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A Blue Lemon: Why Understanding Colour is the Key to Realism

August 19, 2016 By: Paul31 Comments

lemon-study-featured

“Paint what you see, not what you know”.

I’m sure you’ve heard that before.

And most of the time, it’s pretty good advice. But it’s not the whole picture. Why? Because you can’t always trust what you see.

What we see is a result of what our perceptual systems show us, processed through our previous experience and our knowledge. It’s filtered. What we see is affected by what we know. You can’t turn that off. It’s the reason visual illusions like this work.

The Yellow lines are the same length. Click on the name at bottom of pictue for an explanation.

So what we know can cause us to interpret what we see incorrectly.

Thankfully, the converse is true: what we know can help us to interpret what we see better. It can help us be fooled less easily – as long as we’ve taken the time to gather some better understanding.

A good example of this is modelling factors

Modeling factors

You may have come across the modeling factors of form before. It’s a very useful bit of knowledge that helps with making objects in drawings or paintings look three dimensional.

modeling-factors

You may have seen diagram like this with more factors. I’ve missed out the ones to do with the cast shadow and also the terminator – the point where the half tone turns into shadow. Why I’ve done that will become clear shortly.

But you get the idea. The modelling factors describe the way value changes across an object depending on how the light falls on it. And they’re very useful to know because they can help you interpret what you see. They can help you make more realistic drawings and paintings.

However, as shown here they describe value only. They don’t tell you anything about how colour changes across a form.

I’ll explain.

How to model form with colour

If you’ve come across Munsell before, you’re probably aware of the three aspects of colour – hue, value and chroma.

If that’s new to you, or you want a quick refresher, click here and I’ll email you a link to a video with a quick overview.

OK, good. So we know what Munsell is. But how does that help us when we’re at the easel?

Well, let’s assume we have a sphere of a single local colour, sitting in a mid-grey shadow box.

5pb-7-8-sphere

That’s a Munsell chip I’m holding there, of exactly the same local colour as the sphere. I know because I mixed up some paint to exactly match the colour of the Munsell chip, and then painted the sphere with it.

So I know exactly what hue, value and chroma the local colour of that sphere is. That’s going to be very important. You’ll see why shortly.

By using a simple colour checker, along with the Munsell chips, we can isolate the colours we see for each modelling factor, like this:

5pb-reflected-light

In the picture above, the colour checker is showing me the colour of the reflected light in the shadow. Now I can mix it exactly.

I can use the same method to nail down the five colours I need for each modelling factors of our blue sphere. They’re all (or almost all) on this page of the Munsell big book:

5pb-page

And here they are, with their respective modelling factors:

5pb-page-colours

All those chips are the same hue, they only vary in chroma and value. The one exception here is the colour of the core shadow, which was slightly warmer – the hue moving around the Munsell hue wheel towards green a little. That’s the only hue change in all these colours.

And that’s worth noting. Almost all the colours across the surface of this sphere are of the same hue. That’s why I’m using Munsell for this, and why it’s so useful that I know the exact hue of the local colour of the sphere (5PB, or 5 Purple Blue, in Munsell terms).

Because that’s how I know that the hue is staying the same across most of the modelling factors of this sphere. The Munsell chips tell me. They’re helping me to understand how the colours change from light to shadow.

The value changes the most, the chroma changes quite a bit (dropping in the highlight and in the shadow) and the hue hardly changes at all. So if you want to get better at painting stuff that looks real, don’t obsess over changes in hue. Look very closely at value and chroma.

Here are those five colours mixed and ready on the palette:

5pb-palette

Now I can paint the sphere 🙂

Painting the Sphere

This is actually a pretty simple process, once the colours have been nailed down and I know, from the modelling factors, where they need to go.

In fact, the hardest part of painting has been done already – judging and mixing the main colours. I just pulled that part out and did it separately, instead of on the fly as I’m painting.

Step 1: Background

First, I paint the background, ground and cast shadow with Munsell neutrals.

bacground

Step 2: Core shadow and reflected light

I just block these in, without any blending.

shadow

Step 3: Half tone, centre light and highlight

Again, these are just blocked in, without any blending or fancy business. I usually paint the half tones and light more thickly and with more texture. It helps create the illusion of form.

blocked-in

Step 4: Blending and adjusting

I spend quite a bit of time at this stage, observing and adjusting. Although the process up to this point might seem formulaic, you still need to paint when you get to this part. The more developed your observational and painting skills, the better the final result.

finished

Here’s a direct comparison of the actual sphere and my study, pretty much from the viewpoint I painted it from.

comparison

How this works in the real world

The good thing about this is that the understanding you gain from this kind of practice can be translated directly to real world objects.

People often struggle with yellows, especially in the shadows. So I used exactly this procedure to paint a study of a lemon.

Now, lemons are very high chroma, so they’re more difficult. But with an approach like this, you can find out exactly what colours you need, just the same.

lemon-palette

Here’s the palette, with the tube colours I used to mix all of those colours – cadmium yellow, cadmium orange and burnt umber.

A few things worth mentioning about this:

  • The core shadow moved slightly around the hue wheel, as with the blue sphere. It got slightly warmer, which is why there are two Munsell chips there – it was between the two.
  • All the other chips are the same hue
  • I used two colours for the half tones, to help with the modelling
  • For the centre light, the challenge was to keep the chroma high enough. I used cadmium yellow, with a small amount of cadmium orange mixed in to change the hue, but otherwise unmodified. And I painted it thickly and then made sure not to fiddle with it too much, to make sure I got the maximum chroma out of it.

Here’s the finished study, next to the lemon:

lemon-study

Modelling form with Munsell

So there’s a few very useful points you can take from this:

  • Understanding colour from a point of view of hue, value and chroma, helps you paint more realistically.
  • If the object you’re painting has a single local, then the hue will hardly change across the form. The value and chroma will change much more, so they show form turning much more than hue.
  • Understanding the ‘modeling factors’ and where they fall on a simple object like a sphere helps you clarify what you’re seeing on more complex objects, too.
  • You can use this knowledge to inform what you paint when you come to paint a real world object – like an clementine. Or a lemon, say.

Of course it takes practice to really understand colour in this way, it takes a mental shift. I’ve been working with this approach for a while, trying to understand form and colour better.

And once you understand colour in this way you can play with it. If you know how to model a form of a local blue, you can apply those modelling factors to anything – even something you don’t have physically have in front of you.

How about a blue lemon?

two-lemons

That bottom study was painted from what I’d gained from the two previous studies, without looking at the lemon at all. The colours for the modelling factors in blue come from the blue sphere. The form and the colours for the modelling factors of the yellow stripe come from the lemon study.

Although that’s a bit extreme, I hope it illustrates something: that understanding colour gives you the freedom to change things in your pictures, depending on the effect you want to create. It releases you from your visual impression, it allows you to create more – if you want to.

But most importantly – and this is where it really counts – it helps you to understand what you’re seeing and paint it much more accurately – and that means more realistically.

So if you struggle with colour and want to be able to paint more realistically, you can use this method to figure out exactly what colours you’re seeing, to mix them accurately, and then paint with them.

There will be times, of course, when what you’re trying to paint is outside the range of what paint can replicate. But even then, having this understanding of colour and light will help you to do that more effectively, too.

Knowledge really is power.

Free Webinar!

On Wednesday 24th August 2016, I gave a free webinar where I demonstrated this method of finding the right colours for the modelling factors live. It was a fun webinar (despite some sound problems towards the end!) Here’s the replay:

Best wishes and thanks for reading,

Paul

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About Paul

I'm a (mostly) self-taught artist. I paint realism in oils, mostly still life. I share my work, my evolving process and what knowledge I've gained on my own learning journey here, in the hope that it might help you along on
yours.

Comments

  1. 1

    Debra Davis says

    August 19, 2016 at 3:55 pm

    I’m so glad I found you blog. You have some wonderful posts with lots of great information.

    Reply
    • 2

      Paul says

      August 19, 2016 at 6:02 pm

      Thanks Debra, I’m really glad to hear that!

      Reply
  2. 3

    Rene says

    August 19, 2016 at 4:00 pm

    Re: the high chroma lemon painting palette
    I assume you also added white or Naples Yellow to the palette for the highlight mix. Is there anything you can add about mixing high chroma yellow or any high chroma hue? I have difficulty attaining a high chroma except by adding white, or Naples Yellow. As often said, white makes the color look chalky.
    Thanks for any advice.

    Reply
    • 4

      Paul says

      August 19, 2016 at 6:08 pm

      Hi Rene,

      No, I just used the colours on the palette (cadmium yellow, cadmium orange and burnt umber) plus titanium white.

      I think that by chalky, at least in this context, you mean loss of chroma. It’s true, white (especially titanium, which is slightly blue-ish) will drop the chroma – but the chroma actually does drop in the high light. For the centre light I used pure cadmium with only a very small amount of cadmium orange – which is also very high chroma. That was the highest chroma area of the actual lemon, so there wasn’t a problem.

      That said, I made sure to have my panel angled to the light in such a way that my pure cadmium yellow matched the centre light modelling factor on the lemon – that allowed me to match the highest chroma area quite closely, if not quite there. If I hadn’t done that, if my panel was angled more away from the light, I would have had to raise the value of the centre light with white and yes, that would have dropped the chroma and I would have struggled to match the colours.

      For this method to work, you need to make sure you have enough light on your panel/canvas to match the highest chroma and/or highest value areas of the subject – or at least, as close as you can get it.

      I hope that makes sense! It’s easier to demonstrate than to describe, so I’ll be covering that part in some detail in the webinar.

      Reply
  3. 5

    Janet L Sellers says

    August 19, 2016 at 4:49 pm

    Wow. Meticulous information. Thank you for this.

    Interesting, but it is not likely that I will use Munsell again after my 4 color separation days and the like. i like to paint plein air, alla prima, so this of course will not be handy to do. Light changes constantly as does the color perception, and I make choices based on my eyes of the moment -that is what I have, and my eyesight is stronger some days than others. Monet and I have a lot in common… So much to learn, though, for art and color.

    Reply
    • 6

      Paul says

      August 20, 2016 at 8:54 am

      Hi Janet. Yes, that’s true. But this is practice, which is something very different than performance – which is what you’re doing when you paint en plein air. Although you can’t very well do this kind of thing whilst you’re in the middle of a painting, you can do practice like this in addition – and the learning you get from it translates into everything you do.

      Reply
  4. 7

    N says

    August 19, 2016 at 5:38 pm

    Thank You Paul ! I still learn Munsell Color book and you help a lot!!

    Reply
    • 8

      Paul says

      August 20, 2016 at 8:51 am

      That’s great to hear, thanks!

      Reply
  5. 9

    Kathleen Bryce says

    August 20, 2016 at 3:19 am

    Very well designed lesson. enjoyed learning the process. You broke it down to a very simple procedure. That said I’m still challenged to get it done easily…….
    Will try doing a lemon tomorrow ! Thank you !

    Reply
    • 10

      Paul says

      August 20, 2016 at 8:51 am

      Thanks Janet. Drop me an email if you have any questions about it – do you have my email address?

      Reply
  6. 11

    Bruno says

    August 20, 2016 at 3:56 am

    You are such a great source of joy.

    Reply
    • 12

      Paul says

      August 20, 2016 at 8:50 am

      Thanks Bruno 🙂

      Reply
  7. 13

    HelenMT says

    August 21, 2016 at 5:05 pm

    Paul, I’ve been out of contact for a while, am just now catching up! Just when I think You can’t be a better teacher, You Surprise me with more! Just wanted you to know I just found out I have brain damage from chemo is why I got so confused with my painting!Seems the part I use for painting is gone! I’m starting over at beginning with your teachings to learn again! I still have the desire to paint and will again thanks to You!

    Reply
    • 14

      Paul says

      September 10, 2016 at 6:13 am

      Thank you Helen! I’m very sorry to hear that the chemo has affected you so badly. Very sorry. If there’s anything I can do to help, get in touch.

      Reply
  8. 15

    Chris de Wet says

    August 22, 2016 at 10:16 am

    Excellent lesson Paul!

    Reply
    • 16

      Paul says

      August 22, 2016 at 6:26 pm

      Thanks Chris

      Reply
  9. 17

    James says

    August 22, 2016 at 1:07 pm

    Hi Paul,

    Thanks for the great article. I assume the hue doesn’t change much because the objects were lit by sunlight and sitting in a neutral grey shadow box. If the colour of the light or the environment changed, it would affect the hue of the objects, correct?

    Reply
    • 18

      Paul says

      August 22, 2016 at 2:12 pm

      Exactly right, James. Although the objects here were lit by indirect, diffused daylight, not direct sunlight.

      If I’d lined the shadow box with high chroma red paper, the hues of the shadow areas would be significantly different.

      If I’d used an artificial light of a strong colour, say yellow, the colour of the light areas would have been significantly different.

      For this exercise, the point is to light as neutrally as possible, so that you can learn the most about colour and light without being thrown off by anomalies.

      Reply
  10. 19

    ML Meek says

    August 22, 2016 at 5:04 pm

    You are generously sharing information that I personally have found to be extremely helpful. Just want you to know how much you are appreciated.

    Reply
    • 20

      Paul says

      August 22, 2016 at 6:26 pm

      Thank you! That’s great to hear 🙂

      Reply
  11. 21

    Lisa Rickard says

    August 25, 2016 at 1:53 pm

    Thank you, Paul for an awesome presentation and well thought out example of how understanding color leads to painting better realism as well as having more creative choices. I’m an atelier student beginning to paint in color. (I don’t have a website yet, but 3 of my atelier projects are included on the atelier’s student drawing page.) I have been working with the MUNSELL student book (on my own – unfortunately not part of the atelier training). I am interested in purchasing the Big Glossy Munsell Book of Color, but found this less expensive alternative:

    http://www.munsellcolourscienceforpainters.com/AnAffordableMunsellBook/AnAffordableMunsellBook.html

    Or would you still recommend the Big Glossy book as an upgrade from my student set?

    Reply
    • 22

      Paul says

      September 10, 2016 at 6:12 am

      Thanks Lisa.

      I haven’t seen that book before, so can’t vouch for the accuracy of the chips. However, I do have the big book so I’ll get a copy of it and check the chips against it.

      Part of the reason the big book is so expensive is that they do extensive testing of each copy to make sure the chips are accurate.

      Your drawings are really wonderful, Lisa! If you add the colour knowledge that Munsell can give you to your wonderful drawing skills, you will have an enviable skill set!

      Reply
  12. 23

    David M says

    September 11, 2016 at 5:19 pm

    Hi Paul!

    I just wanted to tell you how much I love and appreciate your wonderful posts and lessons.
    Thank you Master, you are a great teacher (and I deeply believe you’re also a great person)!

    Wish you the best,
    David (aspiring painter)

    Reply
    • 24

      Paul says

      September 12, 2016 at 9:44 am

      Thank you David, that means so much to me!

      Reply
  13. 25

    Robert says

    September 14, 2016 at 11:43 pm

    A friend turned me on to your blog. Thank you. Add me to your email list and blog also. Thanks again it was very insightful.

    Bob

    Reply
    • 26

      Paul says

      September 15, 2016 at 7:16 am

      Thanks Bob, I’m really glad to hear you like the blog. I’ve added you to the email list.

      Reply
  14. 27

    Alva says

    September 19, 2016 at 1:11 pm

    Oh thank you. So good.

    Reply
  15. 28

    Noreen Joyce says

    October 16, 2016 at 12:52 pm

    Paul, I think you did a fantastic job teaching that lesson,…

    A really good method… I’m goin to look for more of your blogs , .. I’m hoping there’s one on colour theory … Which I am concentrating on at the moment ….. and I head is addled with it ,!

    Reply
    • 29

      Paul says

      October 17, 2016 at 11:00 am

      Thanks Joyce! I tend to take a very practical approach to colour, so I’m afraid you won’t find much on colour theory here – this post is about as close as it gets!

      Reply
  16. 30

    Janet Silverstein says

    December 14, 2020 at 3:12 am

    Just came across your webinar. After not picking up my brush for 2 years I signed up for a 4 week course which was given by a very good, well known on social media painter who, as it turns out was a useless instructor! I learned more in your free one hour webinar on color than I did in the month of the other course which was a waste of time and money. Silver lining was that I got back to my easel and started to browse the net to discover your blog. So thank you. Not sure I can invest in another course right away and the Munsil book. But I would like to know more about your offerings and the course. What I missed most was constructive feedback and some technical direction which I used to get back in art school.
    Look forward to your reply.
    -j

    Reply
    • 31

      Paul says

      December 16, 2020 at 1:19 pm

      I’m really glad to hear you got back painting Janet, that in itself is a great step.

      Yes, painting and teaching are very different skill sets, and not all artists see the need to develop them both, I think. When I hear stories like yours I’m always put in mind of Frannk Brangwyn, an incredible painter who was apparently an awful teacher!

      Thank you very much for the kind words. If you want to keep up to date with what I’m offering, the best thing to do is to subscribe to the email list:

      http://www.learning-to-see.co.uk/subscribe

      Reply

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Hi, I’m Paul

I'm a (mostly) self-taught artist. I paint realism in oils, mostly still life. I share my work, my evolving process and what knowledge I've gained on my own learning journey here, in the hope that it might help you on yours.
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