To make a sig I am 100% happy with takes up to an hour, once I know exactly how I'm going to approach it. Initial brainstorm and experimenting isn't included.
Making sigs is more than just taking a render, adding some brushes and C4D's. There's lighting, shadows, depth, perspective, and focal's to account for.
So the big things to worry about in a sig are
- Render
- Background
- Text
- Accents to the render/background (C4D's/Brushes/Pen Tooling/etc.)
- Render-Background distinction, while retaining depth and clarity
- Color palette, you need a couple of "base" colors, and then have several variations of those colors, and use them throughout the signature. Obviously this doesn't apply all the time
After all those things are accounted for and tweaked to your liking, it takes about an hour.