As someone who does a lot of creative writing, I find that having a visual aid is immensely useful to help inspire ideas. It gives substance to a character that was only an idea. One of the best sources for character 'bases' is from anime and manga, because the detail and character design is on another level compared to anything else that I have encountered. However, sometimes a base just isn't right "enough" for your needs. This is where character edits come in.
The base I am using is Megurine Luka, and I am changing her to match the likeness of a character from one of my stories. My character has red hair, green eyes, and wears a blue and gold dress. The program I am going to use is Gimp 2.8, which is a free image editing tool which I actually prefer over photoshop for this kind of work.
Step 1: Load Your Picture
It is as simple as starting gimp, and dragging and dropping the image you want to edit onto the program. This image can be from anywhere.
Step 2: Begin Selections
I always start with the hair, personally.
In this step, we will be using the Free Select Tool, its icon looks like a lasso. This is the most important tool in the gimp toolbox, so it is useful to become very familiar with it. It works by encapsulating the area that you want to be changed with points that are created wherever the left mouse button is clicked. These points can be moved around freely, and the last point placed can be removed by pressing backspace. If desired, the left mouse button can be held down to create a free-style line to encapsulate an area. Once you are finished placing your points, double-clicking joins the first and last points together.
An important note to add is that there are 4 different modes that the Free Select Tool operates in; Replace, Add, Subtract, and Intersect. In most cases you want to use the Add mode, which is signified by two overlapping red squares in the Free Select Tool's option pane. If there is any part of your selection that you want to remove, select the Subtract option that is immediately to the right of the Add option.
Once you have all of the hair selected, move on to the next step.
Step 3: Creating a New Layer
Layers are your best friend, they will save you from nightmares, pain and anguish, and probably carpal-tunnel.
In the Layers dropdown, create a new Layer. Always name your layers.
After this, click the Paintbrush Tool, and select your desired color. I chose red for my example, because that is this character's hair color. After you select your color, make sure to increase the brush size to save time and to get a more complete coverage of your selection.
Step 4: Fill in the Blank
The person who taught me to do this always said that this was her favorite part.
Once you have your brush set up, make sure you have the new layer selected by clicking on it on the right side of the screen. Fill in the selection by clicking in the picture and dragging your mouse around madly until your entire selection is filled. Once you have finished entertaining yourself with this, look over at the top right of the screen at the Layer Mode option. This is a drop-down with several options about how the layer is applied to the image. A useful trick is that you can use your mouse-wheel to scroll through the options and find the one that you prefer.
For this character, the exact color of her hair is important, so I chose to use the Color mode.
This looks pretty good, but it is a bit too washed out for my taste, so lets add some substance.
Step 5: Adding Substance
If you ever lose your selection, it can be a huge pain to try and redo it. Luckily, there is a simple solution if you have already filled it in with color. Right clicking on a Layer and clicking "Alpha to Selection" allows you to get back what you have already filled in.
Now, to adding substance. To do this, we are going to create a new layer called "Hair_Burn." You follow very similar procedures as adding the color, but this layer is applied differently and therefore has a few extra steps.
First off, we need to select a light grey color instead of our red. Also, it is very important to make sure that the "Hair_Burn" layer is beneath the "Hair" layer. Once this is set up, your just do your favorite activity and fill in the selection with the grey.
Now, the first thing you will notice is that her hair is a flat shade of some kind of murky pepto-bismol. This is okay, because our layer mode is set to "Normal," which means it is just a flat color. We want to set this to "Burn," and everything immediately becomes clear. The Burn mode essentially darkens the dark areas, while keeping the light areas relatively the same. This adds a lot of contrast, without losing detail.
With that, her hair is complete.
Step 6: Look Into Her Eyes.
Now we go to her eyes.
This is pretty much the same as what we have been doing for a while now, so you should be able to get the picture. No pun intended.
Select the area of her eyes, create a new layer, name the layer, choose a color with the brush tool, fill it in.
My personal preference for doing eyes is to use the Hue layer mode. This maintains any saturation and value that the colors have, and only alters the specific hue. This can get rid of some fine detail, but creates the most realistic looking eyes in my opinion. However, eyes are very flexible, and I recommend experimenting with different layer modes to see what suits you the best.
Step 7: Additional Details
You can repeat this process as many times as you would like, to get the character you want. For example, this character typically has dark, reddish iron colored nails. You could change anything, from the flowers to her skin color, although skin color takes a special talent and a lot of trial and error to get perfect.
Step 8: The Flowing Dress
Clothes can be tricky, because they have different kinds of textures and reflect light differently. One of the key parts of this is to decide which texture you think it is, and stick with it.
For this character, I believe her dress is a kind of silk, so it is less reflective, matte bright colors, and has detailed dark colors.
I chose a dark ocean blue and applied it using a Color mode on a new layer. This was close, but was too bright and cartoonish for my taste. I instead chose to switch it to Overlay mode and decrease this layer's opacity, allowing some of the original, darker dress to show through.
Step 9: Save and Export
Once you are happy with your image, save the .xcf file where ever you would like, and then go to File > Export. This will give you the option of creating the image itself, in most major file formats. I prefer .png files because they do not sacrifice as much quality, and have transparency support. I also always lower the compression to 0, so the image is the highest quality that I can make it. I have found that this is a good tradeoff between filesize and desired quality.
Step 10: Enjoy Your Image!
Have fun with your image! I create these to help me get inspired to write, but the tools used in this can be used for many other images.