Glossary 2 Flashcards
histogram
Video scope that shows distribution of pixels from super black on the left to super white on the right, scaling from dark to light. It has a lot of utility in Photoshop, but ALMOST NO UTILITY IN FINAL CUT. It’s ONE valuable function is to ALLOW YOU TO SET THE BLACK LEVEL.
waveform
Video scope that tells us everything we need to know about black and white. We can make left to right statements like “the left side is brighter than the right” or “the right side is brighter than the left”, but we can’t interchange up and down statements. Down is dark, up is bright. Period.
We divide the up-down waveform monitor into six sections: The negatives (super blacks, not possible), the shadows at 0-33%, mid tones from 33-66%, highlights from 66-100%.
Anything above 100 is also an illegal value, this one called super white.
The problem is that every single digital camera shoots into the super white value, which means that if you don’t color correct, they are already illegal for all broadcast, cable, and DVD.
A percentage. Everything about black and white, nothing about color.
IRE
An IRE is a unit used in the measurement of composite video signals. Its name is derived from the initials of the Institute of Radio Engineers.[1]
A value of 100 IRE was originally defined to be the range from black to white in a video signal. A value of 0 IRE corresponds to the voltage value of the signal during the blanking period. The sync pulse is normally 40 IRE below this 0 IRE value, so the total range covered from peak to trough of an all white signal would be 140 IRE.
The reason IRE is a relative measurement (percent) is because a video signal may be any amplitude. This unit is used in the ITU-R BT.470 which defines PAL, NTSC and SECAM.[2]
Vectorscope
Video scope that tells us everything we need to know about color. Every shade of black, white, and grey is a single dot in the center of the vectorscope. Black, white, and greys are all a knitting needle that perpendicularly through the center of the “grapefruit” vectorscope, and if we sliced the “grapefruit” horizontally at the equator, we end up with the top down view (THE view) of the vectorscope, with all the colors labeled around the edges. The opposite colors cancel to grey (red is the opposite of cyan, and meets in the middle at grey) (the opposite of magenta is green, meets in the middle at grey) (the opposite to blue is yellow, and meets in the middle at grey) So adding opposite colors cancels. For example, in green screen, the way you take green out is to add magenta.
Also, equal amounts of red, green, and blue = grey. Equal amounts of dark red, dark green, and dark blue = dark grey.
A rephrasing of this statement makes color correction possible: “If something is supposed to be grey, then it must contain equal amounts of red, green, and blue.”
high contrast
lots of pixels between the darkest and the lightest pixel
If you shoot on a bright, sunshiny day and you want to make it look cloudy, raise the _____ levels
black
If you shoot on a foggy day and you want to make it look like the fog isn’t there, pull you _____ levels ____
black
down
The three fireable offenses for an editor:
- Audio levels that exceed 0dB
- White levels that exceed 100%
- Chroma levels that are oversaturated
How do you determine if your chroma levels are okay?
Connect the dots in the vectorscope of the color labels (connect the tops of the targets), and if your color levels are inside that six-sided polygon, it is a generally safe assumption to say that your chroma levels are okay. If they exceed a line connecting those tops, your chroma levels are oversaturated.
What gives our skin color is not the skin, but the:
red blood under the skin
The flesh tone line represents:
the color of red blood under skin, no matter what race you are. If you’re color correcting anyone but an Asian, their skin color needs to be on the red line, or two degrees above it. If you’re color correcting an Asian, it’s on the line or two degrees below it. It sits between yellow and red, closer to red. It is seen on all FCPX vectorscopes.
The difference is one of saturation, not hue. The hue of all flesh tones comes from the presence of hemoglobin, the iron-based molecule in blood that transports oxygen. The differences in saturation are caused by differences in the amount of melanin in the skin tissue, a natural defense against the damaging effects of ultra-violet radiation. It’s why some people tan and some people burn.
To be absolutely clear, all healthy flesh tones have the same hue. If you have jaundice, your skin will become yellowish from the presence of bilirubin, and it will appear little to the left of the line. If you are hypothermic, your surface circulation will shut down, and your skin will “turn blue”, because of the lack of oxygenated hemoglobin. Your hue will lie on the right side of the line. Both situations can easily be color-corrected, but it is best to seek urgent medical attention.
This leads us to some interesting questions of semantics. We are, literally, all the same under the skin. No one is black or white, unless they live in a grayscale world. No one is yellow, unless they have jaundice. You can feel blue, but you can’t look blue and live very long. There are, in fact, no colored people, and even the progressive “people of color” implies an impossible “not people of color”. We could say “people of hue”, but even that is not strictly correct; we’d have to say “people of saturation”. And terms like “mulatto” or “half-breed” are meaningless on the flesh-tone line: half of what, exactly?
The flesh tone line summarizes both our common origins and our individual heritages in one handy axis. It’s a pity that its implications are not more widely understood.
Shortcut for Color Board
Command 6
The principle or main thing that I have to do is:
greyscale adjustments
The color board has three components:
Color (which translates to hue)
Saturation (the amount of color)
Exposure (which translates to grayscale)
Each one of the three settings in the color board has four _____
pucks
