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Colour

The problem

Your LED wash mixes red, green, blue and white; the LED bar has RGB only; the beam mover has a colour wheel and nothing else; the spot has CMY plus a wheel. You build a nice "Deep blue" on the wash, and on the other fixtures it looks purple, or does nothing at all, or the preset simply doesn't apply. Then the whites don't match either, and a change from blue to yellow makes the room suddenly brighter.

Colour is one preset type, Color, in the attribute tree (see Attributes), but behind it are very different systems.

The idea: three colour systems, one Color preset type

The manual distinguishes three things that are easy to confuse, partly because MA renamed them over the years:

MixColor
Colour mixed from three or more variable emitters or filters: additive LEDs (red, green, blue, white, amber, UV, lime …) or subtractive CMY flags. MA defines 22 named mix colours (Red, Green, Blue, Amber, White, Warm White, Cool White, UV, Lime, …). (MixColor used to be called ColorMix or ColorDim; those names are obsolete.)
Colour wheel
Fixed filters on a wheel: a limited set of slots, often with split colours and a continuous spin.
ColorMix (today's meaning)
A fixture's built-in colour macros, factory-defined colours (often matched to gel colours) produced by whatever system the fixture has. In the Control preset type the same word also names a colour-fade speed channel.

CMY and RGB: opposite physics, one set of attributes

An RGB (LED) fixture adds light: red, green and blue emitters at zero are dark, all three at full make white. A CMY fixture works the other way round: a white lamp shines through three colour flags, cyan, magenta and yellow, and each flag takes away one part of the light. All flags out is open white; cyan takes away red, magenta takes away green, yellow takes away blue. So "red" on a CMY spot means magenta and yellow in, cyan out.

grandMA2 hides that difference. The manual says both are the same MixColor attributes (ColorRGB1 to 22), "independent on it being a CMY or LED color system"; only the physical range is reversed, 0 to 1 for light that is added, 1 to 0 for a filter that subtracts. In practice that means you set colour the same way on both: the colour picker (HSB, CMY or RGB entry) and the MixColor values describe the colour you want, and the fixture type turns it into emitter levels or flag positions.

To verify in onPC: check 36

What doesn't carry over is the look. CMY flags in front of a bright lamp give soft pastels and an open white, but deep saturated colours are darker; RGB LEDs give strong saturated colours but often a poor white. The same values on both rarely match by eye, which is why colour presets are tuned per fixture type (see Make one colour preset work across fixture types). A CMY spot often has a colour wheel as well, for saturated colours the flags can't reach; the colour picker's preferred engine decides which one it uses.

Two details that explain odd behaviour:

  • LED fixtures without a dimmer get a virtual dimmer in the fixture type. Without it, the colour attributes are the intensity, and fading the "dimmer" changes the colour. The manual notes that this "is not the behavior most users expect".
  • MixColor attributes expect to sit at 100% by default; the virtual dimmer does the fading.

The colour picker translates colour for each fixture

When you pick a colour in the colour picker (HSB, CMY or RGB, a gel from the swatch book, or predefined colours), grandMA2 translates that colour into whatever attributes each selected fixture has. You choose the preferred engine: Prefer MixColor (the usual default), MixColor only or ColorWheel only. For fixtures with more than three emitters, the Q fader decides how extra emitters (white, amber …) are used: RGB only (Primary), everything (Max), or the special emitter alone (Pure).

The same translation happens when you copy colour from one fixture to another with At: the temporary At filter offers MixColor, Color Wheel or both as the target system.

White isn't one colour: CTO and colour temperature

"White" from a discharge spot, a cheap LED bar and an RGBW wash are three different whites. Light sources have a colour temperature, given in kelvin: around 3,000 K looks warm and yellowish (a halogen lamp), 6,000 K and above looks cold and bluish (most discharge lamps and many white LEDs). Put a cold beam next to a warm wash and the white looks sloppy, as if one fixture were broken.

CTO (colour temperature orange) is the classic correction: a filter that lowers the colour temperature and makes white warmer. Moving lights have it as a CTO flag or wheel, often with a variable amount, next to their CMY mixing; some also have CTB (colour temperature blue) to make it colder. LED fixtures do the same electronically: a white or colour-temperature channel (often called CCT), or warm and cold white emitters in the mix.

In grandMA2, CTO is an attribute like any other, in the Color preset type next to MixColor and the colour wheel. That has three consequences:

  • A colour preset can include it. A Warm white preset might use CTO on the spots, a colour-temperature channel on the washes and a mix of white and amber on the bars, so it works best as a global preset with values per fixture type (see Make one colour preset work across fixture types).
  • It belongs to colour for filters, worlds and Update: a Color-only filter stores or plays CTO too, and a stray CTO value left in a cue will tint every colour after it.
  • MA's 22 named mix colours include White, Warm White and Cool White, but those are mix values; whether the colour picker also sets a fixture's CTO depends on the fixture type.

To verify in onPC: check 35

Practice

The manual doesn't explain colour temperature or CTO; this section is general lighting knowledge. In a dark rave room, white is one of your strongest looks, so it's worth one evening to match the whites of all fixture types and store Cold white and Warm white as global presets. Cold white beams on the drop against a warm breakdown is a contrast that costs no extra fixtures.

Presets across fixture types: why "Red" isn't automatic

Three mechanisms decide what "Red" does on each fixture, and they're easy to mix up:

  • A universal preset stores one set of values for everyone. But the manual has a catch: universal presets are only universal for attributes flagged Universal in the fixture type; for all others they "act like Global presets". And even where they do work, the same RGB numbers look different on different LEDs, and mean nothing to a colour wheel.
  • A global preset stores values per fixture type. One preset "Red" can hold the wash's RGBW values, the bar's RGB values and the beam's wheel slot, each tuned by eye.
  • A preset reference in the fixture type maps the reference colours to this fixture type's own values. MA recommends it especially for colour, "since the colors of every fixture and manufacturer may vary greatly". It's also what Auto Create builds on.

Practice

For colours that work across a mixed rig, use global colour presets, one per colour in a fixed slot, and tune each fixture type by eye until they match on stage. A wheel-only fixture gets the nearest slot: plan the palette around the colours the wheel has, or leave it open for some colours. Auto Create additional presets can generate a first grid of global mix colours to tune from. The steps: Make one colour preset work across fixture types.

Colours aren't equally bright

The washes sit at 40% in deep blue during a breakdown. You switch the colour look to yellow, the dimmer doesn't move, and the room suddenly looks twice as bright. Every colour change is also an intensity change, and in a dark room that's the change people notice first. Tuning the hue per fixture type doesn't fix it, and nothing in the console does it for you.

Interpretation

This is how eyes and LEDs work, not something in the manual. The eye is most sensitive to green and yellow, so deep blue and deep red look dim at the same power. Saturated colours use fewer emitters than white, so they're less light. On an RGBW fixture the white emitter often outshines the other three together. And dark-adapted eyes see blue as relatively brighter and red as darker, so balance in the room's real conditions.

The manual describes no colour calibration; the fixture type only stores a display colour per attribute, for the stage view. So you balance by eye and store the result where it stays:

  • Colour presets mixed below full. The picker's HSB view has a Brightness fader, so a bright colour can be stored at 35% instead of 100%. Global presets keep this per fixture type, and the dimmer stays free for the intensity layer.
  • A dimmer value next to the colour, in a colour look sequence or a mixed preset in the All pool. This breaks the colour-only layer busking relies on (see Colour concepts for busking), so keep it for cue-list shows.
  • A DMX profile on a colour attribute, for example capping a white emitter that drowns everything. It acts on every colour using that emitter, so it fixes an emitter, not a colour.
  • Group masters even out fixture types (bars too bright next to the washes), but don't follow the colour.
  • The fixture's own modes: some LEDs have calibrated colour modes or an output limit; check those first.
Every colour preset at full colour change = brightness change White Yellow Cyan Green Magenta Red Blue 100% 100% 100% 100% 100% 100% 100% Balanced colour presets bright colours mixed lower, to a reference reference: Magenta max White Yellow Cyan Green Magenta Red Blue 30% 30% 35% 40% 100% 100% 100% bar: brightness you see at the same dimmer level (rough, not measured) · %: colour Brightness stored in the preset
The same dimmer level in seven colours. Left: every preset at full, so changing colour changes brightness. Right: the bright colours are stored at lower Brightness to match a reference; blue can't go any higher and stays dimmer.

Practice

  1. Pick a reference colour in the middle (magenta, red or a mid blue), not deep blue, or you throw away most of the output for the bright colours.
  2. Balance by eye, at show distance, in haze, at a typical dimmer level (40–60%): switch between the reference and each colour and lower the bright one's Brightness until the switch no longer jumps.
  3. Keep the compensation in the colour presets, so it travels with every look and a new venue means retuning a few presets.
  4. Accept that blue stays dim, or bring it up with the intensity layer where it matters.
  5. Keep a separate full white for hits: a balanced white at 30% isn't a hit.

Lower emitter levels cost resolution: on an 8-bit fixture a colour at 30% with the dimmer at 10% leaves few DMX steps, and slow fades near black can step visibly (see Fixtures and patch).

To verify in onPC: check 22

When it matters, and when not

  • A single fixture type: universal or global makes little difference.
  • Mixed LED fixtures: global colour presets, tuned per type. This is the most common real-world need.
  • Wheels and mixing in one rig: plan the palette around the wheel.
  • Spots with CTO next to LEDs: match the whites once and store them as global presets.
  • Busking colour looks in a dark room: balance the brightness of the colour presets, or every look change is also an intensity jump.
  • Cue-list shows with fades between colours: the fade softens the jump, but a yellow scene still reads brighter than a blue one.
  • Skip at first: building your own fixture types or preset references. Only needed when the library fixture isn't good enough.

Sources