Stuff You Look

12 October 2013

Video and color technology

Video formats

Resolution :
Frame is composed of picture elements. Conventional TV screens are made up of horizontal set of picture elements commonly called as lines. The picture elements were sent as "sine" signals. The number of lines and the number of the above signals put together were called as "Resolution".

Video is basically a sequence of images displayed or flashed in a pattern (rapidly) just like we do in animation. The number of frames per second (fps) called as "frame rate"; were used to measure the quality of video or picture motion. Higher frame rates results in smoother motions.

NTSC (National Television Standards Committee) is the video standard used in America and Japan and Phase Alternating Lines (PAL) is used in Europe, Australia, Middle East) is
NTSC video usually runs at 30 fps (with 525 lines, 6MHz spacing), whereas PAL runs at 25 fps (with 625 lines, 5 MHz spacing).
NTSC video images usually runs in 720 X 486 pixel ratio while PAL video images frames are always 720 X 576 pixels.

Pixels is a way of measuring resolution. The number of pixels in an image is sometimes called "Resolution". Each pixel is a sample of an original image, and a combination of these will make up the actual image.

Pixels per inch (ppi) is used as a measure for specifying the image quality; especially in digital monitors or photography. Most books and magazines require 300 ppi for photo quality. Dots per inch (dpi) is more or less similar but differs in that they were used in printers as a measure of the number of dots to be printed.

The basic resolution and pixel description were shown below

Resolution - Megapixels (MP)

(640 X 480) - 0.3MP; VGA video
(1024 X 768) - 0.8MP; XGA video; 4:3 aspect ratio
(1280 X 960) - 1MP,
(1366 X 768) - 1MP, common laptop display
(1600 x 1200) - 2MP; UXGA video
(2048 X 1536) - 3MP; QXGA

Common aspect ratios for display

4:3 - Old computer monitor standard
5:4 - (1280 X 1024 displays)
16:10 - (1280 X 800; 1680 X 1050 dispalys)
16:9 - widescreen (1920 X 1080; HD video standard; best for computer displays)
Emerging aspect ratio displays : 256:135 - (4096 X 2160; famously called as 4K standard)

16:9 aspect ratio is considered the best display for applications like games, movies, computers, TV/DVD and more. 720p with 1280 X 720 (0.9 MP) and 16:9 widescreen aspect ratio is the most common used video/movie format.

Standard-definition television (SDTV)

576i (720 X 576); i refers to splitting into two fields- here 288 lines
Enhanced-definition television (EDTV)
480p (720 X 480)
576p (720 X 576)

p refers to progressive scan

High-definition TV (HDTV)

720P (1280 X 720)
1080i (1920 X 1080) - split into 540 lines
1080p (1920 X 1080)
Ultra-high-definition tv (UHDTV)
2160p (3840 X 2160)
4320p (7680 X 4320)
8640p (15360 X 8640)
Full hd measures 1080p; 1920X1080 pixel (2.1MP) with widescreen aspect ratio of 16:9
Blue-ray discs are able to hold HD content.

Some online resources :

More about resolution sizes - here
check detailed picture formats - here
More about display standards - here

Color Technology

All the display screens uses three basic colors, popularly called as additive primary colors. They are Red, Green and blue (RGB). Add RGB in different proportions to get a broad array of colors and a perfect combination of these three pure colors adds up to white color.

RGB input devices - TV, Video cameras, image scanners and digital cameras
RGB output devices - CRT, LCD, LED, OLED displays, plasma, computer and mobile phone displays, video projectors.

On the other hand CMYK is used in color printing technology and is referred as "substractive colors". CMYK stands for cyan, magneta, yellow and black (Key); because when CMY was mixed, we get black ( but not true; thats why it's called key). CMY were usually called "primaries" while RGB, were called as "secondaries" because by the use CMY combinations, we will get RGB colors.

CMYK pic. - http://en.wikipedia.org/wiki/CMYK_color_model

RGB pic. - http://en.wikipedia.org/wiki/RGB

difference between RGB and CMYK from wiki

If RGB values are zero (0,0,0)- (least), result will be black

RGB Value 255 (255,255,255) - (maximum), result will be brightest white.

RGB - (255,0,0) - Red

RGB - (0,0,255) -Blue

RGB - (255,255,0) - Yellow

Remember that RGB (used in photography, electronic monitors or displays using "lights") usually uses white color as additive combination to deliver color visual in black background (black monitors) where as in CMYK, white is the background (printing paper) and black results from combination of these color "inks".

Other online resources

More RGB color codings - here
List of colors - here
numerical values for different colors of RGB - here
Something about complementary colors - here

Download Pdf format of this page - here

References :

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Illustrations techniques

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Illustrations

Usually visualization or depictions like sketching, painting, drawing and even photography by an artist is called Illustration.

Illustration techniques

Engraving

It is the art of making designs on to a hard and flat surfaces, by cutting grooves into it.

Tool used - Burins or graves
Surfaces - Silver, nickel, gold, steel, brass, titanium, copper, wood, stone and more
Uses - making of logos for industries like printing, coins and utensils

Gravers pic shown below

Gun Bow - hand engraving machine picture shown below

Etching
It is the process of making designs by cutting on metal surfaces using strong acid or mordant.

Surfaces - copper, zinc and steel
Uses - manufacturing of printed circuit boards and semi conductor devise, glass

Woodcut (Xylography)
It is the technique of printmaking, where a image is carved into the surface of a block of wood.
Wood cut picture shown below.

Linocut
Similar to Wood cut, but the material Linoleum (floor covering made from linseed oil) is used.
Lino-cutting using handheld gouger tool shown below.

Other techniques

Sumi-E (Also referred as Ink wash painting)
Pen and Ink illustration

Some related terms :

Ideogram :

Ideograph or Ideogram is a graphic symbol that represents an idea or concept.

Pictogram or pictograph is an other term (an ideogram) that conveys its meaning through its pictorial resemblance to a physical object.

Petroglyph :

Also called "Rock engravings" are pictograph and logo-gram images created by removing part of a rock surfaces by incising, picking, carving and abrading. An example shown below.

Petroforms :

Known as boulder outlines mostly human-made shapes and patterns made by lining up large rocks on the open ground.

Stick figure :

It is a very simple drawing of a person or animal, composed of a few lines, curves and dots.

Intaglio

It is the group of printing and printmaking techniques in which a image is cut (with a V shape) into a surface and the cut portion holds the ink.

techniques - Engraving, etching, dry point etc.

Writing systems :

Devanagari :

The most commonly used script for Sanskrit and is used to write Hindi, Marathi, Nepal, Awadhi, Bhojpuri, Bodo, Gujari, Pahari, Konkani, Magahi, Maithili, Marwari, Bhili, Newar, Santhali, Tharu, Sindhi, Dogri, Sherpa, Kashmiri and Punjabi.

Tamil language was the first Indian language to be declared as "classical language" by the government of India in 2004. Tamil is one of the longest surviving classical languages in the world !!! and is considered as "the only continuous recognizable language and also one of the richest literature's in the world".

Hieroglyph - here
More about writing systems - here

Download Pdf format of this page - here

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References :

All the images shown above were sourced from wikipedia
http://en.wikipedia.org/wiki/Illustration
http://en.wikipedia.org/wiki/Pictogram