The
EBU colour bars is a television
test card
A test card, also known as a test pattern or start-up/closedown test, is a television test signal, typically broadcast at times when the transmitter is active but no program is being broadcast (often at sign-on and sign-off).
Used since the ea ...
used to check if a video
signal
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...
has been altered by recording or transmission, and what adjustments must be made to bring it back to specification. It is also used for setting a television monitor or receiver to reproduce
chrominance
Chrominance (''chroma'' or ''C'' for short) is the signal used in video systems to convey the color information of the picture (see YUV color model), separately from the accompanying luma signal (or Y' for short). Chrominance is usually represente ...
and
luminance information correctly. The EBU bars are most commonly shown arranged side-by-side in a vertical manner (as in the images in this article), though some broadcasters – such as
TVP in Poland, and
Gabon Télévision in Gabon – were known to have aired a horizontal version of the EBU bars.
It is similar to the
SMPTE color bars, although that pattern is typically associated with the
NTSC
The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...
analogue colour TV system. Many test cards, such as
Philips PM5544
The Philips PM5544 is a television pattern generator, most commonly used to provide a television station with a complex test card commonly referred to as a Philips Pattern or PTV Circle pattern. The content and layout of the pattern was designed ...
or
Telefunken FuBK, feature elements equivalent to the EBU colour bars.
75% Colour Bars
The 75% Colour Bars or EBU/
IBA 100/0/75/0 Colour Bars pattern
is very similar to the SMPTE colour bars pattern, although it only features seven colour bars, and the white bar is at 100% intensity.
There is a variant where the white bar is also at 75% intensity (EBU 75/0/75/0). This pattern is generated by certain types of test equipment – including the Philips PM5519.
The signal values of these bars for the
PAL
Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...
analogue system are:
''Displayed colours are converted from the original PAL BT.601 colour space to sRGB – the colour space used on web pages. They are only approximate, giving a notion of how the bars would look on a calibrated PAL display.''
100% Colour Bars
An alternate form of colour bars is the 100% Colour Bars or EBU 100/0/100/0 Colour Bars pattern (specified in ITU-R Rec. BT.1729
), also known as the
RGB
The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three addi ...
pattern or full field bars, which consists of eight vertical bars of 100% intensity, and does not include the castellation or luminance patterns. Like the SMPTE colour bars pattern, the colour order is white, yellow, cyan, green, magenta, red, and blue – but with an additional column of saturated black. This pattern is used to check peak colour levels, and colour saturation, as well as colour alignment. The 100% pattern is not as common as the SMPTE bars, or the above-mentioned EBU 75% pattern, but many pieces of test equipment can be selected to generate either one. Many professional cameras can be set to generate a 100% pattern for calibration of broadcast or recording equipment, especially in a multi-camera installation where all camera signals must match.
Standard Definition
EBU colour bar values for
standard-definition television systems following
BT.601, as specified in ITU-R Rec. BT.1729:
''Displayed colours are converted from the original PAL BT.601 colour space to sRGB – the colour space used on web pages. They are only approximate, but represent what is seen on a properly calibrated display using the original colour space.''
Calculation of
(
luminance) and
(
colour difference
In color science, color difference or color distance is the separation between two colors. This metric allows quantified examination of a notion that formerly could only be described with adjectives. Quantification of these properties is of great ...
) signals from
,
and
components according to BT.601 is as follows:
:
High Definition
EBU colour bar values for
high definition TV systems following
BT.709, as specified in ITU-R Rec. BT.1729:
Calculation of
(luminance) and
(colour difference) signals from
,
and
components according to BT.709 is as follows:
:
HDR UHDTV
In 2020 the EBU published a newer colour bar pattern named Colour Bars for Use in the Production of Hybrid Log Gamma (HDR) UHDTV, designed for
HDR broadcasts, taking into account the extended
colour gamut of these systems.
It includes 100% and 75% ITU-R
BT.2100 HLG colour bars, and colour bars which can be converted to ITU-R
BT.709 75% bars when ''scene-light'' and ''display-light'' mathematical transforms defined in ITU-R BT.2408 are used.
This pattern allows testing of
UHDTV
Ultra-high-definition television (also known as Ultra HD television, Ultra HD, UHDTV, UHD and Super Hi-Vision) today includes 4K UHD and 8K UHD, which are two digital video formats with an aspect ratio of 16:9. These were first proposed by ...
to
HDTV
High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
conversion, measuring luminance response, saturation and hue shifts, and checking near‑black performance. It can also be used to check for correct hardware settings, transmission chain errors, and proper
colour space
A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital represent ...
transforms from ITU‑R BT.2100 HLG to ITU‑R BT.709.
Versions of the pattern are freely available as a still image or video file.
The pattern is similar to the
ITU-R
The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications.
Its role is to manage the international radio-frequency sp ...
recommendation BT.2111 that also covers the
PQ transfer function.
Another similar pattern called Colour Bar Test Pattern for Hybrid Log-Gamma (HLG) High Dynamic Range Television (HDR-TV) System was developed by
ARIB
The , commonly known as , is a standardization organization in Japan. ARIB is designated as the center of promotion of the efficient use of the radio spectrum and designated frequency change support agency. Its activities include those previously ...
in 2018 (ARIB STD-B72), based on the
SMPTE color bars commonly used in Japan and United States.
See also
*
SMPTE color bars
*
Indian-head test pattern
The Indian-head test pattern is a test card created by RCA of Harrison, New Jersey, which became the standard image of the RCA TK-1 monoscope. It features a drawing of a Native American wearing a headdress and numerous graphic elements designe ...
*
Test Card F
*
Philips PM5544
The Philips PM5544 is a television pattern generator, most commonly used to provide a television station with a complex test card commonly referred to as a Philips Pattern or PTV Circle pattern. The content and layout of the pattern was designed ...
*
Telefunken FuBK
References
External link
Colour Bars and PLUGE
{{European Broadcasting Union
Test cards
Television terminology
European Broadcasting Union