832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 19

COLOR MANAGEMENT FOR PRINTING

What is color

A Colour is the sensation produced in response to selective absorption of wavelengths

from visible light It possesses the attributes of Brightness Colourfulness and Hue Aninternational standard developed by CIE can be used for measurement of these attributes

for any colour

An alternative way of specifying colour is to refer to a colour order system such as the

Munsell or NCS systems ( widely used in Europe)

As you might suspect there are different types of color Now is when you can throw the

color wheel out the window

RGB Color This is color based upon light Your computer monitor and television use

RGB The name RGB stands for Red Green Blue which are the 3 primaries (withgreen replacing yellow) By combining these 3 colors any other color can be produced

Remember this color method is only used with light sources it does not apply to

printing

CMYK Color This is the color method based upon pigments CMYK stands for Cyan

Magenta Yellow and Black (its what the K stands for) Using these 4 colors most other

colors can be achieved Unfortunately CMYK cannot reproduce the same amount of colors as RGB can which is why yellow-greens sometimes look a bit muddy when

printed This problem could be overcome by using a conversion formula This is the

method used by printers the world over and is also a clever way of mixing paints

Pantone (PMS) Color This is yet another printing color method PMS stands for

Pantone Matching System and is a large list of specially mixed colors made by the

Pantone Corporation Instead of using CMYK to create colors the pigments are createdindividually for purity For example if I wanted to use a Red-Violet color Id pick PMS

233M The color would be made exclusively for my project and would always print

exactly how I want The only drawback to using PMS colors is that theyre only useful for projects with few colors Theyre also expensive

Color printing is the reproduction of an image or text in color While there are manytechniques for reproducing images in color specific graphic processes and industrial

equipment are used for mass reproduction of color images on paper In this sense color

printing involves reproduction techniques suited for printing presses capable of thousands or millions of impressions for publishing newspapers and magazines

brochures cards posters and similar mass-market items In this type of industrial or

commercial printing the technique used to print full-color images such as color

photographs is referred to as four-color-process or merely process color system Thishas increased now to around 78 and even to 12 color digital printing

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 29

Process Color Systems

Looking at the different process color printing systems will help to understand the

realistic color capabilities and expectations one should have of these systems

CMYK is a 4-color printing process using 3 subtractive color primaries with black cyan

magenta and yellow The color limitations of CMYK lie in the difficulty to reproduce bright reds greens and blues as well as many of the colors required by the textile

industry The CMYK process is improved by including extra colors that cannot bereproduced by dithering or mixing cyan magenta and yellow

Hexachromereg is a 6-color process printing system developed by Pantone Inc to addressthis issue In the core of Hexachrome orange and green inks have been added to

modified CMYK inks These additional colors help to reproduce more brilliant

continuous-tone images Pantone states that the Hexachrome system is capable of accurately reproducing over 90 of the Pantone Matching Systemreg Colors - almost

twice the number that can be obtained using CMYK process printing

The strongest complaints about digitally printed fabric from the textile industry are the

visible dither of colors and limited color gamuts compared to traditional textile screen printing With the introduction of 7 8 and even 12-color digital printers into the market

these systems come closer to achieving the results desired by the textile industry As a

general rule the greater the number of colors (not printheads) that are in a printer thelarger the number of colors that can be reproduced For example a 12-color printer with

10 individual colors and 2 light shades

will provide a much larger color gamut

than a 12-color printer using CMYK with light shades It is important

however to have a balance of colorantsto light shades to eliminate visibledither When using textile inks such as

reactive acid or disperse the full

potential of these color spaces are notrealized until the colors have reacted

with the fabric which occurs during

post-processing such as steaming and

washing

The hardware and ink options available

to the textile industry are a reflection of a growing market that has yet to develop any standards As an example Mimaki and

Mutoh printers are available in versions that support both CMYK and Hexachromereg

color systems The Mimaki can be configured with any 6 or 7 colors as well as CMYK with light shades or in Hexachrome DGS offers the Luxor 7 which is a Mimaki printer

that supports three different inksets using CMYK with special colors such as CMYK +

(blue + green + gold) CMYK + (blue + gray + gold) CMYK + (C light + M light + K light) In addition the ColorSpan 12 color printers can be configured as either CMYK

Pantonersquos Representation of Hexachrome vs

CMYK color gamuts

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 39

with light shades of cyan and magenta or use an 8 or 12 color textile inkset The inks

determine the color space but the RIP drives and manages those colors

Digital textile printers are developed tested and marketed with the use of specific inksets

in co-operation with ink vendors offering inks specially formulated for the textile market

While established users such as fine artists and graphic designers have been known tostray from these established formulas in hopes of finding their unique niche in the

market playing with ink chemistries and established inkhardware formulas is not for the

faint at heart Nor is it advisable for companies under tight timelines

12-Color Reactive Ink Set Color Gamut showing enhanced color space provided

by steaming and washing

Graphic arts RIPs and color management systems support the SWOP color standard for

Web-Offset Printing the color reproduction standard for the digital graphics printing

industry Because this standard uses CMYK process color SWOP is inappropriate as acolor reproduction standard for the textile printing industry which has used multiple spot

colors in conventional printing

Color system ndashan overview

To understand all types of process color systems we will look into the process

involved in printing with the CMYK color model in detail

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 49

CMYK color model referred to as process color or four color is a subtractive color

model used in color printing also used to describe the printing process itself CMYK

refers to the four inks used in most color printing cyan magenta yellow and black

Some sources suggest that the ldquoKrdquo in CMYK comes from the last letter in black and

was chosen because B already means blue The CMYK model works by partially or entirely masking certain colors on the typically white background (that is absorbing

particular wavelengths of light) Such a model is called subtractive because inksldquosubtractrdquo brightness from white

Cyan magenta

yellow and key

(black)

Layers of simulated

glass show how semi-

transparent layers of color combine on

paper into spectrum of

CMY colors

Two graphic techniques are required to prepare images for four-color printing andscreening or half toning These steps make possible the creation of printing plates

that can transfer color impressions to paper on printing presses based on the principles of lithography

Color separation process

The process of color separation starts by separating the original artwork into red green

and blue components (for example by a digital scanner) The next step is to invert each of these separations When a negative image of the red component is produced the resulting

image represents the cyan component of the image Likewise negatives are produced of

the green and blue components to produce magenta and yellow separations respectivelyThis is done because cyan magenta and yellow are subtractive primaries which each

represent two of the three additive primaries (RGB) after one additive primary has been

subtracted from white light

Cyan magenta and yellow are the three basic colors used for color reproduction Whenthese three colors are variously used in printing the result should be a reasonable

reproduction of the original but in practice this is not the case Due to limitations in the

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 29

Process Color Systems

Looking at the different process color printing systems will help to understand the

realistic color capabilities and expectations one should have of these systems

CMYK is a 4-color printing process using 3 subtractive color primaries with black cyan

magenta and yellow The color limitations of CMYK lie in the difficulty to reproduce bright reds greens and blues as well as many of the colors required by the textile

industry The CMYK process is improved by including extra colors that cannot bereproduced by dithering or mixing cyan magenta and yellow

Hexachromereg is a 6-color process printing system developed by Pantone Inc to addressthis issue In the core of Hexachrome orange and green inks have been added to

modified CMYK inks These additional colors help to reproduce more brilliant

continuous-tone images Pantone states that the Hexachrome system is capable of accurately reproducing over 90 of the Pantone Matching Systemreg Colors - almost

twice the number that can be obtained using CMYK process printing

The strongest complaints about digitally printed fabric from the textile industry are the

visible dither of colors and limited color gamuts compared to traditional textile screen printing With the introduction of 7 8 and even 12-color digital printers into the market

these systems come closer to achieving the results desired by the textile industry As a

general rule the greater the number of colors (not printheads) that are in a printer thelarger the number of colors that can be reproduced For example a 12-color printer with

10 individual colors and 2 light shades

will provide a much larger color gamut

than a 12-color printer using CMYK with light shades It is important

however to have a balance of colorantsto light shades to eliminate visibledither When using textile inks such as

reactive acid or disperse the full

potential of these color spaces are notrealized until the colors have reacted

with the fabric which occurs during

post-processing such as steaming and

washing

The hardware and ink options available

to the textile industry are a reflection of a growing market that has yet to develop any standards As an example Mimaki and

Mutoh printers are available in versions that support both CMYK and Hexachromereg

color systems The Mimaki can be configured with any 6 or 7 colors as well as CMYK with light shades or in Hexachrome DGS offers the Luxor 7 which is a Mimaki printer

that supports three different inksets using CMYK with special colors such as CMYK +

(blue + green + gold) CMYK + (blue + gray + gold) CMYK + (C light + M light + K light) In addition the ColorSpan 12 color printers can be configured as either CMYK

Pantonersquos Representation of Hexachrome vs

CMYK color gamuts

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 39

with light shades of cyan and magenta or use an 8 or 12 color textile inkset The inks

determine the color space but the RIP drives and manages those colors

Digital textile printers are developed tested and marketed with the use of specific inksets

in co-operation with ink vendors offering inks specially formulated for the textile market

While established users such as fine artists and graphic designers have been known tostray from these established formulas in hopes of finding their unique niche in the

market playing with ink chemistries and established inkhardware formulas is not for the

faint at heart Nor is it advisable for companies under tight timelines

12-Color Reactive Ink Set Color Gamut showing enhanced color space provided

by steaming and washing

Graphic arts RIPs and color management systems support the SWOP color standard for

Web-Offset Printing the color reproduction standard for the digital graphics printing

industry Because this standard uses CMYK process color SWOP is inappropriate as acolor reproduction standard for the textile printing industry which has used multiple spot

colors in conventional printing

Color system ndashan overview

To understand all types of process color systems we will look into the process

involved in printing with the CMYK color model in detail

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 49

CMYK color model referred to as process color or four color is a subtractive color

model used in color printing also used to describe the printing process itself CMYK

refers to the four inks used in most color printing cyan magenta yellow and black

Some sources suggest that the ldquoKrdquo in CMYK comes from the last letter in black and

was chosen because B already means blue The CMYK model works by partially or entirely masking certain colors on the typically white background (that is absorbing

particular wavelengths of light) Such a model is called subtractive because inksldquosubtractrdquo brightness from white

Cyan magenta

yellow and key

(black)

Layers of simulated

glass show how semi-

transparent layers of color combine on

paper into spectrum of

CMY colors

Two graphic techniques are required to prepare images for four-color printing andscreening or half toning These steps make possible the creation of printing plates

that can transfer color impressions to paper on printing presses based on the principles of lithography

Color separation process

The process of color separation starts by separating the original artwork into red green

and blue components (for example by a digital scanner) The next step is to invert each of these separations When a negative image of the red component is produced the resulting

image represents the cyan component of the image Likewise negatives are produced of

the green and blue components to produce magenta and yellow separations respectivelyThis is done because cyan magenta and yellow are subtractive primaries which each

represent two of the three additive primaries (RGB) after one additive primary has been

subtracted from white light

Cyan magenta and yellow are the three basic colors used for color reproduction Whenthese three colors are variously used in printing the result should be a reasonable

reproduction of the original but in practice this is not the case Due to limitations in the

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 39

with light shades of cyan and magenta or use an 8 or 12 color textile inkset The inks

determine the color space but the RIP drives and manages those colors

Digital textile printers are developed tested and marketed with the use of specific inksets

in co-operation with ink vendors offering inks specially formulated for the textile market

While established users such as fine artists and graphic designers have been known tostray from these established formulas in hopes of finding their unique niche in the

market playing with ink chemistries and established inkhardware formulas is not for the

faint at heart Nor is it advisable for companies under tight timelines

12-Color Reactive Ink Set Color Gamut showing enhanced color space provided

by steaming and washing

Graphic arts RIPs and color management systems support the SWOP color standard for

Web-Offset Printing the color reproduction standard for the digital graphics printing

industry Because this standard uses CMYK process color SWOP is inappropriate as acolor reproduction standard for the textile printing industry which has used multiple spot

colors in conventional printing

Color system ndashan overview

To understand all types of process color systems we will look into the process

involved in printing with the CMYK color model in detail

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 49

CMYK color model referred to as process color or four color is a subtractive color

model used in color printing also used to describe the printing process itself CMYK

refers to the four inks used in most color printing cyan magenta yellow and black

Some sources suggest that the ldquoKrdquo in CMYK comes from the last letter in black and

was chosen because B already means blue The CMYK model works by partially or entirely masking certain colors on the typically white background (that is absorbing

particular wavelengths of light) Such a model is called subtractive because inksldquosubtractrdquo brightness from white

Cyan magenta

yellow and key

(black)

Layers of simulated

glass show how semi-

transparent layers of color combine on

paper into spectrum of

CMY colors

Two graphic techniques are required to prepare images for four-color printing andscreening or half toning These steps make possible the creation of printing plates

that can transfer color impressions to paper on printing presses based on the principles of lithography

Color separation process

The process of color separation starts by separating the original artwork into red green

and blue components (for example by a digital scanner) The next step is to invert each of these separations When a negative image of the red component is produced the resulting

image represents the cyan component of the image Likewise negatives are produced of

the green and blue components to produce magenta and yellow separations respectivelyThis is done because cyan magenta and yellow are subtractive primaries which each

represent two of the three additive primaries (RGB) after one additive primary has been

subtracted from white light

Cyan magenta and yellow are the three basic colors used for color reproduction Whenthese three colors are variously used in printing the result should be a reasonable

reproduction of the original but in practice this is not the case Due to limitations in the

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 49

CMYK color model referred to as process color or four color is a subtractive color

model used in color printing also used to describe the printing process itself CMYK

refers to the four inks used in most color printing cyan magenta yellow and black

Some sources suggest that the ldquoKrdquo in CMYK comes from the last letter in black and

was chosen because B already means blue The CMYK model works by partially or entirely masking certain colors on the typically white background (that is absorbing

particular wavelengths of light) Such a model is called subtractive because inksldquosubtractrdquo brightness from white

Cyan magenta

yellow and key

(black)

Layers of simulated

glass show how semi-

transparent layers of color combine on

paper into spectrum of

CMY colors

Two graphic techniques are required to prepare images for four-color printing andscreening or half toning These steps make possible the creation of printing plates

that can transfer color impressions to paper on printing presses based on the principles of lithography

Color separation process

The process of color separation starts by separating the original artwork into red green

and blue components (for example by a digital scanner) The next step is to invert each of these separations When a negative image of the red component is produced the resulting

image represents the cyan component of the image Likewise negatives are produced of

the green and blue components to produce magenta and yellow separations respectivelyThis is done because cyan magenta and yellow are subtractive primaries which each

represent two of the three additive primaries (RGB) after one additive primary has been

subtracted from white light

Cyan magenta and yellow are the three basic colors used for color reproduction Whenthese three colors are variously used in printing the result should be a reasonable

reproduction of the original but in practice this is not the case Due to limitations in the

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 59

inks the darker colors are dirty and muddied To resolve this a black separation is also

created which improves the shadow and contrast of the image Numerous techniques

exist to derive this black separation from the original image these include greycomponent replacement under color removal and under color addition This printing

technique is referred to as CMYK (the K being short for key In this case the key

color is black) Todays digital printing methods do not have the restriction of a singlecolor space that traditional CMYK processes do Many presses can print from files that

were ripped with images using either RGB or CMYK modes The color reproduction

abilities of a particular color space can vary the process of obtaining accurate colorswithin a color model is called color matching

Screening

Inks used in color printing presses are semi-transparent and can be printed on top of each

other to produce different hues For example green results from printing yellow and cyan

inks on top of each other However a printing press cannot vary the amount of ink

applied to particular picture areas except through screening a process that representslighter shades as tiny dots rather than solid areas of ink This is analogous to mixing

white paint into a color to lighten it except the white is the paper itself In process color printing the screened image or halftone for each ink color is printed in succession The

screen grids are set at different angles and the dots therefore create tiny rosettes which

through a kind of optical illusion appear to form a continuous-tone image You can viewthe halftoning which enables printed images by examining a printed picture under

magnification

Traditionally halftone screens were generated by inked lines on two sheets of glass that

were cemented together at right angles Each of the color separation films were then

exposed through these screens The resulting high-contrast image once processed haddots of varying diameter depending on the amount of exposure that area received which

was modulated by the grayscale separation film image

The glass screens were made obsolete by high-contrast films where the halftone dotswere exposed with the separation film This in turn was replaced by a process where the

halftones are electronically generated directly on the film with a laser Most recently

computer to plate (CTP) technology has allowed printers to bypass the film portion of the process entirely CTP images the dots directly on the printing plate with a laser

saving money increasing quality (by reducing the repeated generations) reducing lead-

times and saving the environment from toxic film-processing chemicals

Screens with a frequency of 60 to 120 lines per inch (lpi) reproduce color photographsin newspapers The coarser the screen (lower frequency) the lower the quality of the

printed image Highly absorbent newsprint requires a lower screen frequency than less-

absorbent coated paper stock used in magazines and books where screen frequencies of

133 to 200 lpi and higher are used

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 69

The measure of how much an ink dot spreads and becomes larger on paper is called dot

gain This phenomenon must be accounted for in photographic or digital preparation of

screened images Dot gain is higher on more absorbent uncoated paper stock such asnewsprint

Digital textile printing color management software must answer three key questionsFirst what is the color gamut (range of printable colors) of the system taking into

account the printer inks and fabric used Are the desired colors inside the digital printerrsquoscolor gamut And last but not least how can the system produce all of the colors that are

within the color gamut

It is important to understand which colors are attainable within the limits of specific

printers and ink sets If a printer is incapable of producing a desired color no amount of

color management can make it possible In addition there are some colors that can bedisplayed on an RGB monitor but not printable using a CMYK device and vice verse

(CMYK representing the Cyan Magenta Yellow and Black inks used in process color

printing)

Some of the first digital printing systems introduced to the textile industry using CMYK

process printing were originally developed for the graphics and paper printing industries

These systems were not well received because the color gamut obtainable in CMYK isconsiderably smaller than the gamut of spot color inks used in conventional rotary screen

printing of textiles

Defining and Profiling Color

CIE Lab color space is one of the color standards used by the textile industry The

CIE International Commission on Lighting realized that every color the human eye perceives could be defined using three numbers L indicates luminosity lightness fromwhite to black The a and b are the chromaticity coordinates that indicate color

directions +a is the red direction -a is the green direction +b is the yellow direction

and ndashb is the blue direction The center is achromatic hues of gray As the a and bvalues increase and the point moves out from the center the chroma or purity of the color

increases The pythagorean distance between two color points plotted in the color space

relates to the visual color difference between those two points In this way color

variation between points and a standard may be expressed using numbers

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 79

Color management and RIP(Raster Image Processors) software manage color by creating

profiles or characterizations specific to the printer ink fabric and any post-processing

such as steaming and washing All of these variables have an impact on color and eachvariation must be profiled to insure accurate color match When a design is printed a

profile is selected based on

the printerinkmediacombination to insure that

the colors in the original

design or target colors matchthe digitally printed output

The process of creating a

profile or characterization of a digital printer begins by

printing out a linearization

file of the inks in the printer

typically from 0-255saturation Data on ink

density limits can begathered at this stage as well

These color targets are

measured by a

spectrophotometer (See thetechexchangecom color

library for more articles specific to the color measurement of textiles) Next a number of

color targets are printed and measured to map the color space of printable colors Fromall of these data points an algorithm is used to calculate the color space and the profile is

complete

Various software packages offer different levels of profiling capabilities from supporting

standard ICC profiles created in third-party profiling software to vendor supplied

profiles to end user capability to create custom profiles using proprietary color systemsThe International Color Consortium (ICC) color profile is a standard profile format that

characterizes the color-reproduction capabilities or color gamut of devices such as

scanners digital cameras monitors and digital printers For a glossary of color science

terminology go to httpwwwuicedu~hilbertGlossaryhtml

The price points of various software packages are often determined by the level of

profiling and color management capabilities For instance a RIP without profilingcapability may be less expensive than one that uses proprietary systems to enable the end

user to generate profiles These options offer color management of digital printing

systems to customers who may not want to delve into profiling themselves

What is a color management system

Diagram of CIE Lab Color Space

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 89

A system that transforms data encoded for one device (such as scanner RGB) into that for

another device (such as printer CMYK) in such a way that it reproduces on print the same

colours as those scanned Where exact colour matching is not possible the result should be a pleasing approximation to the original colours In general the term colour

management system is usually reserved for those systems that use the internationally

accepted CIE system of colour measurement as a reference

Software Solutions

Textile specific software is needed to handle textile design images including flat and

continuous tone designs separation files in addition to color management Important

software features for digital printing of textiles include

bull Accept textile industry file formats from CAD design and screen separation programs CST MST PUB GRT SEP SCN XPF etc

bull Accept common graphic file formats TIFF Indexed 8 bit TIFF PSD EPS AI

BMP TGA etcbull Print Layout functions such as step amp repeat design coordinates and colorways

color chips multi-image placement scaling rotating spooling or batching etc

bull Manage expanded ink sets beyond CMYK depending upon printer

bull Ink control functions Manage higher ink densities required for color saturation of fabric

bull Color catalogs color palettes andor Pantone Textile Color System

bull Profiling supplied by vendor or custom profiling capability

bull Color gamut visualization and comparison to see if target color is attainable

bull Screen Print Simulation features if digital output needs to match to production

bull Capability to link color data to the textile millrsquos color kitchen

Digitally printed fabric is often seen as too good to be reproduced by traditional screen printing techniques It is helpful to have screen simulation features to bridge the gap

between digital and screen printed fabrics Several software vendors have incorporated

features useful in simulating and matching to screen printed production fabric such assimulating screen resolution raster simulation or screen mesh size color mixing color

overprinting and color trapping incorporating gradation curves for tonal separations and

even profiling the textile printing millrsquos color space

The color management and RIP software options available to the textile industry reflect a

growing market and growing acceptance of digitally printed fabric for proofing

sampling and short-run production It is no longer enough to be able to print fabricdigitally the industry is requiring color matching and management throughout the

complete design workflow from scanning to calibrated monitors spectrophotometers to

the digital printer Future hardware and software developments for the textile industry

may include combinations of spot and process printing systems and customization of awider range of ink colors that can be selected depending upon the color space

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 99

requirements of the design to be printed With all of these future developments the color

management and RIP software will be the engine that drives these systems

Conversion

Since RGB and CMYK spaces are both device-dependent spaces there is no simple or general conversion formula that converts between them Conversions are generally done

through color management systems using color profiles that describe the spaces being

converted Nevertheless the conversions cannot be exact since these spaces have verydifferent gamuts

The problem of computing a colorimetric estimate of the color that results from printing

various combinations of ink has been addressed by many scientists[9] A general method

that has emerged for the case of halftone printing is to treat each tiny overlap of color dots as one of 8 (combinations of CMY) or of 16 (combinations of CMYK) colors which

in this context are known as Neugebauer primaries The resultant color would be an area-

weighted colorimetric combination of these primary colors except that the YulendashNielseneffect (dot gain) of scattered light between and within the areas complicates the physics

and the analysis empirical formulas for such analysis have been developed in terms of

detailed dye combination absorption spectra and empirical parameters[9]

832019 color work for printing

httpslidepdfcomreaderfullcolor-work-for-printing 99

requirements of the design to be printed With all of these future developments the color

management and RIP software will be the engine that drives these systems

Conversion

Since RGB and CMYK spaces are both device-dependent spaces there is no simple or general conversion formula that converts between them Conversions are generally done

through color management systems using color profiles that describe the spaces being

converted Nevertheless the conversions cannot be exact since these spaces have verydifferent gamuts

The problem of computing a colorimetric estimate of the color that results from printing

various combinations of ink has been addressed by many scientists[9] A general method

that has emerged for the case of halftone printing is to treat each tiny overlap of color dots as one of 8 (combinations of CMY) or of 16 (combinations of CMYK) colors which

in this context are known as Neugebauer primaries The resultant color would be an area-

weighted colorimetric combination of these primary colors except that the YulendashNielseneffect (dot gain) of scattered light between and within the areas complicates the physics

and the analysis empirical formulas for such analysis have been developed in terms of

detailed dye combination absorption spectra and empirical parameters[9]