THIS. I cracked up so much DX
so I'm writing back from you in this thread to follow our conversation better ^^
Not at all ^^ I'm not much help..
In this case, we are the same. I determine a source of light but I get confused while shading and it ends up mixed ahah. With more recognizable shadow I mean darker shadow and add more shadow.
For example: This is how I shaded hair with the help of the tutorial I've posted before.
The dark purple shadow directly falls into my eyes. I don't have to search for it. The hair is also more detailed, means, more strokes. The shadow goes along these strokes. Shine is also easily noticable.
But please note that this only one of many ways how you can shade hair. ardrey for example does it completely different.
Hues are basically just color tones. Idk if you have that, but in Sai there's an option called "filter" which allows you to adjust colors on a layer. it can make it brighter, darker, more contrasting, a completely different color, more saturated etc. If possible, play with these options until you've found something nice.
Oh... well, then you'll have to deal with the tools you have there. Sorry I can't really tell you anything about air brush or smudge, I never use tools like this and I don't recommend them >-<
Isn't there a better program available for you?
Mmm. how can I explain these. I don't fully understand them either, but let's give it a shot.
For example, you have base color layer for the hair. above this layer, you create another layer clipped to the base layer (make a tick in "clipping group" if you have that). you create your shadows on the clipped layer. now you can play with the modes. the colors will change with every mode (sometimes not, idk). for example, the color changes, becomes brighter, darker etc. play also with the opacity (again, if you have that). as for me, this is mainly a playing & experimenting step. what I can tell you as some facts are for example:
lumiscence is often used for making light reflexes. for example, if you wanna add light reflexes to your hair, create another layer clipped above the shadow layer, put it into lumiscence mode and make your shines. these will appear really bright and shiny, based on the color on the layers below. for example, the base color or shadow color on the layer below is dark green. now you use the same dark green on the lumiscence-layer and the color will turn out real bright green.
shade or overlay are good for overeffecting, means, adding even more deeper shadow to make it more 3d-like.
I'll make ya a visual example! . . . . . .
VERSION without shade layer/without lumi&shade layer/without lumi&shade layer for the eyes.
http://i.imgur.com/Iloc9ku.png
VERSION with all these layers.
http://i.imgur.com/ARAcVZA.png
you can see now that there are pink light reflexes on the ears, white reflexes on the black kimono, dark brown shades on the ears and darker black shades on the kimono. the eyes have shiny details now too.
I'm so sorry I can't really explain you these layer modes either :c