Gel

What this is about

Gels split into two jobs that feel similar and are not. Correction gels make one source behave like another so a mixed room reads as consistent — that is craft. Effect gels push a scene toward a color the story wants: the blue of a fictional moon, the sodium orange of a street, the sickly green of a corridor. A colored source is also close to permanent, since separating a gelled key from the rest of a shot in the grade is expensive work.

A term only helps when everyone on set means the same thing by it — so what follows is how it is used, not a dictionary definition.

What runs differently here

Where this differs from the general case:

• Correction gels match sources to one another; effect gels give the scene a color the story asks for.
• Plus-green and minus-green gels exist for the tint axis, mainly to tame fluorescent tubes and older LED fixtures.
• Every gel costs output, and dark saturated colors can swallow most of a lamp before anything reaches the set.

With TillyGen

TillyGen's equipment list books gel rolls with the lamps they belong to, so a mixed-source location arrives with the correction it needs.

Change one constraint and the consequences travel through the whole plan: affected shots are flagged, the call sheet is regenerated, and nobody keeps working from yesterday's version.