What Is Colour Management?

What is Colour Management?

According to the International Colour Consortium (ICC) for short, the industry-standard ICC profiles are used for colour management when it comes to defining the colour of many different production devices, this includes digital cameras, monitors, printers, and proofers. Colours cannot be expected to match every time from one device to another, due to the standard plug-and-play nature of desktop publishing, especially when they are using different colourant systems (e.g. RGB vs CMYK).

The colour-managed workflow attempts to match the required colour as accurately as possible among different device - given a set of ICC profiles and workflow software, such as Photoshop, Illustrator, or a Raster Image Processor (RIP).

While there are no excuses for inaccurate colours, in most jobs there are colours that are critical and others that are not as critical. When it comes to corporate and brand colours, they are very important and requires a lot of time and effort in getting them right is worthwhile, as colour accuracy have always been an important key factor when it comes to designing and printing where it is essential.

Why Is Colour Management So Important?

Some of the commonly cited reasons for interest in colour management includes:

• Consistency
  An important key word in the printing industry, consistency means having the ability to get the colour accurately and correctly the first time and every time. And, also to get the colour that matches throughout a print run and from run to run.
• Soft Proofing
  Monitor previews that match printed output are referred to as soft proofs. Contrary to popular belief, a calibrated monitor does not necessarily guarantee a match with printed colour. It only shows that “what you see is what’s in the file”. For accurate soft proofs, both a printer and monitor profile are required, along with a “proofing” or “simulation” workflow.
• Hard Copy Proofs
  Clients often wants to see production prints as proofs that it matches their requirements, when it comes to printing digital, offset, large format, or using any other process. Hard copy proofs refer to pre-printed samples that show how production prints will look. They are generally printed on faster, lower cost, and easier-to-operate printers, such as inkjet, which may not inherently match the production process.

The 4 Cs of Colour Management

There are 4 Cs when it comes to colour management, Consistency, Calibration, Characterization and Conversion.

1. Consistency refers to setting up a device to achieve optimum colour. For an Inkjet printer, these steps could include setting ink limits and total ink coverage for optimum ink usage and colour gamut.
2. Calibration refers to aligning all devices to a known standard or specification. A common standard for inkjet printers is linearization, meaning tones, or halftone dot values, increase in sequence. This ensures consistent performance and images with good contrast and tone separation.
3. Characterization means profiling a device using a profiling program and a colour target that’s printed, captured, or displayed.
4. Conversion for colour to match from one device to another, colours must be converted, or changed in value, to create the match. This conversion is done by the workflow software, whether it’s photoshop or a RIP.

Tools of the Trade

A spectrophotometer is a device that measures light intensity by measuring the wavelength of light. A common practice in the printing industry, application of spectrophotometers measures light absorption. A spectrophotometer will shine a white light onto the sample which then absorbs and reflects back. The reflected light passes through a detector which splits the light into separate wavelength intervals, and outputs those values to the device itself or an attached computer. The reflectance of a sample is expressed as a fraction or percentage.

Essentially, a spectrophotometer works by shining a light onto the substrate and then measures the light waves reflected back.

In addition, a spectrophotometer is a sophisticated instrument that reads the full spectrum of colour, from 380-720nm in wavelength. Readings are generally at 10nm increments, provide a true “fingerprint” of colour. This information can be used for profiling both monitors and printers. Spectrophotometers are available in two types: x-scanning or semi-automated instruments.

Manual colour reading instruments are only able to process one colour patch at a time are not very efficient for reading test charts with hundreds or even thousands of colours. Digital spectrophotometers are designed to scan rows of colours within a few minutes. They are useful for profiling up to several printers per day.

Utilising a Digital Spectrophotometer

Colour measurements with the spectrophotometer are performed by measuring the spectral reflectance of the object.

Colour measurement calculations are based on the spectral distribution of the illumination, the spectral reflectance obtained for the object, and the colour-matching function. Its result expresses the colour as a numeric value.

Illumination of spectral distributions and colour matching function values are stored in the colour measurement software to obtain the values when spectral reflectance spectrum is measured.

Several conditions are set in order to measure colour. These conditions comprise of the illumination and Viewfield (viewing angle). Settings for the illumination are required, as the colour varies according to the illumination on the sample. The Viewfield must also be set, as the colour appears different when a sample is observed close-up or from a distance. If the parameter settings are changed while reading measuring colour, the displayed values will change immediately.

EPSON SD-10 Spectrophotometer

Epson simplifies colour matching by going digital with its own brand-new SD-10 Spectrophotometer, Epson’s first colour measuring device is said to be accurate, compact, affordable, and works with a downloadable app to store the data for easy reference in future.

Analogue colour matching has always been a tedious and time-consuming work for designers by matching colours based on human sensory perception instead of numerical output for colour matching accuracy and efficiency.

The Epson SD-10 helps save time, effort and increase productivity by reproducing the closest possible colour value as required by your clients with a simple push of a button.

During print productions, accurate colour matching are often an issue, particularly with corporate logo colours. The SD-10 helps solve problems related to colour matching which were handled by a specifically trained and experienced operator. Anyone can now measure and quantify colours without specialised knowledge, so colours and processes can be standardised for a more effective and efficient work flow.

Lastly, the app also identifies similar colours of measured colours, colour scheme examples and complementary colours, and similar PANTONE® colours.

Author: Adren Loy