Editing Film speed (section)

====Saturation-based speed====
The ''saturation-based speed'' is defined as
:<math>S_{\mathrm{sat}}=\frac{78\;\text{lx⋅s}}{H_{\mathrm{sat}}}</math>,
where <math>H_{\mathrm{sat}}</math> is the maximum possible exposure that does not lead to a clipped or bloomed camera output. Typically, the lower limit of the saturation speed is determined by the sensor itself, but with the [[Gain (electronics)|gain]] of the amplifier between the sensor and the [[analog-to-digital converter]], the saturation speed can be increased. The factor 78 is chosen such that exposure settings based on a standard [[light meter]] and an 18-percent reflective surface will result in an image with a grey level of 18%/{{radic|2}}&nbsp;=&nbsp;12.7% of saturation. The factor {{radic|2}} indicates that there is half a stop of headroom to deal with [[specular reflection]]s that would appear brighter than a 100% reflecting diffuse white surface.<ref name="iso12232"/>