File Types and Their Differences
There are basically two different types of graphics files: vector and bitmapped.
The best file types for custom logos would be the native Adobe Illustrator
file (.ai), a true vector encapsulated postscript file (.eps), windows metafile
(wmf) or Freehand (.fh) file.
The easy, non-technical description of which file types
Why Slipp-Nott insists on vector files:
- Vector files can be scaled up without any
loss in edge detail.
- Vector files will always print at the highest resolution
of the printer.
- Vector files can be easily edited, modified or recolored
and matched as closely as possible.
- Vector files use no compression.
- Vector files
are very small when compared to bitmapped files (usually between 30k
Why bitmapped files are difficult to work with:
- Most bitmapped files are used for letterheads
or business cards and therefore do not have enough information to allow
us to scale the graphics to the printable
size of our bases (15" x 18" for the SCS60 or 26" x 26" for
- Bitmapped or raster files print only as
sharp as their resolution. So even if you have a very expensive, high
a low resolution image
will print just as poorly as it would on a cheap
dot matrix printer.
- If your files happen to be big enough for us to
scale up and print at the appropriate size, they need to be multi-megabyte
files (2+ MB)
- Most bitmapped images use lossy compression schemes
to reduce file size.
- The nature of bitmapped images dictates that
even apparently solid colors are made up of a combination of different
It is almost impossible to change any color without affecting the neighboring
colors or to adjust the colors to match a specific color. Therefore, inevitably,
customers send a file in that is a bitmapped image that was adjusted to print
out properly on one particular printer but because of the nature of color printing,
when it prints on another printer, it must be too dark, too red, too light,
too yellow, too bluish and too something. Color matching an image such as this
is almost impossible without a color profile. Color profiles are used by color
management systems. Explaining what a color management system is and does is
beyond the scope of "easy, non-technical description".
more technical description of what goes on with the different file formats:
Vector files are the ideal file format for logos because they are resolution
independent. In other words, vector files can be scaled to any size without
any image degradation or loss of quality or detail. When you edit a vector
file you edit a shape or geometrical characteristics based on mathematical
formulae. Scaling a vector image up or down in essence changes the variables
in a formula. The same vector file can be used for a business card and can
also be scaled up to print a billboard on the side of a building!
Bitmapped files are Photoshop (.psd), Pict (short for picture), Graphic Interchange
Format (.gif), tagged image file format (.tif), Joint Photographic Experts
Group (.jpg), bitmap (.bmp) and Portable Network Graphics (.png). Photoshop,
Fireworks, Paintshop and other paint programs generate bitmap images, also
called raster images. These images are made up of a grid of small squares
called pixels. Each pixel has a specific color value and location in the
you edit a bitmapped file, you edit individual pixels rather than shapes.
Scaling a bitmapped graphic only changes the size of each pixel. Depending
on the resolution
of the output device and on the resolution of the bitmapped graphic determines
how many "dots" are used to print out each pixel and ultimately
how good a bitmapped image will look when printed.
For example, if the resolution of your graphic is 300 dpi (dots per inch),
your printer is also a 300 dpi printer AND the image will be printed at its
original size (no scaling) then each dot on the printer will correspond to
each dot on the graphic. If you now double the size of the graphic, the final
output size of the graphic will be twice the size in each direction (horizontal
and vertical) but the resolution of the graphic stays the same. In other
words, it is still a 300 dpi graphic, so in order to print it at twice the
dot has to be doubled in size in both the horizontal and vertical direction
so now it will take 4 of your printer's dots for each dot of your graphic.
So as you go up in size on a fixed resolution file, the "blockier" and
jagged the edges look and the more detail you appear to lose. In general,
you can double, triple or sometimes quadruple the size of a bitmapped graphic
image degradation is noticeable. This is not a hard and fast rule, among
other factors, things such as the nature of the image, the quality of the
and the software you use to scale it up will determine the output quality
of the image.
Lossy vs. Lossless compression:
While a simple concept and almost self-explanatory the
issue of compression is quite sophisticated. Lossless compression reduces
the file size of an image
when it is closed but when opened for viewing or printing, it is displayed
or printed at full quality. Lossy compression actually discards some information
everytime the file is saved even if the file has not been changed. Using
lossy compression means that your file begins to degrade from the first time
saved. The level of compression (high or low) determines how much or how
little is discarded and that is reason that a preview is presented prior
a file. Keep in mind that once that information has been discarded it can
never be recovered. Depending on which compression technique and the level
used determines the quality of final image. VECTOR FILES USE NO COMPRESSION.
Specifying Colors and Color Management Systems:
A color management is needed to "manage" colors of an image in order
to reproduce the image as it was originally meant to be displayed or printed.
Most of us see in color but our eyes like transistors, inks, monitors, electron
guns, LCD panels, toners and papers while very similar are all different. Since
one cannot control or predict how someone else will actually "see" a
particular color, several companies have come up with a collection of colors
and given them names along with specific combinations of colors/inks so as
to create these colors. In order to enable these colors to be "matched" they
create something known as color swatches and bind them into little books.
These swatch books are then distributed/sold to the graphics industry so
can refer to a specific color by name and be able to see them even though
they are not in the same location. This method of specifying a color allows
accurate method referencing of colors by phone, fax or through computer communications.
Color swatch books work well for people describing colors to each other but
not for computers, cameras, scanners and printers. Those devices need something
that allows all of them to know how each of these colors is going to be rendered.
This something, is known as a color management system (CMS). A CMS uses things
called ICC color profiles. ICC color profiles are based on specifications
established by the International
Color Consortium (ICC) and are generated
by a color calibration
system. The color calibration system generates a chart of known colors and
these colors are output or read in the case of a scannerr or digital camera
that needs to be "profiled". These colors should be read back (if
calibrating a printer) into the computer and analyzed by the color profile
generating software so that it can generate a profile that indicates to the
CMS the color spectrum should be handled by the various devices (digital
camera, computer, printer, display or scanner) to properly represent the
The bottom line:
While both vector files and bitmapped files require some form of color management,
vector files are far easier to work with and generate a superior representation
of your logo.