Tweaking The Random Colour Generator

I start with 22 colours sorted into seven colour groups (red, yellow, blue, orange, green, violet and brown).  The spreadsheet picks one of the 22 at random: all are signed equal probability.

Before picking a second colour, I eliminate all the other colours in the same colour group as the first colour.  So if my first colour’s Prussian blue, I eliminate all other blues.  The spreadsheet then picks out a second colour, assigning equal probabilities to all other colours.

None of that’s changed.  What I’ve made a change to is the procedure for picking a third colour.  For my first ten dash & splash paintings, I would pick a third random colour after eliminating all colours in the same groups as the first two colours and assigning equal probabilities to all the remaining colours.  The problem I found with this was that the spreadsheet would occasionally throw out ugly triads: the village hall painting I was presented with a blue, a brown and a violet and  the painting inside the Tuck Inn, I was given a green, a yellow and a brown.  When you stop to think about it, you realise there are some combinations of the three colour families that work and some that don’t.

So I’ve created a table of the 35 possible triads with a column of ones and zeros to tell the spreadsheet whether that particular combination is allowed.  So now, the way things work is that:

– the first and second colours are chosen the same way as before

– for the third colour, the spreadsheet eliminates all the colours in the same groups as the first two colours and all colours in groups that are not allowed to form triads with the groups for the first two colours.  Then  it chooses one of the remaining colours, assigning an equal probability to each one.

The table of colours may get tweaked over time if I find certain combinations don’t work or decide to bring back previously banned triads: all I need to do is to change the ones and zeros.

One weird combination worth mentioning is brown, yellow and red.  It’s a combination that I’m allowing, despite the lack of any blue within the set.  This is actually the only combination that includes both red and brown: without it the spreadsheet would be left with no balls in the bag if the first two colours picked were a red and a brown.  I just don’t see blue, violet or green working with red and brown: things would get too dark and/or muddy.  Of course if I want to ban all red/brown combinations, I can just reclassify burnt sienna and burnt umber as reds, leaving me with five reds and no browns.

Anyway, I’m glad I got that off my chest.  If any future dash & splashes are flops, I won’t be able to blame the iPad.