Tools for evaluating light and color.....I keep a color wheel and a value finder with my rug hooking tools and find them to be invaluable. I have another color wheel that I keep tacked up next to my dye cabinet. It gets used constantly!
Sometimes I use the "squint" method for evaluating value but my favorite tool for evaluating values is my camera. I take a photograph of the area in question & convert it to black & white. It's easy to see at a glance when a value needs changing.
In this value study, I can see immediately in the B & W photo that I might want to change the value of the gold in the window pane of the blue door. The values of the gold & blue are almost the same & the pane disappears. In this particular case I probably won't change it because I like the overall quiet and cozy feel of the little cabin so far.
As you can see, it's a little slow-going on Wonderland right now.....I've worked very hard at getting the trees to stand out and I've mades several small changes to the rooflines to (hopefully!) give them some dimension.