For Image Reports

Building Bridges between CMYK and RGB Colours – published by Image Reports – the Trade Magazine of Large Format Printers.

There’s a crack in everything. That’s how the light gets in. This is what Leonard Cohen[4] sang.

The crack between electronic Red, Green and Blue [RGB] and printed Cyan, Magenta, Yellow and Black [CMYK] is the way that numbers are treated in mathematics. There is a fundamental difference between producing numbers for these two kinds of colour sets. One is based on the chemistry between colour pigments and materials and the other on the physics of light in the materials of electronic displays such as computers, TV and phones.

So far, there are no conversion algorithms between the two systems. This article introduces possibilities for building bridges between the two systems.Number theory is said to be the queen of mathematics, but a friend of mine asked “Why do numbers need a theory?”The famous physicist Richard Feynman said “It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.”

To match my ‘software-aided thinking’, my ‘experiment’ consists of using prototype software that embodies my mathematical concepts and testing it with meaningful data. ‘Meaningful’ to prove the usefulness of my concepts, convey messages of innovation and ‘demonstrate by Try Before You Buy’.Mathematics is more than theory. It attempts to model physical realities.

But Einstein said “As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.” Metrology, the science of measuring, always caters for uncertainties and probabilities. In contrast, our Smart Knowledge Engine[5] delivers Pixel Accuracy[6].

By way of screenshots, this article demonstrates that and how the numbers that represent Pantone colours along CMYK can be translated into the numbers that show RGB in electronics, while the Wikipedia entry on the CMYK colour model[7] claims that there is no simple or general conversion formula.

My question is: would you want to use our software to help characterise, standardise and translate[8] the colour gamut[9] or spectrum[10]?The answers could be collated into new ‘Digi-Tone landscapes’ that combine ‘paper Pan-Tones’ with other colour charts[11]. There is already a list of reference tools[12] compiled by the International Colour Consortium[13].

We developed Digital Colour Brightness[14] in True Colour 3D[15] as a new way of visualising the numerical representations of digital images. This means we can compare colours visually and we see the ‘numerical inversion’ of White becoming Black and Black becoming White. The numerical comparisons are useful for experts first and the operators supervising automated processes later.By visualising the numerical representation of digital images we have produced a new kind of ‘digital yardstick’ for colours and also for what they represent.

Large format printers will want to think about how this invention could become useful to them. I was particularly attracted to the possibility of exhibition spaces with large electronic displays. Who is in touch with the International Colour Consortium[18] that aims at “making colour seamless between devices and documents”? I was also imagining ‘merchandise’ such as Pantone swatches for professional use and memorabilia of the WOW experience. 


  • outside, large displays show videos[19] of moving objects in True Colour 3D:
    • Logos of the exhibitors;
    • Profiles of speaker photos;
    • Colour matrices of RGB and CMYK;
  • inside, visitors pass through ‘colour portals’:
    • they are immersed by light in particular colours and they choose their ‘comfort factor’;
    • they take away ‘memorable output’ either as 2D or 3D printout or both;
    • statistics about preferred colours add input to the ‘colour of the year[20]’.

Here are the colours of the years from 2000 – 2014 taken from the Wikipedia page – re-visualised ‘normally’ and ‘numerically inverted’.

You will come up with your own ideas for making use of the newly found aspects of turning images into True Colour 3D, with Pixel Accuracy and Digital Colour Brightness as a bridge between electronic RGB and paper based CMYK.Meanwhile, you are invited to visit our Smart Knowledge Engine[21] as work in progress, click on VISUAL 3D on existing files, such as the links above, or add your own images.You can also visit Smart Knowledge Space[22] as the description with galleries of screenshots. Or else email me on























© Copyright Sabine K McNeill 1996 – 2017 

The logo from Re-visualised by our Smart Knowledge Engine[3] on ‘Numerically inverted’
a first step towards general formulae for converting RGB into CMYK and vice versa
The input image from
Our re-visualisation
as a movable object on
Our ‘numerical inversion’
turns White into Black
and Black into White
The input from
Our re-visualisation creates valleys in True Colour 3D[16]: Our ‘numerical inversion’
turns valleys into mountains
and White into Black
One of the images on the home page of
to ‘Set your Imagination Free’:
in ‘True Colour 3D[17]
Numerically inverted’ you see the elephant open his eyes before you, as you tilt the image as a movable object.
White is ‘high’.

Colours show ‘mountains’ of different heights.

Black is ‘high’.

Colours show ‘valleys’
of different depths.

2000 – 2004    
2005 – 2009    
2010 – 2014