Digital Emulsions MegaVision has been making and selling digital cameras and capture software longer than any other company. In 1987, MegaVision sold the Tessera with Capture Station software which ran on a MegaVision image processing computer known as the 1024 XM. The early days featured anemic computers and Photoshop® 1.0 was yet to be conceived. Without industry reference, MegaVision approached the making of a digital capture application in such a way as to control the making of images for rendering on a reflective substrate. As the pioneer in shooting and processing a digital image for output, MegaVision had to fashion a product and a workflow that would render a workable image. The decision was made not to employ a film scanner interface, which is typically what the modern professional capture interface is patterned after. Nor was the use of a series of triangle shaped sliders to control the image display on a transmissive monitor to replicate the reflective output condition considered. MegaVision understood the printing industry, whose renderings are based on the density range of the paper and ink. When limited by a process that puts 100% ink on paper all of the time, it forces a change to the size of the ink droplet to control density as the human eye sees it. Big dots are darker than small ones. This makes density a very important consideration in the rendering of an image. Ansel Adams was very concerned with density as well, choosing not to exceed the density limitation of the film's ability to capture tonality. Ansel discovered that the film's non-linear development potential allowed him (and at the same time constricted him) to expose for threshold (because it didn't move with development) and control the highlight density with time and temperature of the film development. Once the film was developed with appropriate shadow placement and high values development, Ansel controlled the gamma of his pictures with graded papers in conjunction with the negative's enlargement illumination. Considering the Callier effect, he chose diffusion, condenser, or point source illumination to control the scattering of light in the heavier densities of the highs. Multiple DeBeers paper developers were used as well, to control silver deposition on the paper. MegaVision's initial efforts chose to imbue a capture with different contrast characteristics. With no standard in place, MegaVision came up with a scheme that made sense for the target that would be used to render the first digital images. MegaVision used Density Range as the descriptor of the contrast of the digital image. Density values are known as D-log numbers, a logarithmic number progression used to communicate density. Ansel used these numbers, as do modern silver sensitized photo paper makers. Printing press operators use these numbers. MegaVision thought that it would be prudent to make a digital emulsion that conformed to the density numbers the target was measured with. The system was successful, and it hasn't been changed because it's still the best. If the paper target measures 2.0 and the photographer shoots a MegaVision picture with a setting of 2.0, you'll get perfect contrast for the target. It's an approach that is simple, elegant, and straightforward. |