HOW TO IMPROVE THE
DEFINITION OF A TV PICTURE: Watch in TrueColour
TV factory settings are to make it look good in the
showrooms. That's why it's in your living room. But over
time, the settings may change through ageing components,
the kids capture the remote or you have your own personal
Most people are unaware of the potential of the
definition that is available. So let's start at the
beginning. A picture (video) signal is sent to your home
that includes black-and-white and colour information. No
picture information can be sent brighter than white or
darker than black. If you turn up the brightness, black
shadows becomes only dark grey shadows. you cannot see
blacker than black! Some TV soaps seem to be made in the
dark and they keep the curtains or blinds closed in the
background. It's not your TV!
may not be aware that the colour information is about
half the definition (or detail) of the black-and-white
signal. Therefore, in certain circumstances, where there
is high colour, your overall definition is
TV set also has physical and electrical limits. If you
turn the brightness or colour controls full up, there is
a trade-off between GAIN and DEFINITION due to the way
electronic amplification works, especially for older CRT
televisions. More gain could mean less definition.
this test: Go to a text page such as Teletext and adjust
the contrast and brightness controls and watch what
happens to a single letter, preferably a full stop - it
will probably 'bloom' or grow in size as you turn it
can you do? Plenty actually. There are two strategies to
optimise a TV picture:
- What you can do and Technical:
What an workshop engineer can achieve.
Let's start with the User tips:
1. Reduce the colour control to zero so you are
displaying a black-and-white picture.
Adjust the brightness and contrast controls to
3. Find a channel which is devoted to Text. This could be
CeeFax, Sky text S4C/2 (where available) etc.
3. Adjust brightness and contrast
controls so that:
A. In the black areas, the lines of the picture are just
visible . Remember you won't see anything blacker than
black. (You can check also this later when watching a
channel showing a widescreen film where there are black
bars top and bottom of the screen.)
B. The White of the picture turns from light gey to JUST
white. Hopefully, this is well before the point at which
the picture begins to 'bloom' or spread.
You may find you have to use a combination of both
contrast and brightness controls to find the optimum
4. On-screen graphics are usually sent at 100% colour
saturation which means you can adjust for the optimum
amount needed. Adjust the colour control
until a colour graphic is just 'loaded' with colour, then
just back it off very slightly. If the colour looks
flourescent, that's WAY too much colour. If necessary,
compare the level of colour with an independent source -
e.g. a web page. This allows you to discern the 'true'
This 'true' colour can be checked with outdoor camera
shots. Good neutral sources are the BBC's Antiques
Roadshow or Channel Four's 'Time Team' where the lighting
is natural sunlight and skin tones should look natural;
NOT Kilroy orange or flat biege. Skin tones are quite
subtle. Try looking at skin tone from the perspective of
an artist. Remember that makeup is used on presenters and
actors, including the men. Grass is not primary colour
green but is much lighter because there is usually other
plants mixed in with it. Studio shots are poor light
sources, for the studio lighting has a narrower spectrum,
giving people a cartoon look.
5. Congratulations, You're done!
NOTE: The colour control is now probably
set at a significantly lower level than that at what you
are used to. Please be prepared for resistance when your
family/significant others view the TV. After you have
optimised it; You are likely to get remarks such as:
"It doesn't look right"
"It looks horrible"
and "You've done something
to that TV".
They will judge the picture from what they are USED to
watching. "TV pictures 'should' be
The picture you now have (and to which they will become
accustomed) is more true to life. You are likely to see
much more detail, different shades and styles which
directors of films and programmes wanted to use to
represent the mood of the film. Much of which you may
have missed before. Advertisements in particular, are
for the Technical tips.
tips are for the use of a qualified engineer only! TV
sets, particularly older sets with cathode ray tubes
(CRT) contain circuits that generate KILOVOLTS, with the
emphasis on the KIL! You can also destroy digital
circuits with static electricity generated from clothing,
carpets and movement etc. If you are
unqualified, please leave well alone. A TV costs £100 -
£10000. You on the other hand are priceless.
1. FOR CRT sets, Readjust the focus
control (yes! there is one!) so the CRT beam output is at
the sharpest setting - e.g. the smallest spot size. Most
circuits are out of alignment through age or poor
previous setting up. The sharpest setting is recommended
because the set is normally viewed from five screen
widths - approximately 4 metres away for standard
definition TV's - (10-12 feet in old money).
2. Using the (usually) hidden on-screen menu,
Adjust the picture height and width critically to the
edge of the screen. (for the correct ratio). Most TV CRT
sets overscan by 10% and Flat screen TV's can
under-sample the available data. As the lines increase in
density, it means the resolution will correspondingly
appear to increase by a similar amount
3. Adjust the colour foreground/background controls so
that dark grey IS dark grey, without any (colour) tint
and that bright white is the 'correct' white, again,
without any hint of colour. In the factory, the picture
is set to look slightly blue in order to sell the set.
The engineer can set it so it is pure white (Luminance
'C' or 'D').
For Flat Screen TV's, select the picture of 1:1
pixel matching where possible. Some rescaling
introduces picture artifacts which can significantly can
impair the picture.
For all sets, reduce distorion to the minimum by selecting
the correct format. So for an older programme,
if it is shown in the older squarer format of 4:3, resist
the temptation to 'stretch' it to fill the screen.
Furthermore, resist the temptation to stretch a stretched
picture. That is NOT a good look!
Congratulations! you've now got a picture that shows the
original source as it was intended by the programme's
director. You could find that visitors to your home may
even comment on the quality of the picture!