Read the stage colour from the template styleEach of the eighteen template styles carries a stage entry of three colours: edge, mid and core. Scholar is navy (#060D1E, #0C1B36, #173058); Lattice is near-black blue-grey (#04070A, #0A131B, #12212E); Folio is a warm brown (#171009, #251A10, #3A2A1A); Beacon is a dark violet-black (#08080E, #14141F, #232338); Slate is a cool slate (#0E141A, #18212A, #26323E). The maroon family: Regalia is a deep maroon (#14050A, #2A0A11, #5E1220); Garnet is a near-black wine (#0A0305, #1A080D, #3D1018); Vellum is a warm oxblood (#12060A, #24101A, #3D1820); Ledger is a quiet maroon-charcoal (#12070A, #1F0D12, #351B20). Vibrance is a bright navy (#152348, #1F3260, #2E4A85). Lilac is a pale lavender (#DCD3F7, #EAE5FB, #FAF9FF). Cobalt is a pale grey (#D5D7E0, #E6E7EC, #F7F7F9). Blossom is a soft white-grey (#E4E4E7, #EEEEF0, #F9F9FA). Crayon is a cool light grey (#E2E2E8, #ECECF1, #F8F8FA). Azure is a pale blue-grey (#DDE2EA, #E9EDF3, #F7F9FC). Onyx is a neutral light grey (#D9D9D9, #E6E6E6, #F6F6F6). Bulletin is a plain light grey (#D7D7D7, #E5E5E5, #F5F5F5). Tangerine is a warm light grey (#E6E3E0, #EFEDEB, #FAF9F8). Both the still plates and the live renderer read the same three values, so they always agree.
Draw the Presenter + Animated stageA full-frame radial gradient centred at (1500, 430) with a 1500-pixel radius puts the pool of light behind the presenter's card, right of centre. Each point blends core to mid over the first half of the radius and mid to edge over the second, through a smoothstep ease so no banding ring appears. It is drawn at one sixth of full size, scaled up smoothly and blurred by 3 pixels, which makes it both fast and seamless.
Cast the cards' shadowsUnder each card's position a rounded rectangle is drawn, offset 6 pixels right and 16 to 18 pixels down, with a 30-pixel radius, blurred by 28 pixels and used to darken the stage toward a near-black #020610. The cards then look as if they sit slightly in front of the ground rather than printed on it.
Paint the presenter's card wellThe presenter's card, 498×736 at (1387, 168), gets its own small radial, a step lighter than the stage in the same hue: its edge is the stage edge ×1.35 and its centre the stage core ×1.18, centred a third of the way down the card where the head will be. It is cut to a 26-pixel rounded corner and pasted onto the stage.
Draw the Presenter Centred stageA second full-frame radial, centred low at (960, 560) with a 1250-pixel radius, and on top of it a very soft ellipse of light (from x 340 to 1580, y 210 to the bottom edge, blurred by 170 pixels) in the card's centre colour. The presenter stands in that pool, centred, with the captions running across the bottom.
Cut the corner masksTwo greyscale masks with 26-pixel rounded corners are drawn at the exact card sizes, 1310×736 for the slide and 498×736 for the presenter. The compositor applies them to give both cards their rounded corners, since the video tools have no rounded rectangle of their own.
Measure the greenNine frames are sampled from 5% to 95% of the recording. Backing pixels are found by shape rather than hue (green exceeds red by 40, exceeds blue by 60 and is above 90), which holds whether the cloth is lit warm or cool. The key colour is the median of all of them.
Try the key's reach instead of guessing itFor each of eight reach values (0.06, 0.08, 0.10, 0.12, 0.14, 0.17, 0.20, 0.24) the real matte is formed by the same filter the render uses, and scored on two questions: is the certain backing gone (at most 0.05% may survive), and is the certain presenter still all there. The smallest reach that clears the backing without costing the presenter more than 0.2% is chosen, then moved one rung wider only if that rung is free. Green spill on hair and shoulders is neutralised at half strength.
Open up the shadow sideA studio key light with no fill leaves the far cheek two or three stops down, which reads as modelling against green and as a hole against a dark card. A gentle tone curve lifts the bottom of the range, leaves the midtones almost alone and the highlights exactly alone. At the default strength of 0.35 the black point rises to about 0.04, the quarter-tone from 0.20 to about 0.28, and the curve is back on the diagonal by the top.
Composite each layoutPresenter + Animated: the slide goes into its rounded card, the keyed presenter is scaled to cover his card and centre-cropped with his feet kept, and only the finished card is masked. Presenter Centred: the keyed presenter is scaled to 960 pixels tall and positioned so his measured head line falls on the frame's centre. Presenter + Captions: the presenter is scaled to 1004 pixels tall on the right, over the painted caption plate. Every layout uses one shared key-and-look string, so the presenter never changes complexion at a cut.
