setting things up

All this starts with a finished image, one you have done all the shadows and highlites and it is "ready".

In this case the image on the left is the one ready ... but i HATE the fact that colors dont seem to be set in night time, specially on her skin x.x. Plus all her clothes are in grays shades ... they should be more into blue shades.

I want all colors to match even more than what i have dont so far.

So, first i will create a new layer, this layer will be on top of ALL OTHERS!!!

since i want all colors to merge better in my pic, of course it will need to be on top ... simple common sense.

So go to your layer Window > Layer > Create Standard Layer

Now, this is what i got. A new Standard layer set to 100% opacity ... Repeat with me, calculation and opacity are my friends...

In a way, knowing what a layer calculation (or layer mode in photoshop) does is the holy grail of coloring. It will save you a lot of time and you will be able to create stuff that maybe havent even crossed your mind before.

Choose your tint

Now, choose your fill tool in your tool window (K in opencanvas, G in photoshop)

This time i will use one plain color for this image, however you can choose 2 or more colors. Pretty violet blue in my case

Now, fill in that top layer you created not long ago!

Yes, the top one! dont fuck up any other layer. Thats the point of creating a new one, right? >_>

So far all you will see is all blue, this is OK because our layer was set to standard at 100% opacity, but now that will change

Color calculation

Now you will change the layer calculation.

On your layer window click where it says Standard. A drop down menu will appear, all those are layer calculations choose COLOR. It will look terrible at first, but thats ok.

Each calculation will have a different way to render what you have drawn. In our case we will use the COLOR one.

What does it do? well, it renders the lower layers with a blue tint (or any color we have in that layer) and if there is an empty space in our color layer it means the lower layers wont be affected by any color, displaying what you had so far without any change.

See, this is what i mean by "it will look terrible at first"

We have a color layer, but this one is set to 100% opacity, making everything beneath it look into pure blue shades.

So the obvious thing is to change that opacity to the one you like or best fits your image.

Opacity

When you scroll that little horizontal bar the opacity of the layer will change.

In my case, and in more of my pics, somewhere around 30% and 6% works for me.

Opacity set to 23% this time.

Check it out

before and after images on the right

Note how the colors match each other more now, this is my personal taste

another example

I posted this one in some other tutorial. This one is the original images WITHOUT the color layer for matching colors.

If you fill it in with a cool color like blue you get a cool feeling.

check this out