Let's discuss purely technical details of icon creation
1. Lines, angles
One of the most important parts of the composition is the outline of the object, i.e. solid line, which separates the object from the background. When creating normal-sized graphics, the artist rarely cares about highlighting of objects with additional outlines. This is unnecessary because of the size: even low contrast objects do not blend into a single whole. Icon graphics is other story. Two variants are available: either foreground and background colors must be from different sides of the color wheel, or the object must be divided from the background by contrast outlines and shadows. I will dwell on lines in more detail.
If we think more to the large scale images, we can note that in order to highlight edges, we can use all (including the most complex) angles, Bezier splines and borders. In any case, the line will appear perfect thanks to anti-aliasing. When shrinking the image dimensions to the small icon size, situation changes dramatically. When each single pixel is vitally valuable and can ruin the whole appearance of the composition, anti-aliasing is simply not applicable. It means that you should think about the possible line slopes.
The slope you choose for the line, determines the step for this line. Because every line is made of primary elements, the combination of which determines its accuracy and esthetics.
For example, a 18-degree slope consists of many small 3-pixel lines connected using a 1-pixel downshift:
This is how nearly every line looks like. Basic element with joining and second basic element. Unfortunately, not each angle creates lines that look look neet and not annoying.
For example, here are 25 and 20-degree angles:
It can be easily seen which line is more appealing. The 25-degree angle makes a line consisting of equal 2-pixel basic elements. The 20-degree angle has a primary element consisting of three parts: 3-pixel, 3-pixel and 2-pixel. The angle is more complicated, thus, when not combined by other visual effects, it brings a feeling of messiness: the basic elements have contrast which is too obvious to escape the human eye.
Now we can see the first conclusion. The most "correct" angles must make as plain basic elements as they can. Thus, the ideal angles are 0 and 90 degrees. In those, 1-pixel basic elements are joined without any shift and form smooth lines. Less ideal are angles which form primary elements of 1, 2, 3 pixel with 1-pixel downshift. Of course, the lines can not be even, but the human sight will process the image and present to the user what you meant to show to him. Also, the following angles can be considered correct (but at a stretch): angles with primary elements consisting of different lines shifted by more than 1 pixel.
Now we can touch another issue. In the previous paragraph, I purposely defined angles with primary elements of 1, 2 and 3 pixels as acceptable. Such tiny lines, especially when a large amount of them is combined, appear as solid. But what happens if we increase the primary elements to 10 or 20 pixels?
Here is an example:
It can be obviously seen that the line loses its solidness. It is not a continuous line anymore; it is a set of different lines, situated near one another. Rarely any artist wants its composition to look inconsistent. So, we come to the second rule: if you use minimal slopes, which produse long primary elements, it has to be justified and employed with great caution.
And, finally, the third thing I have to tell about lines. I already wrote that the basic element should be as plain as it can.
For instance, a 25-degree slope can be drawn in the two (sure more of them are possible) following ways:
In the first case the primary element is a 2-pixel line. In the other case, it consists of three lines: 3-pixel, 2-pixel and 1-pixel. The same slope but the image is different. The complicated primary element produced the line untidy.
Such examples can be made for about any slope, so in your projects, make sure to simplify as much as possible.
It can be stated without an exaggeration that the color is the main element of your work; improper or poorly balanced colors can kill even the most creative idea. What can we say about the color in icon graphics?
First, there is a certain rule: if the picture looks bad when converted to monochrome, then the colors that were selected are incorrect. This rule is true not exclusively for icons but for the entire graphic design.
Second, you will probably unable to apply safe RGB. Sure, you can select internet colors only, but this limits you greatly. Gradients, shadows, dithering and many other tricks will not be available to you.
Third, try to enlarge the portion of "flat" color. The more consistently colored parts without blurring and jumps your picture has, the more neat it appears. Pictograms are too small and the over usage of complex filters makes the picture look messy.
Fourth, gradients. This is a wonderful instrument which can change the look of any picture. Other than esthetics, gradients are an ideal way to abolish the "broken line" effect (lines with too long basic elements). But be attentive when applying them because too much gradients can kill the plain color, and be unable to fit into the gif palette.
Fifth, shadows and flares. All rules for using shadows and flares in icon making are totally identical to the rules of the overall graphic design. The only ine I have to note: create everything by hand. Don't apply effects, make all shadows and flares in a separate layer and after that edit its transparency. When applying effects, you rarely know what the result will be. It is bad when you don't control the process of creating of a composition. It is awful if you can't control it if creating miniatures.
And, finally, sixth. Nuancing is the main detail of pictogram creation, which greatly affects the esthetic look of the composition. If the green human eye in the picture has the size of 1 pixel, increase the color saturation. For instance, instead of 0, 131, 159 make 71, 195, 242. It is indifferent that the human eye can't have this color; in the first example it will look like a gray dot, and in the second example it will really be a blue eye.
Thoroughly control the picture, do not let the visual tricks to spoil your work. It is acceptable if objects is not consistent technically, but the whole image must be flawless.
As an example, I pictured the pack of juice standing in front of me. The image has plain color, gradients with broken lines, shades and flares and nuances.
If I talked about something bigger than icon creation, this chapter wouldn't fit into an entire book, but the resolution of compositions restricts fonts too.
The size of symbols is the leading issue as opposed to their look. Nearly in any case, unless the letters are the primary part of the composition, the font size must be reduced to the largest extent possible.
In general, almost any graphic company has its own font with small characters. This font can be crafted in a couple of hours. You can browse the internet and make your own library of very interesting fonts. First of all, I would recommend you to download the DS Pixel and Seventen 7Vedi webpage as well as the entire series of fonts from the Lakmus Lab website.
If you don't need a new font, small sizes of Arial and Verdana will do. As a last option, you can create the needed letters by hand.
There are quite a few rules there. First, characters cannot be less than 5 pixels high or less than 3 pixels wide.
Second, letters should not use anti-aliasing. It turns the text into an incomprehensible mixture of pixels.
Though, there are no rules without exceptions and the 5-point Arial looks perfectly readable.