- Category: Digital Artist
- Last Updated on Thursday, 11 October 2012 18:12
- Published on Thursday, 11 October 2012 18:09
- Written by LEW
- Hits: 862
Have you ever tried setting one of your own photos or graphics as computer wallpaper and been somewhat disappointed with the results? It turns out there is a little bit more to computer wallpaper, beyond just selecting a picture or graphic. So let us take a minute to review a few things about how a computer displays a background image and what we should be considering when we select one. Things to consider include resolution, aspect, and composition.
Wallpaper is also no longer in the province of computers. Strictly speaking, of course, devices like tablets, cell phones, music players and Personal Digital Assistants (remember the days of PDA’s) all have computers in them. They also expand the display types that wallpaper must be able to conform to and work on.
Used on Debian Squeeze KDE Desktop
When planning to use an image for computer wallpaper, the first factor to consider is size or resolution. For example if your image is 640 pixels wide and 400 pixels high (commonly expressed as 640x400), it will not look very good on a 1280x1024 pixel screen size. However, a 1600x1200 pixel image will look very good. Do not worry about where the numbers come from, as we will cover that when we talk about common aspect ratios. The important thing to take away is that bigger graphics tend to look better when shrunk to lower resolutions, while smaller graphics tend to look worse when expanded to higher resolutions.
So always start with the biggest base graphic possible. Save this as your starting point and do not overwrite it. In fact, make a copy and work only with the copy. If you’re original image is a JPG, save your copy in a lossless format. Most paint programs have their own formats which are much better for editing and saving graphics in. If your paint program does not have its own format, consider using the public domain PNG format. Regardless, it is pretty much guaranteed that you will want/have to do some manipulation with a graphic or paint program to enhance your graphic and compose the final image.
Color depth could also be considered as part of resolution. However today it is not the issue it once was. In the good old days many computers would only display a color depth of 8 bits or less (8 bits is 256 colors). Today most graphic devices have at least 18 bit color depth (262,144 colors), with many having 24 bit color depth (16,777,216 colors), referred to as true color, which seems to be the current standard. 32 bit or more, referred to as deep color, is supported by some graphics cards. In the end if you have at least an 18 bit color depth, you will not have to worry about things like dithering and other tricks used in the good old days to simulate more colors.
Next we visit aspect ratio. This is the ratio between the width and height of the screen. In the resolution examples, if you divide the width into the height you will get 1.333 for each one. This is equivalent to what is known as a “4:3” aspect ratio. Older computers screens, regardless of size, used this aspect ratio almost exclusively. Which would make things pretty simple if that was the case today? Wide screen is rapidly becoming the new favorite aspect ratio. Today there are a variety of aspect ratios you may run across in both computers and portable electronics devices like phones.
Most aspect rations can be turned around, for instance using a tablet with a resolution ratio of 1200x800 in landscape mode would have a resolution ratio of 800x1200 in portrait mode. Bearing that in mind some of the common aspect ratios and screen sizes today are;
4:3 1600x1200 1280x960 1024x768
16:9 2560x1440 1600x900 1280x720
16:10 2560x1600 1440x900 1280x800
Depending on monitor and video hardware there are obviously other aspect ratio and screen size combinations. When we consider smart phones and other portable devices we can add additional ratio’s like; 15:9 or 3:2.
Aspect ratio can also affect how images are scaled when the graphic aspect ratio is different than the screen aspect ratio. When used as wallpaper there are four ways that graphics are handled; centered, tiled, stretched, and zoomed.
If a graphic matches both Resolution and aspect, it is usually centered. That is to say it sits in the center of the screen and fits perfectly. When resolution and aspect do not match, the other three methods come in to play.
If the aspect ratio is the same, an image can be zoomed in or out to fill the screen. If the aspect ratios do not match, then zooming the image will crop (hide) some of the graphic or leave blank areas on the screen. The image can also be stretched to fit, changing its aspect ratio and distorting the image. If the image is small enough or designed for it, it can be tiled repeatedly to fill the screen background.
Keeping both resolution and aspect in mind, we consider composition. Composition in this case refers to the visual interaction between the wallpaper and desktop icons and widgets. We want to see our wallpaper, but we also need to see other items on the desktop. So it is worthwhile to consider where desktop items are commonly located when composing wallpaper.
Additionally, we may want to compose multiple images for each aspect ratio we are likely to use. As long as we keep the resolution in line with the maximum resolution, the images can be zoomed to fit with good results. To get the absolute best results, we would want to make images not only for each aspect but for each resolution.
In this example I am using an image with a vastly different aspect ratio than any computer uses to make some of the possible issues much easier to see.
I found this image on Flicker. It is called Mara, and was taken by EF Photography.
The first two tests show an image that has been zoomed to fit an aspect ratio box. In the one case we will see large parts of the image will be cropped, and in the other we see large blank areas. The third image is distorted by being streched.
Since the image is over 3000 pixels wide and 5000 pixels high, I can do some composition and use just part of the image. In my paint program I add a transparent layer and superimpose an aspect ratio box which I can scale and move around to get the part of the image I want to use. I then crop the image and delete the transparent layer to get rid of the box. Finally I scale the image to the correct size. You may also chose additional adjustments, like contrast, brightness, white balance, dynamic range adjustment, etc, etc, … How you do all this will depend on the paint program you are using.
Build an Aspect Ratio Box
What I do is open a new graphic in my paint program that is the correct size. I then turn on the alpha channel and delete any fill. I put a red border around the entire picture. I save this as a PNG to preserve the transparency.
I can then easily import this as a new transparent layer over a picture I want to crop.
Making computer wallpaper is fun and easy. That sounds so cliché. Anyway, give it a try. If you don’t have any good pictures, there are several sites that offer free stock photos, like the one I used in the example.