Exact colour match between printer and a calibrated monitor.
The colours that are printed are the same as the colours
in the actual image. If you have a colour calibrated monitor (please see the
monitor calibration section), then your monitor will also display the exact
colours in the image. Your print will now match your monitor as best it can (the
colours will match, apart from the more saturated colours which your monitor can
show, but your printer\paper combination cannot print - please see the following
section on colour gamut for more details on what colours can be viewed or printed).
Prints will also match when using different papers, providing each paper has been
profiled - although there will also be some subtle differences based on the qualities
of the paper (some papers can display deeper blacks and more saturated colours depending
on their attributes. Generally gloss papers can display a broader range of colours
compared to matte papers, and whiter papers will be able to show the more brighter,
saturated colours compared to a creamier paper.
Maximises the colour gamut of your printer and paper. The colour gamut is basically
all the colours that a device can use - so the gamut of a monitor
is all the colours it can display, whereas the gamut for a printer is all the colours
that it can print (although for a printer, the colour gamut is also limited by what paper
is used too).
When you create or capture an image, you usually set a colour profile to your image
- this is different to the printer profile. It defines what colours can be used
within the image i.e. the colour gamut of the image. Typically this is sRGB or Adobe
RGB.
The sRGB colour space
sRGB is the most standard, and is best used when you want to show images on the
web or to send images to a printing lab (unless the lab specifially states that
they will accept Adobe RGB). Web browsers understand what sRGB is, and can display
the image correctly.
The Adobe RGB colour space
Adobe RGB is more advanced - it has a larger colour gamut, and so can display more
colours. The advantage of this means that with more colours you can get more detail,
smoother colour gradients and so forth. The drawback of this is that your image
editor must recognise Adobe RGB (and almost all do now). If you post an Adobe RGB tagged
image to the web, you will notice it will often be displayed darker than usual - this
is because most web browsers cannot process and display all the colours. It just treats
it as a standard sRGB image, and the colour mapping becomes confused. For your own
editing and printing, it makes sense to use Adobe RGB (especially now that many
advanced digital cameras allow you to capture images with an sRGB or Adobe RGB colour
space - they used to only be sRGB).
The Monitor colour gamut
So your image now has a colour gamut - a range of colours it can display defined by the set colour space.
Guess what - your monitor has a colour gamut too! It
can only display certain colours. It's not much of a problem though. Most modern monitors can
display the colours of the sRGB colour space, and some can display all of the colours of the Adobe RGB colour space
for it to be a non-issue. As long as your monitor is properly calibrated, preferably with a monitor calibrator -
so that the colours that it displays are accurate - then you don't need to worry
too much about the gamut of the monitor. Do note though that as monitors age, they
can wear out. Particularly with CRT monitors, the amount of colours that it can
display gets reduced. It might be that the monitor can no longer display the differences
in the darker shades. You've then got a reduced gamut, and for accurate editing
it would be beneficial to replace your monitor.
The Printer colour gamut
The final colour gamut is the gamut of your printer. This can be where the problem
is when you're trying to get an exact colour match. Most colours are fine until
you get into the very saturated colours. The stronger reds, greens and blues are
the colours which cannot always be printed.
As printer technology advances, more and more of these colours can be printed as
more inks are introduced.
Some printers now have red, green and blue inks as well as the more standard cyan,
magenta, yellow and black inks, because they can then print more of the brighter
colours - the extra inks extend the gamut of the printer which means more colours
can be printed.
The dark colours of the printer can also be a problem - you might notice that your
printer with a standard printer profile does not print all the detail in the shadows of
an image compared to what you can see on the monitor. Quite often this detail gets "blocked" up,
and really needs a custom printer profile to open up the shadow detail by accurately mapping what
dark colours the printer is capable of printing.
The colour gamut of your printer is also affected
by the paper that you use. If you use very white paper, then brighter colours can
be printed as the whiteness of the paper shows through the ink. It the paper is
more creamy coloured, then the colours printed will be slightly duller - you certainly
will not be able to get a pure white. The paper finish will also have an effect
- gloss papers tend to have a larger colour gamut than matte papers.
So how does the printer profile help with the colour gamut? Basically a printer profile will
try to maximise the gamut of colours that your printer can print. Your printer and
paper combinations only have a certain gamut, but your standard printer driver will
almost certainly not be using the full gamut - the driver will be on the safe side.
With a custom printer profile, you should find the gamut gets extended. It might not be by a huge
amount, but there will be at the very least a subtle change. There'll probably be
more shadow detail, brighter colours, and a better distinction between shades of
colours.
Neutral black and white photo printing.
Very few printers can print a neutral monochrome print - more often than not there are colour tints to the shades of grey,
and some shades will show one colour of tint, whilst other shades will show a different
colour. This makes it very difficult to correct. However, with a printer profile your black
and white prints should become neutral as the tint is removed individually from
each shade of grey.
Please note though that a few inks do display a condition
called metamerism - this is where colours change under different lighting conditions.
Metamerism is most noticeable if your printer uses pigment inks (such
as with the Epson 2000, 2100 and 2200 printers), rather than the more popular dye inks. Technology is always
changing though, and there are usually new advances on this with every new inkset release so don't let that
put you off pigment ink printers - pigment inks have their own advantages in durability and archive life.
The result of metamerism means that a neutral print might show a green or a magenta tint when viewed under different lighting.
The cause of the metamerism is due to some of the colours that are contained in
the mix of colours that are used to create the shades of grey. This cannot be solved
using a printer profile, but can be fixed by using a different printer driver program called a RIP.
This controls what ink colours are used to make up the grey patterns, and eliminates
the colours that cause metamerism. Unfortunately the RIP software can cost as much
as the printer. The other alternative is using a monochrome set of inks that will only print black and white images. Without coloured ink, there
is no chance of getting metamerism, and you will definitely get the most neutral prints.