Before reading this, make sure you've read the other tutorials on basic coloring and masks
If you're like me, you're always looking for new ways to make your computer colored images more realistic. Sure, we can draw our characters well... but what about adding shadows and highlights that the "cool" artists do?
Now, you're gonna hear it straight from me: I'm no expert at this. At all. I generally try to avoid sitting in front of the computer as much as possible when it comes to working on images. But I have sat for hours looking up how to effectively and quickly apply shadows and lighting to my colored works. I've read tutorials and looked at forums and pretty much banged my head against various blunt objects. The ways I found were indeed helpful and easy if you are patient and a professional. But I'll be damned if I didn't find a thousand and one ways to do it in some of the most pain staking ways?
Some people say "use the eyedropper to select the color you want to shade, open up the color menu, and choose a darker/lighter value for that color." ...That is aggravating. What if you have a lot of colors in your drawing? HOW TEDIOUS!
Other people say "make a multiply layer and add a dark shade of blue. On another layer, use white for highlights." ...Uhm... Blue doesn't always work. And if it does, it would help if you gave use the proper RGB values to boot. Also, light isn't pure white: it is a mixture of various colors found in light. Unless you're characters are being photographed with a camera with flash on, this doesn't depict reality and professionals will be quick to pick this out."
The response I hate the most... "Take your tablet and..." Not everyone has a tablet. Some people don't seem to realize this. If you have a tablet, good for you (...actually, I do, but it's not working at the moment ^^;;). I highly suggest you get comfortable with a mouse first. Cuz what about the day someone wants to see you work and they set you down in front of a computer with Photoshop AND NO TABLET? Are you gonna turn to them and say "...I can't work without my tablet?" They are gonna look at you like you're spoiled to the core.
Anyway, so after doing some research and mixing some of what I've learned, I am going to share with you a technique (no, I did not invent it) using layers and masking them to make your shading and lighting easier for you.
First, select your image. Now, Blue Zombie was meant to be a webcomic. With that, it has a certain style. I personally don't like seeing BZ trying to mimic reality too much, so I'm using an non-Blue Zombie image for this tutorial. Again, I am using GIMP on a Linux machine (which is going to change soon). However, the same technique will get you similar results in Photoshop, Paint Shop Pro, Dog Waffle, or GIMP on any PC or Mac.
The image I have selected:
Now, I've added base colors (covered previously in the coloring tutorial). Please note that I colored all of Lula's skin, hair, clothes, and bandages on one layer and then I colored her spell effects on another separate layer. The image now looks like this:
Here's a snapshot of the layers:
Now, we make a duplicate of the base color layer first.
This going to be our shading layer. Never apply shading or highlights to the same layer as your base color layer.
In reality, shadows occur where there is less light availabe on a certain part of an object. So, theoretically (or, in other words, "in my biased opinion") the color of the light is not going to have too much of an effect on the shadows. Also note that shadows are not entirely black. Now, with this layer, we can do a number of adjustments to change the value of the color. I personally start with adjusting the brightness of the layer via "Brightness and Contrast". I do not touch the contrast. Instead, I bring the brightness down. Depending on how dark you want your shadows--and let me say, if you want a very good range, make them very very very dark--you may have to adjust the brightness several times over to get the desired effect.
After that, I usually go into the "Color Balance" menu and mess around with it, just to give the shadows some color. I've made them a little blue, but not too much.
Now, our image looks like this (note that because they are on a separate layer above this one, the colors of the spell effects haven't changed):
To create highlights, we do something similar. We again duplicate the base color layer. Again, adjust the layer to alter the color however you please. I brightened it a bit, then gave it a yellow tint by adjusting the color balance. Depending on your preference, the order of which your layers are organized will vary. I tend to put my highlight layer on top of my shadows layer.
Our lighting layer looks like this:
Notice something? That's right, Lula's bandages aren't affected. That's because I made a mistake! I made the bandages pure white! In my opinion, it's not very wise to use pure white or pure black on your base color layer. This slipped my mind. Anyway, because of how computers work, the color white is the maximum value of all three colors (red, green, and blue) together. You can't make it brighter. Also, in this case, trying to adjust the color to a yellow tint has had no effect on it because it is already pushed to the greatest values available.
I'm too lazy to go back and fix this :P
Anyway, we not only have this generic, yellow tinted light to worry about. We also have the light from the spells Lula is casting. So, again, make another duplicate of the color layer. This time, adjust it so it has a magenta tint. AND... we are also going to go in and airbrush the hand that is casting the spell. This will sort of guarantee some sort of reflection off of the bandages since they are white.
We do the same with the other spell: duplicate, adjust it to look cyan. Color the apropriate bandage as well:
SO... we have one shadow layer and THREE lighting layers! And it didn't even take that long. But all we have right now are four, seemingly useless layers that have had their colors adjusted. Now what do we do?
Enter the layer masks. If you haven't heard of a mask, please go back and read my explaination on them. That's right, we are going to apply a layer mask to each of the four layers! But first, a warning: though a layer mask can alter the appearance of a layer (in other words, determine which pixels are transparent and which are opaque), they do NOT alter the actual layer. In fact, if you are not careful, you can accidentally select a layer instead of its mask and end up drawing on that layer! To avoid this from happening, be sure to select the mask (which will have a highlight around it) and not the layer.
Here's a picture of what your layer menu (I renamed my layers) might look like with masks:
Notice the black square next to each layer. That's the mask. In a mask, you have your opaque color (white) and your transparent color (black). Using white allows the pixels in the layer to become opaque. Using black makes them transparent. Pixels can even be partially transparent on a layer mask by using any shade of gray. This is helpful because if you make a mistake with the shading, instead of throwing away the layer, you can switch between the two colors and correct your mistake! Heck, if you find that your layer isn't dark/light/tinted enough, you can select the layer and adjust it. The adjustments on the layer itself won't affect the masks at all, just like adjustments on the mask won't affect the layer (just it's appearance). Since my masks are black, that means the pixels are all transparent at the moment, so you can't see the layer, even though it's there and the layer itself is set to 100% opacity. This way, I can "add" the shadows and highlights using the airbrush and the color white. You can set it so that the layer mask is white, making the layer opaque, and then "subtract" from it using black.
I use an airbrush with very low opacity for this. What methods you use for the masks are up to you. Your only color choice, however, is restricted to white, black, and any value of grey in between. You could use a select tool to select out the areas you want highlighted or shaded and then fill them with white.
During the process, it is a good idea not to focus on one layer mask at a time. Instead, actively switch between layers masks so you know how they affect one another's appearance. Tweaking one layer mask might dramatically affect the outcome of the entire image. It's also a good idea to take breaks and come back to the image. If you refresh your eyes from time to time, you will catch mistakes or maybe something you want to change. If you do it all in one sitting, you're likely to get so focused on the image that you may miss something. Also, save often.
Alright, I'm all finished. Here's the breakdown:
I've taken the layers and broken them up from bottom to top to show what I did. First, the shadow layer. I used the mask to push back receeding folds in the clothing and anything that was being overshadowed. Somewhere in between, I decided that the shadows should be darker to get a better value range, so I went back and adjusted the layer some more. This is what the shading looks like:
Next up is the first lighting layer. For this, I decided to go more for rim lighting, so I mostly applied it around the Lula's edges. I did apply it in other spots where I thought it was needed. Combined with the shading, I got the following results:
Next up, the light from the spell on Lula's right hand. Since this light is only in one area and not too intense, I only needed to apply the airbrush to a small area on the layer mask, mostly around her face:
Next, the light from the other spell on the left hand. Again, I only applied it to some of the mask, on the Lula's lower left side.
We're within the home stretch. I make the spell layer visible again so as to see all of Lula.
Looks interesting! Yes! But we aren't finished. I mean, for goodness sake, we are not implying the direction of the light surrounding Lula! She's just floating in mid air in pure white! If we want to get a much more dramatic effect, we need to add a background. Even a simple one, so as just to capture the idea of how her surroundings are lit. So, I took the liberty of using a gradient for a background. NOW... we are done.
Lula looks really pissed off. Maybe we should get outta here...
Anyway, I really hope this helped you guys out and made it easier for you to use lighting and shadows. The above image is only a demonstration of what you can do. I was able to do it all in about 2 our 3 hours. Imagine what YOU can do if you actually put TIME into it!
This is Esrix, signing off.