Series drift is usually blamed on the model. Check the tuning instead. The character was described from memory at every job, and memory slides off frequency a fraction at a time. “Jet-black hair in a low ponytail” in frame one becomes “dark sleek hair” by frame four, and the audience watches a stranger take her place. The repair is technical and dull, which is why it works: write her down once, on a signal card you paste rather than retype.
Five fixed lines, always in order
Age — a number, and at this desk a mature one. Hair — colour, length and one habitual style. Build — two or three words. Face — one or two details that endure every crop. Signature — the band, the hoop, the detail that survives any light. Everything else belongs to the changing line: outfit, corner, hour, monitor light. Changing lines are meant to change. Tuning lines are not.
State the lines plainly and positively; adjectives are reinterpreted at every attempt, concrete descriptions survive. And version the card: when she is deliberately changed, save the new text as version two with a date, so an old set can be remade exactly as it was.
Working from the card
Pair the card with changing lines that share one setting and one light, generate at the standard 6-credit cost, and keep the best third. Spend on repairs, transfers and upscales only after the cull. When a frame returns off character, the cause is almost always on the card: a changing line contradicted a fixed line, or a line was too vague to hold her.
What a card cannot do
It cannot hold a character who was never tuned. Tune her on paper first. The card is not where the imagination happens; it is where the imagination stays audible, frame after frame.