1 The Director of Photography – an overview
1 The Director of Photography – an overview
1 The Director of Photography – an overview
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1-stop r<strong>an</strong>ge � brightness r<strong>an</strong>ge <strong>of</strong> 2:1<br />
2-stop r<strong>an</strong>ge � brightness r<strong>an</strong>ge <strong>of</strong> 4:1<br />
3-stop r<strong>an</strong>ge � brightness r<strong>an</strong>ge <strong>of</strong> 8:1<br />
4-stop r<strong>an</strong>ge � brightness r<strong>an</strong>ge <strong>of</strong> 16:1<br />
5-stop r<strong>an</strong>ge � brightness r<strong>an</strong>ge <strong>of</strong> 32:1<br />
6-stop r<strong>an</strong>ge � brightness r<strong>an</strong>ge <strong>of</strong> 64:1<br />
7-stop r<strong>an</strong>ge � brightness r<strong>an</strong>ge <strong>of</strong> 128:1<br />
Figure 11.1 <strong>The</strong> relationship<br />
between the brightness measured<br />
in stops <strong>an</strong>d the lighting ratio<br />
11<br />
Lighting ratios<br />
Defining a lighting ratio<br />
A lighting ratio is the figure we give to a measured relative difference<br />
in brightness between two parts <strong>of</strong> a scene.As opening the aperture by<br />
one stop doubles the amount <strong>of</strong> light reaching the film, two surfaces<br />
where one is brighter by one stop <strong>of</strong> exposure th<strong>an</strong> the other will<br />
therefore have a lighting ratio <strong>of</strong> 2:1.<br />
Where there are several surfaces, each a stop brighter th<strong>an</strong> the next,<br />
each time you open the r<strong>an</strong>ge <strong>of</strong> your comparative readings by one stop<br />
the amount <strong>of</strong> light reaching the film will double, therefore the lighting<br />
ratio will double. Figure 11.1 shows the relationship between the difference<br />
in brightness measured in stops against the result<strong>an</strong>t lighting ratio.<br />
Visualizing lighting ratios<br />
It is import<strong>an</strong>t, before lighting a scene, to be able to visualize the lighting<br />
ratio you are going to use. It is very time-consuming to have to<br />
ch<strong>an</strong>ge your ratios after you thought you had finished lighting the set;<br />
it is unpr<strong>of</strong>essional <strong>an</strong>d the delay makes you unpopular with the production<br />
<strong>of</strong>fice.<br />
In order to easily visualize lighting ratios, look at Figure 11.2. Here<br />
the lighting ratio between the highlight <strong>an</strong>d the body <strong>of</strong> the sphere is 2:1.<br />
<strong>The</strong> ratio between sphere <strong>an</strong>d shadow is again 2:1. From shadow to the<br />
deep shadow it is 4:1.<strong>The</strong> chart at the lower half <strong>of</strong> Figure 11.2 shows all<br />
the various ratios between all the parts <strong>of</strong> the sphere <strong>an</strong>d its shadow.<br />
Keep this sphere in mind <strong>an</strong>d you will easily visualize all the import<strong>an</strong>t<br />
brightnesses on <strong>an</strong>y set.<br />
Lighting ratios for film <strong>an</strong>d television<br />
Even the finest cinema screen c<strong>an</strong> only reflect a limited amount <strong>of</strong> light.<br />
In a very good cinema the difference between the darkest perceivable<br />
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