Why are rocks prettier when they're wet?

Kelley's Island, near Sandusky, Ohio. Jane M. Mason (c).
Let me know if you would be interested in this photo as a 6x8" print.

Have you ever picked up a brightly colored wet rock? Maybe you tucked it into a pocket. Later, have you been surprised at how dull they look when dry?

Well, to me…this all has to do with how you paint rocks and water in watercolor. (It always comes back to art for me, doesn’t it?)

I’ve wondered, why does a rock look wet? Why can we (usually) see the area where the water came in contact with the rock? Why can we see where an edge delineates the border between wet and dry?

Why does the water touching something makes it appear to change its color?

I’m no scientist so I’ll explain this as I understand it. I’ll defer to any scientists who want to chime in 😊

Water is a liquid. The properties and surface tension of water mean that it is going to have a smooth liquid surface.

A rock, on the other hand, even a smooth looking rock, is a solid. It has a pebbly texture. Rocks are primarily minerals that become forced together over time. They end up grainy and gritty.

As water covers the rock’s surface, the water fills in all those microscopic and visual-to-the-eyeball nooks and crannies. This touching of the rock to the water creates a wet smooth surface on the rock where the liquid and the solid meet.

How do we visually interpret what’s going on with water and the rock?

We see via our brains interpreting light bouncing off surfaces. When the light bounces off the wet surface with all the divots of the rock’s surface filled with water, there are many more teeny angles in the divots to reflect light. The rock reflects more light and appears brighter and more colorful.

Naturally, there are stages to this. As the rock dries, fewer nooks are filled with water so the reflections are tamped down, and the rock appears damp, not wet.

What are other ways to "see" water?

As we paint and create the illusion of rocks in water, we need to use all the visual cues available to suggest to the brain what it is looking at.

Photo by Diane Goode. Posted on Facebook.
Used with permission. All rights reserved.

In my opinion, this is a photo of an almost unpaintable water scene. You can see the surface of the water, see through the water, see the fish swimming in the water, see shadows on top of the water, see the vegetation growing from the bottom of the water, etc. It's one of my favorite photos--it's gorgeous. But it would be a real challenge to paint in watercolor. It would be difficult to create this ethereal, believable scene featuring so many of the qualities of bodies of water.

If the water is murky and especially if it is not moving, we need other ways to convey wetness.

Here is a not-so-beautiful photo. It is another one that pokes at me about how difficult it would be to paint.

This stream is very shallow. It is the end of August in Cleveland, so it is muddy and almost dried up. It has a lot of shale rock in it, so the rocks are flat and "laminated." There are places. especially on the rounder rocks, that you can see the water has pushed up on the rocks. There you can see they are wet. Those clues inform you that this is a photo of water.

As you look at this photo, recognize how your eyes continue to scan across the image looking for additional clues. Your brain is attempting to interpret this ambiguous image.

In the cropped photo below, I have highlighted the big flat rock on the upper right. If you hadn't see the rest of the photo--if you saw this image in isolation, I don't think you would be able to tell that the dark brown color is water, and that the blue-gray-white shape is dry rock.

If this were your only reference, could you tell that this was a flat rock in a stream-bed?

It's often more challenging than we realize to discern water or specifically the surface of the water.

A few ways we perceive water

As shown above, when our eyes continues to examine a photo to look for cues, we look for certain characteristics in the scene. We attempt to identify:

• What is floating on it (pollen, leaves).
  
  
• What is slicing through it (sticks hanging from a tree into the water, vegetation growing from the bottom through the top of the water).

This is my photo of lily pads in a rainstorm. The rain has temporarily submerged most of the lily pads. We can see them under the surface, yet some are starting to pop above the surface. This is another difficult photo to interpret. What is going on in this limited context? Especially if you don't recognize the lily pads as an aquatic plant, I'm not sure what you would think this is. Jane M. Mason (c)

• What is in it (fish-egg-masses suspended in it, vegetative matter that is a dense as water, so it floats midway between top and bottom, fish swimming through).
  
  
• What is on the bottom below it (sand, rocks).
  
  
• If we perceive due to the movement in it (ripples, waves, vortexes or whirlpools, water spouts).

The indication of movement as indicated by the white horizontal lines and the slight darkening as it passes over the rocks, tells us that it is water.
A watercolor sketch by Jane M. Mason, (c).

Waves at Rockport. A watercolor painting by Jane M. Mason, (c).
In a private collection. Let me know if you would be interested in this image as an 6" x 8" print.

• If there is a meniscus ring or a white edge against a stable object (rock tree, building)

Notice the narrow white edge on the front of the rocks. The white in the distance at the horizon also suggests this is a body of water. That is presumably a row of waves or an area that is lit by a streak of moonlight. This was a stormy day at dusk when I painted this in County Kerry, Ireland. Jane M. Mason (c) In a private collection. This image is available as a note card. ​

This is a photo by Christophe Meneboeuf available on Wikipedia through Creative Commons. I believe it is the same lake just a different view. In this photo you can see the clouds reflected which tells you it is a body of water, and again, the telltale white line at the horizon.

• If a shadow falls through it, or where a shadow remains on the surface of it.
• If there is a reflection on top of it.

The orange color in the watercolor wash indicates that the mass is water and is reflecting the orange tree.
A watercolor painting by Jane M. Mason (c)

Can you think of other clues to help identify a body of water?

What is the “right” color for water?

We think of water as being primarily shades and varieties of blues.

This is a work in progress based on a painting by Edward Henry Potthast. Notice I have added a very light layer of blue to most of the sand around the girl with the toddler in her arms and the dog. Soon I will add sand-colored paint on top of the blue in those areas. My goal is to have the sand look very wet--almost saturated with water. But if I mixed the sand color with the blue it would turn green. So I am adding it in layers. One dry layer on another. The water at the horizon line will look much deeper and active than the water in this shallow area at the front of the painting. This painting will be available on my website when completed. Let me know if you are interested and I will let you know when ready and priced.

Yet, as far as I can imagine, water can be any color depending on time of day, time of year, available light, condition of the atmosphere, and the condition of the water. And, if you are the artist, it can depend on your imagination! :-)

Very clear water although it looks green. The bottom os the lake is green. You can see the fish swimming in the water and the sparkly reflections of the sun on the bottom of the lake.
Photo by Jane M. Mason (c)

And, we haven't even begun to talk about water at sunrise, or sunset. Or water in the rivers in Chicago on St. Patrick's Day! It’s crazy when you really ponder all the possibilities.

It seemed so simple, right?

Some of my artwork featuring water

• ​Petite Flowering Trees in the Spring
  A small rug hooked landscape featuring trees bursting with the luscious blooms of spring. The trees are reflected in the water on a clear spring day. This piece was created via rug hooking, and includes wool strips and wool yarn. It was hooked on a piece of linen.
  
  
• ​Petite Brambles at the Shores
  A hooked rug landscape with a jaunty cloudy sky, water in motion, and a dense area of bramble and shrubs at the edge of the water. the bramble could include blueberry bushes or lilacs. Or, what do you imagine it includes? 
  
  
• ​Birds Eye View: Tide with Birds Chicago Skyline
  Contemporary view of Chicago skyline. Small embroidered collage with recycled and upcycled, found fabrics. A quilt backing supports a tea bag stained with rust from rusty tools and chains, as well as lace remnants, pages from a vintage dictionary, and pieces of silk ties.

A couple of my greeting cards featuring details from nature

• ​Butterflies and Zinnias
  A greeting card with a quote about love from Maya Angelou.
  
  
• Mother is a Word for Love
  A greeting card created from my original watercolor painting featuring a rural scene with a farmhouse and a windy, cloudy sky.