To me Color is the written sheet music, Shading is your ability to color the music. Music to me is like a child's coloring in book. You see it, it is blank, has no color, just the outline of the picture which you have to get your pencils and color in. So color to me is like the empty pictures in a childs coloring in book, you can see what it is, but you have no concept as to what choice of shading to use. Shading then to me, is your ability to control the structure of the music, how well you actually color in the picture. Color is the genius stroke of composers writing, it is the skills of the composers which bound all choice of notes/rhythm together. We can't effect color(the empty picture), that is always there, what we must do is shade it all right, or it looks like a kids book with untidy coloring in, going outside lines, using wrong colors, mixing them up etc.
Color and Shading to me seems to be simply the sound control of notes, the expression. It has nothing to do with accuracy of notes, people can play very inaccurately but have wonderful color and shading (even though wrong notes take away from the sounds overall effect it doesn't totally destroy it, that is why in exams some teachers are kinder than others when note mistakes are done, beacuse they can see through that and still sense the expressive nature of your playing, but some cant so they fail you.)
The progression of chords generates infinite ideas. For instance, play a C major then a C minor, we all know the minor of course naturally has the more "sad" sound than the C major, the color is set, major to minor will alway create a happy to sadder feel. Think of its shadings now, if we play the Cmaj soft then slam out the minor, that shades the idea differently than Cmaj very loud to a soft Cmin. If we finish loudly then we think, oh it must continue, the color of the loud Cmin demands that it is connected to more. But if it is very quiet and controlled then it seems to be a resting point. If the Cmaj is soft it sounds like an ending, then if the Cmin is loud then it sounds like we are starting a new group of notes but in the minor. The color is happy to a sad (like bright yellow to dark purple lol something like that), but the shading depends on the movement of the music. How do you shade it? Are the colors just juxtaposed next to one another, or are they blended, smudged? Do you just play them both the same volume? Is one louder than the other, is one shorter in sound than the other etc etc. All these things effect the movement between two chords.
From Cmaj to Cmin we could have quite a few different varitiaions of rhythm, added notes inbetween each, volume or touch quality(stacatto, legato, marcato etc) each of which has a reason(connect, introduce parts of the piece etc), you must understand those reasons if you want to crack how to present the color/shading.
How well you construct/present musical ideas is color and shading. What do I mean by constructing color and shade? Well if you come up to a cresendo for instance, do you just get louder on the overall group of notes or do you select notes which gradually pull the sound louder and louder? This would make your control of the cresendo a lot more intimate and focued. You see this is the best way to discover shading and color of music in my opinion, break expressive ideas of the bar(s) into partilcular notes which effect the change most, and play in a stepwise fashion each one note which alters the sound. Then you go back and make these sharp stepwise alterations into a more smoother curve progresion. That to me is controlling the color/shade of music, knowing how to make your progressions move smooth like a curve not stepwise, and knowing when to make it very sharp and stepwise (immediant tempo/volume alterations etc).
Moving to a cresendo for instance. You can shade it in very routine, just get a little louder, or you can shade it more detailed with more contrast in sound, start a lot softer than you usually would and get a lot louder. That increases the length and bounds of your expression (color and shading), also choosing which few notes draw the sound louder and making the progression between each intimately felt (feeling and observing the shape that the notes which effect the sound stepwise make) will increase your color/shading ability. Of course we cant play ppp to fff on every cresendo that is ridiculous, that is where we must make the musical desicion as to what is best, and that is what makes us all unique in our playing.
That also comes up, what is f for you is maybe mf for others, maybe your pp touch is someone elses f touch, although the latter would require one person to have playing problems. f and mf are good examples, where does one find the common point where the volumes comes from? A lot of music when i play is much more naturally heard, i dont think ok this is loud lets play louder coming from my arm. no, its more automatic. But i think that it is first important to have a concept of where all the volumes physically come from. I wrote this before here:
https://pianoforum.net/smf/index.php/topic,7150.msg71298.html#msg71298I guess what i try to say is that we need some common tools used for our color, or maybe music is so various that we all shade the color in with constantly unique tools. I dont think so, i feel that we all must have some common ground and then the variation of that is our personality.