Computers consume our daily lives and as they evolve we need
to learn more to keep up. But as this occurs many of us forget or never learn
the basics. A basic that everyone in a design and marketing position needs to
know is image formats. This is the process of organizing and storing digital images.
When images are saved, you are compressing the number of
pixels and color depth. There is a whole algorithm involved when saving that
explains the file size based on the number of pixels and colors, which is quite
interesting. However, I will stick with a surface explanation in hopes of not
losing your attention half way through this post.
In terms of algorithms it is important to remember that computers
display color in RGB (red, green and blue). These colors are displayed using
light, which explains why the color on computer monitors are much more vibrant
than printed materials. Printed materials use CMYK (cyan, magenta, yellow and
black). These colors are mixed together to create a wide spectrum of colors,
but will never have as many colors as RGB. So the takeaway from this is that every
format is unique to how it saves the number of colors.
While there are many image formats out there, we will only
focus on the best ones for digital and print: TIFF, JPEG, PNG and GIF.
JPEG
- Best used for the web
- Displays up to 16 million colors
- Most widely used and accepted
- Discards a significant amount of data
- Does not support transparency
- Cannot be animated
- Suffers from generational degradation – image quality suffers when repeatedly edited and saved
GIF
- Best used for web animation
- Used for images with limited colors
- Displays only 256 colors
- Creates small file sizes
- Supports transparency
TIFF
- Best used for print
- High quality image – all information is stored
- Keeps layers
- Very large file size
PNG
- Retains quality and detail
- Displays only 256 colors
- Creates smaller file sizes than GIF
- Supports transparency
- Cannot be animated
- Not supported by all web browsers
- Not good for large images because it will create very large files
From this information we see that the formats best used for
web are JPEG, GIF and PNG and the best format for print is TIFF. Retaining high
quality images is very important in print, whereas web applications are more
concerned about file size in order to have web pages load faster.
I’ve learned that it is best practice to always save your
original images at the highest quality possible. Remember that you can always
size images down, but you can never save images up. While there are programs
out there that help with image enlargements they will never produce the same
results as having an original high quality image. Understanding and applying
this will provide much more flexibility in the long run when deciding how to
apply images to your design or marketing strategies.
