Why Pixel Perfect is Impossible: Download Speeds & File Size
For this, the fourth entry in this series, we will investigate the roles that download speeds and file sizes play in destroying pixel perfection. Whilst we have previously seen that standard print requirements cannot be imposed, and that the browser and the device all combine to prevent “perfection”, they are all influenced by the combination of download speed and file size.
Download Speed
As I am sure you are aware, the speed of your internet connection varies depends on a number of factors: where you are in the country, how you are connected, and where in the world the website you are visiting is. It is generally known that most users will not wait long for a website to load, with some exceptions; as a consequence, websites must be optimised to be as small and as fast as possible.
File Size
One of the simplest ways to achieve this is to make each file as small as possible. With most textual website content this is easily achieved, however with other media like images and video it is more complicated.
For example, consider this image of a puffin:
This image has been saved at maximum quality, and as you can see has a high level of detail, with plenty of definition in the fish, beak and feathers. However, for it's modest dimensions, it is a large file at about 160 kB. To reduce the file size, we must compress it, by reducing the quality level:
By reducing the quality to 75% of maximum, the filesize has dropped to about 50 kB, with very little difference in the level of detail. If we go further though, then the following will happen:
This image is at 25% of maximum quality, and as you can see there is a noticable drop in quality of the background, the sharpness of the fish and in the detail of the feathers. The filesize is now about 14 kB, or roughly 9% of the original.
As you can see from these images, the filesize can drastically affect the quality - and for pixel perfection nothing less than maximum quality would do.
Conclusion
Slower internet connections, like those imposed on those using mobile internet or in rural areas, require that websites are as small as possible. This requires that every file be compressed to reduce the filesize, which in turn affects the quality - preventing pixel perfection. Getting the level right is a balancing act, and depends on the target audience for your site. We have a number of techniques to help with this - get in touch if you need help!