In this video we learn how to control contrast in photography.
Tags:The Control of Contrast in Photography,control of contrast,difused highlights,history of photography,how to expose an image,lighting education in photography,lighting in photography,photography tips,software cinema
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Male1: There are many different methods of controlling light for still and moving images. This section will cover the control of contrast.
Contrast is the measure of the differences in brightness between areas on an object. The predominant controls here are the distance of the main light source to the subject, the distance of the ambient source to the subject, the distance of the main light source to the ambient ratio, and the efficiency of the ambient source.
Male2: What I do ultimately is self photography for reproduction. It’s going to end up in a brochure, on a website, in a catalogue, in a print ad, on a billboard, and it’s very important that I understand contrast and how to properly expose an image, and how to, you know, have the dynamic range that I want in order for that image to reproduce appropriately in each one of those mediums.
Male1: The first method of controlling contrast between the diffused value and their shadow is altering the distance from the main light source to the subject. For this image of an old motion picture light a small Chimera light bank will set at the distance of approximately eight feet from the subject area. As seen in the first image the contrast between the diffused value or true tone of the object and the shadow is relatively high, but there is still detail on the shadow area of the object.
By moving the light bank closer to the subject area, several changes in the lighting occur because the size of the source increases, the quality of light becomes softer, but more important is the increase in the intensity of light on the diffused of the object with the source now at three feet.
In the first image, the contrast created by a light source at a distance of eight feet was determined by comparing the amount of light striking the diffused area to the value of the shadow area. By moving the source closer the intensity of light striking the object increases significantly while the amount of light on the shadow are remain relatively unchanged. The new exposure reading for the increase of light intensity required a decrease in aperture or F stop for a correct exposure of the diffused value. The result is an increase in contrast between the diffused value and the shadow.
Another method of controlling contrast between the diffused value and the shadow is the distance of the ambient source to the subject. The ambient source is defined in this case as any reflective surface that bounces light energy back into the subject area such as a bounce card or white wall.
With our model Katie seated in the studio Bill Holshevnikoff illuminates Katie directly with an areas on 575 lot HMI daylight source. On the background surface for separation an area lot 125 compact HMI directed Katie at the black background. Overhead hanging on is an area compact 200 lot HMI texture with a small Chimera light bank attached on the front of the light. Placed on the face of the Chimera light bank is a 40 degrees soft egg crate grid to control a spill light from the fixture.
Holshevnikoff directs his assistant to place for Chimera panel frame with diffusion fabric between the key light and our model Katie. The light from the source illuminates the diffusion fabric which will serve as the main light source for the subject.
Look at the first image shows relatively high contrast ratio from diffused to shadow on Katie’s face. At this point there’s a lack of ambient or a bounce light returning to the shadow side of Katie’s face. Holshevnikoff now directs his assistant to bring in a second Chimera frame. This one covered in reflective white fabric to serve as ambient bounce source for the shadow side of the subject. Adjusting this fill from the key light to bounce off the front edge of the white reflector panel can also increase the level of bounce fill light. The diagram shows a relative placement of the main light source and the Chimera bounce panel.
I look at the first image using the diffusion frame only shows high contrast with no fill light on the shadow side of our subject. By introducing an ambient bounce source at the distance of approximately four feet, the density of the shadow decreases resulting in a decrease in contrast.
To further increase the amount of bounce light on the subject, the distance of the ambient source to the subject is decreased increasing the effect of the ambient fill light on Katie. Returning to our first image, we can see that the introduction of an ambient light source decrease the contrast between the diffused and shadow noticeably, but when the ambient source is moved closer to the subject the reduction in contrast is significant.