Get this effect
Switch to Code in your Claude Desktop App
Install the skill (once)
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Install the Recharm video effects skill: download https://recharm-growth-staging.s3.us-east-2.amazonaws.com/website/downloads/recharm-video-effects.zip and unzip it into ~/.claude/skillsAsk for the effect
Add a day for night to input.mp4 Second the shot starts turning to night: 1.0 Seconds the change from day to night takes: 1.0
Several videos, several effects, one ask
Put your clips in the folder, mention them with @, and ask for everything at once. Claude runs one tested script after another on each clip, then joins them.
Add a day for night to @clip1.mp4, put a sale badge on @clip2.mp4, give @clip3.mp4 a VHS look, then join all three with crossfades.
Settings you can change
Ask Claude to change any of these, or edit them at the top of the command.
| Setting | Default | What it does |
|---|---|---|
START | 1.0 | Second the shot starts turning to night. 0 makes it night from the first frame. |
FADE | 1.0 | Seconds the change from day to night takes. |
GAMMA | 0.75 | How dark the night is. Lower sinks the shadows and mid-tones further; 1 leaves them. |
Without the skill
Don’t want to install the skill? Paste this prompt into Claude Code and Claude writes the command itself.
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Turn input.mp4 from day into night. Leave the first 1 second untouched, then over 1.0 to 2.0 seconds blend smoothly into a night grade and keep that grade to the end. The night grade: remix the color channels toward blue (new red = 0.30R + 0.20G + 0.05B, new green = 0.15R + 0.40G + 0.10B, new blue = 0.12R + 0.35G + 0.63B), then apply gamma 0.75 and brightness -0.04 (ffmpeg eq), then a vignette with angle PI/4 so the edges darken. Once graded, the frame should average about a quarter of the original brightness, with blue clearly the strongest channel (around RGB 35, 50, 110 on average). Add no text (any text you do add should be drawn with Pillow, not ffmpeg's drawtext). Keep the size, the 30fps frame rate, the 6 second length and the audio. Use ffmpeg and save it as output.mp4.Run it without Claude
This is the exact command we tested. Save it as day-for-night.sh and run:
sh day-for-night.sh input.mp4 output.mp4Show the command
#!/bin/sh
# Day for night: the daylight shot cools and darkens into blue moonlight between 1s and 2s, then stays night.
# Usage: sh day-for-night.sh input.mp4 output.mp4
set -e
IN="$1"; OUT="$2"
START=1.0 # second the shot starts turning to night
FADE=1.0 # seconds the change from day to night takes
GAMMA=0.75 # below 1 sinks the shadows and mid-tones further
# The night grade: each channel remixed toward blue (warm light drained, blue kept), darkened, edges dimmed
NIGHT="colorchannelmixer=rr=0.30:rg=0.20:rb=0.05:gr=0.15:gg=0.40:gb=0.10:br=0.12:bg=0.35:bb=0.63,\
eq=gamma=$GAMMA:brightness=-0.04,vignette=PI/4"
# Blend from the untouched shot to the graded one as the clock passes START
ffmpeg -y -i "$IN" -filter_complex "\
[0:v]format=gbrp,split[day][n];\
[n]$NIGHT[night];\
[day][night]blend=all_expr='A+(B-A)*clip((T-$START)/$FADE,0,1)',fps=30,format=yuv420p[v]" \
-map "[v]" -map 0:a -c:v libx264 -crf 18 -pix_fmt yuv420p -c:a copy "$OUT"
