Question for artists (paint)

[Ulysees]

When you sketch to paint which pencil do you use?
I use acrylics and oils and have just been painting freehand but want to add more detail but I'm not sure where to start?

something soft ish so it doesn't mark the paper too much (I use an illustration board,quite light but smooth- then draw over in ink and add liquid watercolour0 Can't tell you what hardness the pencil is though as it's old and worn !!

4B or 5B pencil?

thanks for that