Why You Can’t Paint a Black Shadow (But How to Make it Look Like You Did)

Have you ever tried to paint a shadow cast on a black surface?

Because you can’t do it. Well, you can, but you can’t match it accurately in paint.

“Nonsense”, I hear you cry, “It’s simply a case of using black paint! Ivory black will do it!”

Ah, not so, I’m afraid. Read this post to find out why.

Values Matter

I’ve recently returned to painting some little value studies. They might not make the most beautiful of paintings, but they do make very interesting subjects.

Why? Because I’ve learned more about value from painting simple little studies of cubes and spheres than I have from all the finished paintings I’ve ever done. Seriously.

Why do I say this? Well, here’s what good understanding of value gives you:

• Understanding of how light works. Without light we have nothing to paint. In fact, we don’t really paint stuff, we paint light reflected off stuff (I think I first heard that from William Whittaker, a man who can paint). If you’re a realist painter, light is your subject whether you like it or not. So understanding it better will make you a better painter.
• Feeling of Form and depth of space. Once you can create a feeling of light, believable form and the illusion of depth come for free.
• Stronger compositions. Value is incredibly important in creating compositions. The better you are at handling it, the stronger your compositions will become.
• Light effects. When you’ve gained enough understanding, and practised enough, you can manipulate the values in a picture to create the effect you want. Rembrandt and Turner approached value in very different ways, creating very different effects.
• You can make something look real. I know I’ve already said this. But I’m saying it again because I want to underline it. If you want to paint stuff that looks real, you need to understand value. You need to be able to play it like a classical violinist plays her instrument.

So what’s the best way to master value? Easy: Studies. By taking out all other considerations – colour, composition, technique, making a beautiful picture to impress your friends with, pretty much anything else – and focusing only on value, you can fast-track the rate at which you learn.

You still have to put in the hours, of course. But once you’ve done those hours, you’ll find that when you come back to trying to make a beautiful picture, or to paint something that looks real, your new knowledge will allow you to get much, much closer to your goal.

Why you can’t paint a black shadow

OK, so let’s get back to this black shadow, and why you can’t paint it.

Actually, it would probably more accurate to say, “why you can’t match it”.

Because you can paint it, but not by painting what you see.

We’ve all heard the line “that’s not art, that’s just copying what you see.” Well, that’s nonsense. I’m about to give you one example of why, if you want to paint something that looks real, you need to paint something other than what you see. You need to translate your visual impression into something that works on canvas; into something that creates an illusion.

Let me show you what I mean by example.

For the little value study I’m talking about today, I put a mid-grey cube (Munsell value 6, if you’re up on Munsell notation – slightly lighter than mid-value grey if not) in a black shadow box made from foam-core. The shadow box is useful because it controls the light. There’s very little reflected light bouncing around, and we can concentrate purely on the light falling on the subject.

In order to help with that focus, I often use a little viewfinder taped to the back of the board I’m painting on. The viewfinder has two big benefits:

1. It focuses my attention on the subject
2. It makes it easier for me to judge the values I see.

Here’s a picture of the little study I painted, next to the subject as I saw it, through the little viewfinder.

What I want you to notice about that is that the darker values on the study are not as dark as the corresponding values on the subject.

Why is this? I used ivory black for my darkest dark, and that’s as dark as paint gets.

The darks in my study are lighter because it’s painted on a flat surface and there is light falling on it. So some of that light is being reflected, making my black appear lighter to me, it actually looks like a dark grey.

In comparison, the darkest area of the subject (the cast shadow behind the cube) appears darker, because it’s a complete absence of light. There’s no reflected light coming into the cast shadow. It’s an absence of light.

So I can’t match it with black paint. My cast shadow will never appear as dark as the cast shadow in the subject. I physically can’t paint what I see.

That’s one reason why values are so hard to get right. The value range of paint is significantly more narrow than the range we see. That’s true even with indoor light like this. Unless you confine yourself to painting mid-value objects with mid value backgrounds, you can’t match the values you see.

What I did instead

In the first study (the top one in the picture above) I painted the top of the cube and the side facing the light the actual values I could see. I matched them exactly. I also matched the ground in front of the cube. Since I can’t go as dark as the darkest darks on the subject, the range in my darks on my study is compressed.

As you can see from the first photo in this post, the cast shadow doesn’t really stand out from the background in the first study – nowhere near as much as it does on the subject. That’s what happens when you try to paint what you see – you run out of room in your value range.

So for the second study, I allowed a larger range of values for the darks. The ground in front of the cube is a little lighter. The background overall is slightly lighter. The values of the front and top of the cube are a little lighter (but not much).

Painting the edges

Where the edges of different values meet, I’ve pushed the values a little to make them appear more different overall than they really are. That means that the value blocks in the study are less uniform. For example, the front face of the cube is lighter where the edge meets the shadow side.

I’ve also stressed the edges of some parts more, and blurred them elsewhere. Edge handling is a big subject and outside the scope of this post for now, but let me know in the comments if you’d like me to write in a little more detail about that.

The main difference between the first study and second one is that in the first one, I’ve tried to paint what I saw. In the second one, I accepted that I couldn’t paint exactly what I saw, and looked for ways to change the study so that the cube looked more real, even though that meant departing from a literal representation of the cube.

Here’s the second study along with the subject. In many ways it’s more different from the subject than the first study is. The light planes of the cube are pretty close to the subject. But the dark areas overall are lighter. It’s less accurate. But it’s a little more convincing as an illusion of form I think.

Conclusion

It took me a long time to realise this: Painting something so that it looks real isn’t the same thing as matching what you see, except in a very few cases when you have a narrow value range in your subject.

So value isn’t about absolute accuracy. It’s about the relationships between the values. It’s about being able to manipulate those relationships in order to create an effect you want. If you want to create the illusion of reality, most of the time you’ll need to depart from what you see. Because most of the time, you don’t really have any choice.

Useful things about value you can learn from studies like this:

• The value of a cast shadow is dependent on the local value of the surface it is cast on. If a shadow is cast on a black surface, it will be black. If it’s cast on a light surface, it will be much lighter.
• You can’t paint an absence of light. So you can’t reach all the values you see, even in indoor light, in most conditions.
• Painting value isn’t so much about replicating what you see accurately. It’s about preserving relationships, and it’s about the effect you want to create.
• Taking elements of painting and drawing out like this and practising them separately helps you make more progress more quickly.

Expect more of these little studies and the thoughts that go along with them over the coming months. I’ve got my cubes and my brushes out again, and I meant to use them – to learn (and hopefully share) even more about value.

I’m planning a few more of these studies over the coming months, and they’ll get more complicated and challenging as time goes on. For example, if I had a white surface in this study, I wouldn’t have been able to push the values of the top and from faces of the cube up without compressing lights – the same problem I had with the shadows, but at a different end of the scale. When you’re trying to paint a broad range of values, it gets really complicated really quickly.

For the next study, I’ll post a more detailed description of how you can make a shadow box and set up and paint little studies like this for yourself.

Please follow along. Try your own versions. If you’re serious about improving your handling of values, it’s the most useful thing could do.

Thanks for reading and best wishes,

Paul