Catkin,there are 3 ways I create a painting,(1)direct on the spot (usually abroad when the light is more constant (2) from sketches on the spot with added colour notes, my favourite way and (3) digital camera when time is limited or its a busy street scene etc... were it would be inconvienent or impossible any other way.
Of course if I am doing subjects of time past, such as my tram paintings, then I have to use old, usually black and white pics plus memory and imagination and artists licence, at 78 years old I have no problem with tram colours, my usual means of travel when I was young.
RE St Phillips see post below. Eric