Hi Diane
Welcome to the forum. I am sure you will enjoy the great community we have here.
Lots of questions in your post!
You ask what I mean by: "in order to have form, you must change the color temperature. What does this mean?"
What I mean is that you can describe form by using colour temperature. This is a cylinder. You can make it look like a flat plain if you paint it with one colour temperature. But by making one side warm and one side cool - you will create the appearance of a rounded cylinder.
The same goes for a ball, a peach, a face, and arm - everything that is not flat.
Question:
If my local color is warm, then my shadows should be cool and vice versa?
Answer:
This is not always the case. A typical outside light would be cool and the shadows warm. Inside (when not affected by natural light through a window) - a typical lighting would be warm and the shadows cool.
There are exceptions - but this is generally how it is
Question:
How would you use this idea when doing folds and ruffles, portraying concave & convex items?
Answer:
You simply place warm against cool and cool next to warm.
Look at my painting below. Can you see the ruffles in the edges of the rhododendron? You can see I have used line, tone and I have also used warm against cool to describe the ruffle.
Question:
Where do you place your strokes (in folds and ruffles) and how do you stroke - is it supposed to be all the same value or a graduated value? In what direction should the stroke be?
Answer:
I always stroke in the direction of the fold in the fabric
You will have seen my priming method in my dvd. This is what you do. You lay in your colours into the primed paper. Ensure you prime outside the areas you wish to paint though - as well as where you want the paint to be. This way you will get a soft graduated edge rather than a hard edge. Hard edges are used to describe sharp edges - not rolls of fabric
It is the same when you want to paint a petal that has undulations as below. Check out the images in the gallery of my new website
http://www.susanart.comYou will see how I have painted many dresses and skirts using this method.
You will also see many of these things in the flowers etc on my dvds.
Hope that helps
Susan