Colour in process diagrams

Skore, TIBCO Nimbus and Elements all come with a standard style sheet and the ability to customise it.  So if you need to make the style reflect your corporate colour scheme, you can.  But just because you can, doesn’t mean you should.  The fact is, processes have a much longer shelf life than corporate branding guidelines, especially when you factor in mergers, acquisitions and divestitures. 

Good Practice

  • Stick with the default – what harm can it do? (As it happens, none, as we will see later.)
  • If you have to change it, keep it neutral so you don’t have to rework it when corporate branding changes.
  • Make sure it meets accessibility requirements.

Those principles may seem absurdly simple, but that’s for a reason.  Read on…

Colour as a metaphor on diagrams

Calling out objects on a diagram using colour seems, on the face of it, like it could be useful.  But the meaning of your metaphor:

  • needs to be intuitive and obvious without needing a key / legend
  • must not rely on colour alone, for accessibility reasons

e.g. makes extensive use of red, yellow and green alert boxes because those colours are a universal metaphor.


5% of the population has some form of colour blindness and red/green is the most common.  Traffic signals overcome this problem using position. That doesn’t work in our use case…


… we use an icon to indicate the type of alert.  The graphic shows what would happen if we relied on colour alone.  By using an icon we meet the needs of all sighted people.


Not convinced?

Here’s a test for regular sighted people.  The following four activity boxes are, randomly:

  • Red
  • Orange
  • Green
  • Elements default blue box / grey line colour scheme

Your job is to decide which is which.  Easy, right? Not quite.

To make things a little more complicated they are shown through the lens of someone with red colour blindness.  Can you tell which box and line are which?  I’ll give you a clue.  Box 2 is Elements default colour.

Not easy being colour blind is it?

I’ll put you out of your misery…

Whoa, so red and green were intended to convey meanings that were poles apart, but the colours are almost indistinguishable to a colour blind person.  That can’t be good can it?

And just to prove how little colour matters, look at the social bar top right of this screen.  You recognise them for what they are, yes?  No colours at all.

Why bother with colour?

You’ll notice that box 2 is almost identical in both the images above.  After all that trouble to change the colours,  the metaphor has flopped; and the default scheme turns out to be the least affected.

And red / orange / green limits you to just three options.  What if you need more? As you can see from the next graphic, the line text makes it clear what’s special about a particular line – four options in this case – without using colour at all.  If I was to use colour as well, I’d have to pick a different shade of one of the existing colours, which would add to the colour-blind person’s confusion.


These examples demonstrate that, when you need to emphasise some aspect of your process,  colour is of secondary importance. Text, icons and position are much more effective at conveying the message. 

If it takes a lot of effort to do it, and achieves no useful purpose, why bother?  You would be allowing style to get in the way of substance, while confusing the hell out of 5% of your employees.

And it’s also the reason why you want to avoid adopting a corporate brand colour scheme on your diagrams.  Red and yellow may look good on the side of a courier’s truck but as a colour scheme for boxes and lines? Not so much.




  1. I completely agree, Paul! It’s inevitable at all client engagements that at least one person will suggest, as if nobody has ever thought of it before, that we use colors to distinguish different functions or groups who have the responsibility for an activity. Or maybe they want to use color to indicate different phases of a project. I generally manage to convince them otherwise. On the few occasions when I’ve succumbed to pressure, the coloring exercise was soon shown to have little value, and possibly negative value as, without a legend (as you point out), people are confused about what the colors mean.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes:

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>