How do I colour my animation

After I have done drawing my animation, then I'll have to color it. I use Photoshop to color most of my animation.
First of all, I have to scan in the original animation I have done.
Here are some example of my animation, they were all hand drawn by myself, with blue or red pencil.


Then I'll have to open the images in Photoshop, and bring the contrast higher
Most of my classmates will clean up their animation, by using tracing paper on their animation, and then use black pen to draw over it, so their animation can looks nice and tidy. But I've chosen not to do my animation in that way, because I always like to keep those sketch lines and it can save a lot of time. This is really my style to works.


A higher contrast level will be easier for me to use Magic wand tool to cut out the images


After I've cut out the images I need then I'll have too save it as PNG format, the following images are the PNG versions.


Then I open all of the images in photoshop, but in different layers.

Then Use Hue/ Saturation option to make it black and white, that will be much more easier to color.(Now I think the sketching lines look nice when I turned the images into black and white)


Then I started to paint the images with different layer as well, in term of the face, hair, clothes, and hands. (with about 70% to 90% of Opacity and fills)


Then when I am done with coloring one image, I go to the next one, drag the layer of the colored face, hair, clothes on the top of the second images. Then I can adjust the size or edit a bit of the color layer to fit on the second image, so I wouldn't have to spent time painting a whole new image again.


The following images are done with coloring.


And here are a sequence of this colored animation.