When the plane wave is incident at a non-normal angle at the time of recording, the pattern formed is more complex, but still acts as a negative lens if it is illuminated at the original angle. A lens is required in photography to record the image, whereas in holography, the light from the object is scattered directly onto the recording medium.

The concentration of dyes or silver halide crystals remaining on the film after development is referred to as optical density, or simply density; the optical density is proportional to the logarithm of the optical transmission coefficient of the developed film. A dark image on the negative is of higher density than a more transparent image. Claire Elise Campton (17 August 2016). "Film Photography". Photopholio. Archived from the original on 19 September 2016 . Retrieved 17 August 2016.

Holographic Film options

Three-dimensional holography could also boost the development of volumetric 3D printing, the researchers say. This technology could prove faster and more precise than traditional layer-by-layer 3D printing, since volumetric 3D printing allows for the simultaneous projection of the entire 3D pattern. Other applications include microscopy, visualization of medical data, and the design of surfaces with unique optical properties. www.loc.gov". loc.gov. 2014. Archived from the original on 19 September 2015 . Retrieved 8 August 2015. When a photograph is cut in half, each piece shows half of the scene. When a hologram is cut in half, the whole scene can still be seen in each piece. This is because, whereas each point in a photograph only represents light scattered from a single point in the scene, each point on a holographic recording includes information about light scattered from every point in the scene. It can be thought of as viewing a street outside a house through a 120cm ×120cm (4ft ×4ft) window, then through a 60cm ×120cm (2ft ×4ft) window. One can see all of the same things through the smaller window (by moving the head to change the viewing angle), but the viewer can see more at once through the 120cm (4ft) window.

A hologram is made by superimposing a second wavefront (normally called the reference beam) on the wavefront of interest, generating an interference pattern which is recorded on a physical medium. When only the second wavefront illuminates the interference pattern, it is diffracted to recreate the original wavefront. Holograms can also be computer-generated by modelling the two wavefronts and combining them digitally. The resulting digital image is then printed onto a suitable mask or film and illuminated by a suitable source to reconstruct the wavefront of interest.For a better understanding of the process, it is necessary to understand interference and diffraction. Interference occurs when one or more wavefronts are superimposed. Diffraction occurs when a wavefront encounters an object. The process of producing a holographic reconstruction is explained below purely in terms of interference and diffraction. It is somewhat simplified but is accurate enough to give an understanding of how the holographic process works. For those unfamiliar with these concepts, it is worthwhile to read those articles before reading further in this article. Scientific Products". Ilford Photo. Archived from the original on 5 December 2015 . Retrieved 16 December 2015. It’s a considerable leap that could completely change people’s attitudes toward holography,” says Matusik. “We feel like neural networks were born for this task.” Experiments with color photography began almost as early as photography itself, but the three-color principle underlying all practical processes was not set forth until 1855, not demonstrated until 1861, and not generally accepted as "real" color photography until it had become an undeniable commercial reality in the early 20th century. Although color photographs of good quality were being made by the 1890s, they required special equipment, separate and long exposures through three color filters, complex printing or display procedures, and highly specialized skills, so they were then exceedingly rare.