Tape-to-tape color correction – Apple Color 1.5 User Manual
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Once the camera negative has been conformed and the different shots physically glued
together onto alternating A and B rolls, the negative can be color-timed by being run
through an optical printer designed for this process. These machines shine filtered light
through the original negatives to expose an intermediate positive print, in the process
creating a single reel of film that is the color-corrected print.
The process of controlling the color of individual shots and doing scene-to-scene color
correction is accomplished with three controls to individually adjust the amount of red,
green, and blue light that exposes the film, using a series of optical filters and shutters.
Each of the red, green, and blue dials is adjusted in discrete increments called printer
points (with each point being a fraction of an f-stop, the scale used to measure film
exposure). Typically there’s a total range of 50 points, where point 25 is the original neutral
state for that color channel. Increasing or decreasing all three color channels together
darkens or brightens the image, while making disproportionate adjustments to the three
channels changes the color balance of the image relative to the adjustment.
The machine settings used for each shot can be stored (at one time using paper tape
technology) and recalled at any time, to ease subsequent retiming and adjustments, with
the printing process being automated once the manual timing is complete. Once the
intermediate print has been exposed, it can be developed and the final results projected.
Conform Negative
Final Film Print
Optical Color Timing
Camera Negative
While this system of color correction may seem cumbersome compared to today’s digital
tools for image manipulation, it’s an extremely effective means of primary color correction
for those who’ve mastered it.
Note: Color includes printer points controls for colorists who are familiar with this method
of color correction. For more information, see
.
Tape-to-Tape Color Correction
For projects shot on videotape (and for those shot on film that will not receive a second
telecine pass), the color correction process fits into the traditional video offline/online
workflow. Once the edit has been locked, the final master tape is assembled, either by
being reconformed on the system originally used to do the offline or by taking the EDL
(Edit Decision List) and original source tapes to an online suite compatible with the source
tape formats. For more information about EDLs, see
Importing Projects from Other Video
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Chapter 1
Color Correction Basics