I told you that I might be reworking this one... here is the result. I lightened the area under the big shell a bit — I think it now gives more of an impression of light bouncing off the sand onto the underside of the shell. Not a drastic re-do, but enough for me to finally feel that it is DONE. Yay! Below is the original so you can compare... you can see that I played with the color balance and brightness/contrast in Photoshop a bit too, the final version above is closer to the original painting.