It is a question I often hear when talking about bringing a painting from concept to finished product.
My start is a spark of inspiration in my head, from something I see, or read about or a photograph. Or all of the above!
Most of my paintings begin in a sketchbook or on a scrap of paper. Some are scribbled thumbnail sketches where I work out values and composition. Others have additional notes about light or colour so I can keep details fresh in my head back in the studio. I must have sheaves of scraps of paper as well as sketchbooks. I don't see my sketchbooks as little works of art, to remain pristine and perfect. My sketchbooks are messy and paint strewn, scattered with mediums from pencil to oil paint and are the snapshots that serve as my working tools which lead to a painting. They are battered, dog-eared and used, just as any good tool should be.
This first sketch gives me colour note reminders, rough blocking of values in the shadows and overall shapes. Of course it is nowhere near perfect nor is the boat shape. All that will come together when I start the drawing for the final painting. But the sketch is the germinated seed that grows slowly towards the light. It gives me all the information I need in case I never see this particular boat, water or light again.
Becoming very familiar with your subject in its natural setting, especially if there is just a photographic reference, enables you to have the freedom to know how the environment affects the subject. You don't even need the exact subject if you make an accurate enough sketch and allow enough time to absorb colour information.
Here I instinctively know how light curves around the shape of the boat, where little highlights hit and how the water reacts to wind and movement. I know it because I have seen a boat on water a thousand times, perhaps 10,000 times in my life. I have spent hours roaming beaches in all weathers, watching waves both gentle and powerful, water both flat and rough. Without ever seeing a scene again, and armed with a sketch, colour and value notes, I have the tools needed to create a painting.