Making Rock Images: Part 3

I have previously written two posts on making rock images and they can be read here and here.

As I mentioned in one of the prior posts, if the rock sample is not polished (and they generally are not when bought through e-Bay... plus they are also less expensive when not bought polished) then it is best photographed wet, as the coating of water really brings out the color and contrast in the stone. I first had to try to figure out what exactly wet means. I discovered that it does not mean a pool of water on the rock surface. Yes, this will make the rock stay wet longer, but you will also get very small air bubbles as well as dust particles floating in the water that will be visible in the image. So wet really only means moist. Just a very light covering of moisture to make the surface of the rock wet without having a three dimensional pool of water is what you are aiming for.

The downside of such a thin coating of moisture is that it dries out very quickly. So here is what I do. I keep a moist washcloth next to the tripod and use it to wipe the surface of the rock and then compose. By the time I find something interesting the rock has dried out, so I wipe it down again to fine tune the composition and manually focus. If it is still moist (look at the edges of the viewfinder and see if the drying out is 'creeping in') I shoot. If the edges are starting to dry out, as they usually are, I hold the rock sample in place with one hand, wipe the area of the rock I am photographing with the washcloth using the other hand, and quickly make any fine adjustments needed to the position of the rock while looking through the viewfinder. Usually I don't have to refocus, but if there is time I might do that as well.

I have tried putting the rock in a bucket of water for a few minutes before shooting to see if it would 'saturate' and stay wet longer, but this didn't really seem to help.

What about lighting a wet rock...ah, the reflections and highlights coming off the wet surface....but there is a way around this and that is to use cross-polarization. I was thinking of writing a whole post about this technique but, frankly, I don't think I could do a better job than this....so have a read of it!