This is my first time writing a tutorial so bear with me I know I'm not the best teacher around but I tried.... *dies*

Anyway, this is a mini tutorial (actually, I'm not even sure this is a proper tutorial or not... I'm just recording what I've done in order to create a piece...) to show you how I do Cel Shading in Open Canvas 3.03.



Step 1
Make a sketch!!! As my scanner is too old, my new computer doesn't support it... So I tend to do my sketches directly in Open Canvas. This is not recommended unless you have a tablet!!! (or you're extremely good at drawing with a mouse) It doesn't really matter what size brush you draw in, I usually work with the default setting.


Step 2
As I'm not very confident with my tablet drawing skills, I tend to "ink" my drawing on a seperate layer. So open up a new layer (Calucation = Standard) on top of your "sketch" layer. To make it easier to see your "ink" line, lower the opacity of your "sketch" layer first. I suggest around 20 - 30%. Start inking on the "Ink" layer (again, it's all up to personally preference as to what brush size you want to ink in... I always go with default setting, you can always make your line thicker by going over it several times). As to how to ink clean and neatly, I'm afraid you just have to be patient and practise a lot. I usually zoom in to 150% when I ink, because I found it easier to get clean lines that way

Out of habit, I like to use several layers when I ink - 1 layer for hair, 1 layer for the face + hands etc and 1 layer for clothes. I do that because it's easier to do individual adjustments when needed to. Especially concerning hair and facial features. As hair are always made up of long curves, it is likely that you would ended up with curve that's made up of lots of straight lines when you ink. This is when the seperate layer comes in handy. Inking hair on a seperate layer from the facial features allows you to clean up the hair ink lines without erasing the ink lines for the facial features, vice versa. You can always merge the layers (Layers > Merge Down) when you have finish inking. (you can also delete the "sketch" layer when you have complete the inking process)


Step 3
This is a point of deviation.... you can choose to colour in the background first or colour in your character first.... In this example, I colour in the character first (my bad )

Anyway, open up a new layer (Calculation = Standard), move this layer to BELOW your "ink" layer (or layers) Start filling in the "base" colour (by "base" colour I mean just one block of colour with no variation of tone in i.e. no shadow/highlight) Again, I personally like to use several layers for this. In this example, I used 1 layer for hair, 1 layer for skin + eyes, 1 layer for the cloak and another for the clothes underneath. That way it's easier to make individual adjustments on the colours when needed to.

For those without tablet, you can use the Polygonal Lasso tool (circled in the screenshot) to map out the area you want a particular colour in, then just use the paint bucket to fill in the selected area. For those with tablet, I suggest you not to use the Watercolour/Airbrush tool when you fill in the base colours, use the Pen/Pencil tool at 100% opacity instead. You may still have to go over the area you have painted several times to get the 100% opacity.

The reason for using Pen/Pencil tool instead of Watercolour/Airbrush tool is that Pen/Pencil tool are a lot "firmer". For Watercolour tool, you have to run over the same area a lot of times before you can get to 100% opacity. Same goes for Airbrush tool and on top of that, Airbrush tool has a blurry edge to it (which is something you may not want when trying to paint in Cel Shading style)


Step 4
Open up a new layer(Calculation = Multiply) on top of the "base colour" layer (or layers) but below the "ink" layer. This new layer would be use for shadows. Define your light source then start adding in the shadow accordingly (sorry I don't know how to teach people how to do this, apart from do a lot of observation) Again, use the Pen/Pencil tool at 100% opacity not Watercolour/Airbrush tool (or Polygonal Lasso tool if you prefer).

After you've completed the "shadow" layer, add a new layer (Calculation = Addition) on top of it for highlights. Again, use the Pen/Pencil tool!

Step 5
Add a layer (Calculation = Standard) below the "base colour" layer and use it for background. In this example I just filled the layer with a single colour and painted a bit of blood splattered on it.



This is basically it. In this example I added another layer on top of all the layers and painted some blood splattered on.... My way of doing this gives me a lot of flexibility because I can adjust the colour/brightness of a lot of things individually (as I'm hopeless when it comes to picking colours...) Hope this helps answering the question as to how I paint in Cel Shading style in Open Canvas


EDIT: This method also works for Photoshop and Painter too. Just that in Photoshop it doesn't have the layer option known as "Addition" (at least, I don't think it has), so for the highlight layer, you can use other layer option such as "Screen" or "Colour Dodge" instead.