Non-photo blue
Encyclopedia
Non-photo blue is a common tool used in the graphic design
and print
industry
. It is a particular shade of blue
that can not be detected by graphic arts cameras. This allows layout editors to write notes to the printer on the print flat (the image that is to be photographed and sent to print) which will not show in the final form. As well as this, it allows artists to lay down sketch
lines without the need to erase after inking
.
As of late, with digital scanning and image manipulation, non-photo blue fulfils its function in a different way. The artist can do his or her sketch and inking in the traditional method and scan the page. Most scanners will detect the light blue lines. However, shifting to greyscale
and increasing the contrast
and brightness
will cause the blue to disappear. Another common approach involves replacing the blue channel
with another channel – typically the red channel. The exact processes may differ depending on the scanner, settings and image-editing software, but the concept remains the same.
The difference between the non-photo blue and black ink is vast enough that digital image manipulation can separate the two easily. If a black-and-white bitmap setting is scanned in, the exposure or threshold number can be set high enough to detect the black ink or dark images being scanned, but low enough to leave out the non-photo blue. On a threshold scale of 0–255, this number would be approximately 140. Only with a considerably high threshold setting will the blue be detected. However, a setting this high may greatly distort the black lines and add a lot of noise
and black speckles to the image, making it almost indistinguishable. Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head.
There is no exact colour within the Pantone Matching System
that matches non-photo blue.
Graphic design
Graphic design is a creative process – most often involving a client and a designer and usually completed in conjunction with producers of form – undertaken in order to convey a specific message to a targeted audience...
and print
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry
Industry
Industry refers to the production of an economic good or service within an economy.-Industrial sectors:There are four key industrial economic sectors: the primary sector, largely raw material extraction industries such as mining and farming; the secondary sector, involving refining, construction,...
. It is a particular shade of blue
Blue
Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
that can not be detected by graphic arts cameras. This allows layout editors to write notes to the printer on the print flat (the image that is to be photographed and sent to print) which will not show in the final form. As well as this, it allows artists to lay down sketch
Sketch (drawing)
A sketch is a rapidly executed freehand drawing that is not usually intended as a finished work...
lines without the need to erase after inking
Inking
Inking is the process of using a liquid known as ink, which contains natural or man-made pigment.* Inking is work done by a Inker, one kind of commercial artistIn biology:...
.
As of late, with digital scanning and image manipulation, non-photo blue fulfils its function in a different way. The artist can do his or her sketch and inking in the traditional method and scan the page. Most scanners will detect the light blue lines. However, shifting to greyscale
Grayscale
In photography and computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information...
and increasing the contrast
Contrast (vision)
Contrast is the difference in visual properties that makes an object distinguishable from other objects and the background. In visual perception of the real world, contrast is determined by the difference in the color and brightness of the object and other objects within the same field of view...
and brightness
Brightness
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target...
will cause the blue to disappear. Another common approach involves replacing the blue channel
Channel (digital image)
Color digital images are made of pixels, and pixels are made of combinations of primary colors. A channel in this context is the grayscale image of the same size as a color image, made of just one of these primary colors. For instance, an image from a standard digital camera will have a red, green...
with another channel – typically the red channel. The exact processes may differ depending on the scanner, settings and image-editing software, but the concept remains the same.
The difference between the non-photo blue and black ink is vast enough that digital image manipulation can separate the two easily. If a black-and-white bitmap setting is scanned in, the exposure or threshold number can be set high enough to detect the black ink or dark images being scanned, but low enough to leave out the non-photo blue. On a threshold scale of 0–255, this number would be approximately 140. Only with a considerably high threshold setting will the blue be detected. However, a setting this high may greatly distort the black lines and add a lot of noise
Noise
In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise heard when listening to a weak radio transmission with significant electrical noise...
and black speckles to the image, making it almost indistinguishable. Scanning in black-and-white makes it possible for the non-photo blue still to serve its original purpose, as notes and rough sketching lines can be placed throughout the image being scanned and remain undetected by the scan head.
There is no exact colour within the Pantone Matching System
Pantone
Pantone Inc. is a corporation headquartered in Carlstadt, New Jersey, USA. The company is best known for its Pantone Matching System , a proprietary color space...
that matches non-photo blue.
Non-photo blue in popular culture
MusicMusic
Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...
- "Non-Photo Blue" is the name of the first track from the band PinbackPinbackPinback is an indie rock band from San Diego, California, currently signed to Temporary Residence Ltd. The band was formed in 1998 by singers, songwriters and multi-instrumentalists Armistead Burwell Smith IV and Rob Crow. Tom Zinser, Chris Prescott, and Mario Rubalcaba have all contributed drums...
's album Summer in AbaddonSummer in AbaddonSummer in Abaddon is the third album released by indie rock band Pinback.-Track listing:# "Non-Photo Blue" – 3:43# "Sender" – 4:58# "Syracuse" – 3:49# "Bloods on Fire" – 4:12# "Fortress" – 4:10# "This Red Book" – 3:56# "Soaked" – 4:24...
, released in 2004.