Sea Shell pencil sketch for watercolor painting

Sea Shell watercolor reference photo

I have started to do a watercolor painting on sea shell.  The above is the reference photo I took for the painting.  It is going to be done on a 15 x 22 inches Arches watercolor paper.  I have divided the cropped and printed the photograph on paper.  Then the paper with the photographic image is divided into 4 x 4 grids using a dark marker.  Grids are also used to divide the watercolor paper and the image is then copy to a 15 x 22 watercolor papaer as shown on the first photo using a lead pencil.   I am going to apply the watercolor paint in layers  for this painting and will try to do light values first and will eventually proceed to the darkest vlaue.