control in programs like Photoshop. One point will always remain the same, our digital images will still be made of individual pixels. Maybe we will have to dig deeper by zooming in farther but the pixels will still be there.
