Better grading of the jumpsuit

README.md

@@ -140,6 +140,7 @@ Keylight-style color-difference keyer) with a `color_grade` step. Key fields:
 | `despill_bias` | RGB the keyed *edges* shift toward. A light neutral/skin tone reads better than cool blue. |
 | `despill_strength` | How hard the edge/dominant-green despill pulls toward `despill_bias`. |
 | `spill_suppress` | **Interior green-limiter — see below.** |
+| `yellow_protect` | Shields saturated yellows/warm fabrics from `spill_suppress` (0–1). |
 | `edge_erode` | Shrinks the alpha edge by N passes to kill green fringe (0–5). |
 
 **`spill_suppress` — the bald-head knob.** The regular despill only acts where
@@ -158,6 +159,14 @@ Green is only ever *reduced*, never boosted, so clean pixels are untouched.
 Start around `0.6`; go past `1.0` for heavy close-up spill. If skin tips
 magenta/pink, ease back down. Range is `0.0`–`2.0`.
 
+**`yellow_protect` — keep yellows yellow.** Because `spill_suppress` caps green
+*everywhere*, it also drains green from things that are legitimately yellow (a
+yellow jumpsuit, warm props), turning them orange. Blue is the tell: skin keeps
+some blue, saturated yellow fabric reflects almost none. `yellow_protect`
+(0.0–1.0) gates the green-limiter back down where `min(r,g) − b` is high
+(yellow) while leaving skin/scalp spill fully suppressed. Bump it toward `1.0`
+if warm colours go orange; leave at `0` if you have no strong yellows.
+
 #### Grade preview (`grade`)
 
 Iterate on keying/grading without running a full preprocess. It seeks a few