I get asked this question all the time. What does ICC profiling do? A lot of people say to me, “It will fix my bad colour, right?” Well, not really. Making a new ICC profile does not fix bad colour – there is more involved here.
An ICC profile by itself by itself does nothing, it is simply a colour description waiting to be used. You need at least two profiles to achieve an outcome. Profiles only work in a transform or conversion – you need a source and a destination profile. e.g. a source profile could be “sRGB” and the destination a CMYK print profile. This means the RGB file with the assigned sRGB profile will be converted to the CMYK space of the destination profile, under the control of the chosen rendering intent – Saturation, Perceptual or Colorimetric. Profiles communicate with each other in a common language, such as “L*a*b*” or “XYZ”.
An ICC profile gives meaning to the RGB or CMYK numbers in a file. For example, a scanner captures RGB information. The scanner RGB ICC profile provides meaning to how the scanner behaves and captures the RGB colour. The profile does not correct how the scanner captures colour it simply describes how the colour is captured. Now if you wanted to display the scanned image correctly you would need to make a monitor ICC profile. Profiles always work in twos!
We have oversimplified it a bit here, as colour management can be complex, but all you have you to do is follow some rules.
C stands for?
Before building a new ICC profile for a scanner, camera, monitor or printer you should calibrate the device first.
Calibrating is the most important step before creating an ICC profile. Calibration is about getting your device into a known, quantifiable and repeatable state.
What does this mean? On a monitor you adjust the brightness and RGB controls until you hit predetermined luminance and colour temperature targets. On an inkjet printer outputting through a RIP, calibration means setting up per channel ink limits, overprint ink limits, CMYK linearisation and grey balance control – it’s about ink media compatibility. Both aforementioned required measurement with an instrument (colorimeter or spectrophotometer) which makes it quantifiable. And if it is quantifiable, then it is repeatable.
After your calibration is complete you can then create your ICC profile.
If your device changes or wanders over time you can re-calibrate it back to the known settings and your existing profile will still be valid.
This is the benefit of having a good calibration process in place.
Every device is unique
Every device colour behavior is going to be different, which is why calibration is so important. Especially if you have multiple devices that you want to simulate to a common output colour space – think ISO Coated v2 (Fogra 39) or PSO Coated v3 (Fogra 51).
Every device colour behavior is going to be different, which is why calibration is so important. Especially if you have multiple devices that you want to simulate to a common output colour space – think ISO Coated v2 (Fogra 39) or PSO Coated v3 (Fogra 51).
Colour management is not perfect – there are device and colour limitations. And sometimes our expectations are set unrealistically too high. Colour measurement, human vision and viewing conditions all need to be properly defined, described and explained.
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