Blog 35 : Colour matters – Understanding muddy mixes!

I have heard this question asked so many times online and by students. There is a simple answer and some technical information which I will write for you all now.

Rule 1 : Whenever you use a three-way mix of primary pigments remember this little trick. Use mostly two of the primaries and only add a little of the third. This avoids muddiness and keeps the mix brighter.

Rule 2: Use primary pigments that are less saturated. That is, those pigments which are closer to the true primary red, blue or yellow. These mixes will be instantly brighter and less muted.

Rule 3: More saturated primary pigments make more muted, earthy mixes.

Recognising warm and cool, muted and bright pigments will help you to assess and mix more accurate colours. The basic colour wheel alone does not explain this clearly so read on…

Basic colour wheel

Look at the diagram I made which is based on the Moses Harris colour wheel (Moses Harris 1769 -1776, ‘The Natural System of Colours’). There are 18 sections on this wheel, each section showing how each colour mutes as it gets closer to the centre from the brightest ring. Tints from the brightest ring are lightened as it would by adding water to watercolour. The in between sections between the primary and tertiary colours are biased. For example yellow/orange – a yellow biased orange, green/yellow – a green biased yellow.

Each of these section mute down until eventually meeting black at the centre. The blue/purple is a mauve area and the purple/blue is the violet area. Looking at the left side between red and yellow sections you can see where Yellow Ochre, Burnt Sienna, Raw Sienna and Burnt Umber pigments come from.

Colour wheel by Jackie Isard bases on the Moses Harris colour wheel, 1769 - 1776 'The Natural Systen of Colours'

Every colour pigment that you buy can have a warm or cool, muted or earthy appearance. For example, a red like Burnt Sienna or Indian Red are definitely more muted reds and nearer to the middle of the diagram. A green/yellow or yellow/green is warm when compared to a cooler green but sits on the cool side of the wheel. This is a tad confusing! We need to look at this a different way and I will explain why.

Notice the ‘brightest ring’ for yellow, red and blue (not the purple, green or orange area as this is essentially two primaries mixed together – remember rule 1) marked on the concentric circles. These are the pigments that will make the brightest mixes. However, the orange, green and purple/violet pigments in this area will make brighter mixes than those below this line with a very little of the third primary added (rule 1). Any colour that moves towards the centre from this line will make earthy, muted and darker tones. Apply this rule when choosing pigments and you will understand why some mixes can become very muddy!

A red within the orange/red and red/orange sections are warm reds, having an orange bias. The true primary red sits in the next segment. After this the segments move towards the purple/violet spectrum, making them cooler as they take on a violet bias. All reds in the deepening area towards the centre become more muted and earthy, like Burnt Sienna, Permanent Alizarin Crimson, Permanent Carmine, Indian Red, Perylene Maroon etc.

As the brightest ring red moves towards the violet (purple) spectrum it becomes a cool red, like W&N Quinacridone Magenta (PR122) or Permanent Rose (PV19). Paint Permanent Rose next to Quinacridone Red and you will see it has a cool violet bias. Paint the same pigment next to Quinacridone Magenta and Permanent Rose will appear warmer as the violet bias is not so extreme. A blue with a green bias, when mixed, will behave as if a little yellow has been added to the mix. A blue with a violet bias, when mixed, will behave as if some red has been added. Recognising biases will help you to choose the right pigments to make a brighter mix or a more muted one.

There is a pigment comparison list later in this blog which gives the names of pigments across three other brands which are similar or the same as the W&N names I refer to here.

Both bright and muted mixes are relevant in botanical painting. Shadow tones and deeper richer colours will need to be muted a little to create depth and form. For example, adding a little more red and blue to your green mix to make the shadow edge tones. It really pays to get to know your palette of pigments to see which ones will create the tone you need – muted or bright!

It is known that red, yellow and blue will make brown or a black mixed in the right proportions. Mixing browns with warm or cool brighter pigments will give different results. There are many tones of brown. Using different sets of primaries will create many different brown mixes. This also applies to black. A true rich black or a cool cold black. There are even different blacks!

Red, yellow and blue = black or brown image

Remembering here rule 1 at the beginning of this blog. The more of the third primary you add to a mix, the more muted it becomes. The secret of bright mixes is not only this but also depends on the saturation of the pigment. Selecting colours on the ‘brightest ring’ of the diagram will be more saturated.

Saturation: These are the colours that are closest to the absolute primary colour. For instance, Quinacridone Red and Winsor Red are true primary reds. Permanent Rose and Quinacridone Magenta will be less saturated as they are closer to the violet (purple) spectrum. Winsor Lemon or Transparent Yellow are true primary pigments. Winsor Yellow or Indian Yellow are heading towards the orange spectrum so will be less saturated.

Tertiary colours

Tertiary colours image

Tertiary colours are orange, green and purple (violet). Anything you add to a secondary colour will mute or become earthy in tone. This is because the secondary colour is already two primaries; red and yellow (orange), blue and yellow (green), red and blue (violet).

Intensity

Pigment strength, brightness, or purity. Some pigment intensity can be very high, therefore less pigment is needed when mixing. This is especially so with ‘permanent’ pigments. Quinacridone Red, Cobalt Blue, Viridian, Winsor Lemon, Raw Sienna are all weaker pigments, so you’ll need to add more to a mix if mixing with a high intensity pigment. Staining pigments usually have a very high intensity of pigment. Below is a chart that shows some pigments that will dull or brighten a mix and below this are some anomalies that do make bright mixes despite being biased.

Colour intensity and brightness chart by Jackie Isard

Anomalies

Colour anomalies chart by Jackie Isard

All pigments in my palette are lightfast, transparent or semi-transparent with a good permanency rating. Transparency ensures vibrancy and translucence. Permanency and lightfastness ensures your painting will last a life time.

Pigments with the same name do not translate across brands. Never think this is so. Colour with the same index numbers do not always translate across brands either. There are two blogs linked below to read more about this.

Index numbers also have variations of scale too. The codes for index numbers is listed here.

PY – Pigment Yellow
PO – Pigment Orange
PR – Pigment Red
PV – Pigment Violet
PB – Pigment Blue
PG – Pigment Green
PBr – Pigment Brown
PBk – Pigment Black

Here’s an example. PB15 is divided into a spectrum of blues within the same index number. Your may see PB15:6 or PB15:3 on tubes of Sennelier Blue watercolour. The green bias version of this blue is PB15:3 (Sennelier Bleu Phthalo Vert) and the red biased version PB15:6 (Sennelier Bleu Phthalo Rouge). So, if you open a tube of a pigment with the same index number as a pigment in another range, it may not be the same ratio when you paint with it!

Pigment brand comparisons

Pigment brand comparisons chart by Jackie Isard

Note: DS has no equivalent to Quinacridone Magenta apart from Opera Rose PR122 but this pigment has the addition of fluorescence and so it will fade in light (fugitive).

Read more in my blogs below.

Jackie Isard's go-yo palette of W&N pigments

I sell an A4 leaflet for £1.50 of my colour diagram featured in this blog. If you would like to buy one please email me at jackieisard@googlemail.com.

Leaflet by Jackie Isard of her dynamic colour wheel

I do hope you found this blog useful and welcome any feedback or questions!

Leave a comment