Why Bother with Custom Portraits?
If you've played Neverwinter Nights beyond simply taking a run through the single-player original campaign, chances are you've wished for a wider variety of character portraits to choose from at some point. I found the portraits provided with the game to be, in many cases, inappropriate for the characters I wished to create, for various reasons (age, hair color, clothing, etc.). What to do about this?
There are two options for you here. Either you can go to one of several websites and download a fan-created portrait (there are thousands of portraits to choose from, varying in quality from hilariously amateur to dazzlingly professional), or you can draw your own. If you find what you are looking for among the fan-created portraits, then you're all set. However, certain types of portraits are few and far between: not many people draw halflings, or male characters, or people of color, or children. The majority of portraits out there seem to be pale, slender (yet amply chested) females.
If you've decided that you want to draw your own portrait, you may be quite intimidated by the existing artwork out there. The official Bioware artists, and graphic artists working on other RPGs often post their work for free download, so you will certainly run across some portraits that will make your eyes bleed with their glory. It can be a humbling experience. There is no reason to be discouraged, though...all you really need to create a serviceable portrait is an image manipulation program such as GIMP or Photoshop. I am quite enamored with GIMP, since it is free.
Technical Considerations and Requirements
The primary requirement of the graphics program you use is that it must support the Targa, or .tga format. This is the format used by Bioware, and no portraits in any other format will work in the game. It is also critical that when you save your image, you save it as an UNCOMPRESSED .tga image. In GIMP, the default option is to compress the image (there is a check box that you need to unselect in order to turn the compression off; it will come up in a dialog when you try to save). The effect of using a compressed .tga image is that you will be able to start a game with the character portrait you choose, and you will be able to save this game, but you will NOT be able to load any games later on without crashing the entire program. I went through several painful hours trying to figure out why I couldn't load my games, before I realized that it might be due to some property of the custom portraits I was making. Luckily, the error was easily fixed by reopening my images and saving them again without the compression option.
When creating a new image, start with a canvas size of 256x512 pixels. Your portrait itself will take up 256x400 pixels. The bottom 256x112 pixels will not be seen in-game, so you can put anything you want here...many people like to credit themselves in this region with a logo or signature; I usually just leave it blank.
A complete Neverwinter Nights portrait actually consists of five images, each a different size. Once you have drawn the largest image (the "huge" one), it is quite simple to create the smaller ones by scaling the image progressively and saving at each step. You can call your image anything you want; let's use "elfboy" here, assuming we are drawing a young male elf. The following steps must be followed to create a usable portrait:
1.) Save the 256x512 image as elfboy_h.tga. (h = huge)
2.) Scale the image (not the canvas!) to 128x256 pixels.
3.) Save the 128x256 image as elfboy_l.tga. (l = large)
4.) Scale the image to 64x128 pixels.
5.) Save the 64x128 image as elfboy_m.tga. (m = medium)
6.) Scale the image to 32x64 pixels.
7.) Save the 32x64 image as elfboy_s.tga. (s = small
8.) Scale the image to 16x32 pixels.
9.) Save the 16x32 image as elfboy_t.tga. (t = tiny)
The scaling/saving process does not actually take very long; perhaps a minute or two. However, if you don't feel like doing all that, some people have written scripts for GIMP and other programs that will take your large image and create from it all the necessary smaller images. I don't bother with such things personally, but I'm notorious for doing things the long and hard way.
The Fun Stuff: Craft and Style
Okay, now you know the nuts and bolts of portrait creation. Following the steps above in the previous section, you could draw a stick figure and use that as your portrait, but chances are, you don't want to. The easiest thing to do is start with a photograph...this way you have the facial proportions and pose already available. However, some people prefer to scan their own pencil drawings rather than using a photo, while others use expensive figure modeling / posing software. There are a variety of options, and the path you choose is entirely up to you.
My personal technique is to start with a photograph of myself or someone I know. Some artists use pictures of celebrities (Allyson Hannigan, Catherine Zeta-Jones, and Angelina Jolie seem to be popular sources of Neverwinter portraits), but I prefer to use ordinary people. I am not sure what the legal ramifications are of using a celebrity's photograph without their permission, but I have not heard of anyone issuing complaints so far.
Start with any photo you like, but before turning it into a portrait you may wish to scale it to a size appropriate to the 256x400 restriction. The first experimental portraits I made looked funny in-game because they had too much background and not enough figure (I'd made the figure too small). Look at the in-game portraits for a sense of how big to make the figures...the most popular and easiest to see generally show about half the figure's body, with an emphasis on the head and torso. The head will normally go almost all the way up to the top of the image -- this leaves plenty of room to show a weapon or other accessory, and whatever clothing or armor your character happens to be wearing. Rarely, you will come across a full-body shot; however, I don't like these because I would rather see more detail in my character's face.
By far, the most appropriate way to deal with a figure in front of a background is to use layers...usually a foreground layer for the figure, and a background layer for the background. This way, you can alter these image components individually without, for example, accidentally smudging your character's hair into a tree branch. Nevertheless, I'm something of a featurephobe, and I tend to work on my portraits all on one layer, making judicious use of the freeform select tool. As always, it is up to you.
Most people prefer portraits that do not look exactly like photographs. To obtain a realistic yet artistic look, the paintover technique is often utilized. If you zoom in on a digital or scanned photograph, you will see that the subtle color gradients and shadows inherent in a picture of "real life" are made up of numerous pixels. The trick in making your picture look more like a painting is to reduce the number of colors in a given area. I like using the medicine dropper-like tool (that exists in most graphics software) to pick up a color from the image, and then painting a larger region of the image using only that color. This way, you get an effect that is more like paintbrush strokes than millions of tiny multicolored dots. I am also an admitted abuser of the smudge tool, and it can be very handy when smoothing lines on cheeks, jawbones, and eyebrows. To enhance the "painted" effect, some people also like to utilize filters. GIMP has numerous filters that I have never even tried, and it will probably take years to figure them all out. However, I am fond of the unsharp mask enhancement...it brightens and intensifies the image, as well as increasing contrast between adjoining color regions. If you try it on a normal, unadulterated photograph it will simply make everything look more intense and perhaps a bit more pixellated, but once you have done some painting and blending, the unsharp mask filter somehow manages to make the image look more artsy and painted.
A word about ears: if you want to make an elf, please, for the love of God and all that is holy, don't just smudge the tips on the ears of a human! This is extremely obvious and will detract from your portraits. Zoom in, draw tips on the ears, and blend appropriately. Sometimes you will end up redrawing the entire ear. This is okay. Your primary objective is to make the ear look like part of the figure's head, not a costume accessory.
For clothing, you can simply paint over whatever the model is wearing, or you can erase it all and basically create a new body for your figure's head. I generally end up trying to use as much of the existing clothing as I can, but at the end all that remains from the original is the placement of shadows indicating folds of cloth. Some people like to copy and paste bits and pieces of armor, etc., from other pictures. I have not done this yet but it seems to be a popular technique. Some sites have textures available for download that you might want to use for clothing and armor.
This little tutorial is meant only to offer the most basic information. There is really no substitute for looking at existing portraits and practicing (Save often! Save different versions of your work! Make sure you have a LONG "undo" queue!). If you enjoy drawing and gaming, you will probably find creating portraits to be very rewarding.
For those who are interested, a finished portrait by me can be found at:
http://nwvault.ign.com/Files/portraits/data/1071553104025.shtml
The base for the portrait was actually a picture of me at 5 years old.
References:
http://nwvault.ign.com
Personal experience, trial and error.