Last time, we considered the method of showing a proper shadow cast from a light source which is behind the viewer. This lesson today will demonstrate the opposite situation, where the light source is before the viewer.
Andrew Loomis in his book Successful Drawing shows us the method of solving how to draw shadows in proper perspective. The first point which needs stating is a concept hinted at from 2 postings past, which I hope to make concrete by the end of this lesson. The aforementioned idea is that if the light source is Behind, the angle of light is below the horizon. When the light source is before the viewer, the angle of the light is above the horizon. Hold onto this thought, and I will review it at the end of the lesson, where I am sure it will form an integration for you.
Here are the steps for casting a perspectival shadow from a light source which is before.
- Set up your horizon and the object using proper perspective. Establish the Vanishing Points for the object’s sides, and draw the appropriate angles. Draw the guidelines for the perspective on a separate layer of vellum or digitally, then remove the guidelines when the object is perspective. Save the layer.
- Since the light source in this exercise is before the viewer, it is proper to next establish the position of where that light is coming from specifically. This should be done with precision within the layout phase of your drawing. Even if the light is not going to be within the boundaries of your finish crop for the illustration, you must lay it out with exact placement, or else your shadows will appear unconvincing. Drop a line vertically down at 90 degrees from the centre of the light source to the horizon line.
- The point where the vertical line crosses the horizon will be the VP of the shadows. This is a crucial step, so pay close attention to it. As a rule, the Vanishing Point of shadows is directly below the light source when the light is cast from a Before placement. The blue lines below represent the projection for the Shadow VP. Please not that these guidelines cross through the corners of the object you are drawing, laying on the ground plane.
- Next we will cast the lines of light, which will fall like a triangle from the light source. Each corner of the object you are drawing will interrupt the light, but the perspective you have chosen may conceal certain corners. In this drawing there are 3 corners which will cast a shadow we can see, so there will be 3 lines. If your object and perspective yields more corners which will cast a shadow, use the appropriate amount of lines. Note how the light lines emanate from the centre of the light source, not its perimeter. Cast the light lines further than where the Shadow VP lines lay on the plane.
- Now, turn on the layer with the original perspective lines showing. These perspective lines will give us the other half of the information we ned regarding where the shadow’s perimeter will lay.
- Where the red light lines cross either the blue Shadow VP lines or the black object perspective lines with demarcate the corners of the cast shadow your object will make, given the perspective you have chosen, and the placement of the light source. I have numbered these 1-4. Numbers 5 and 6 are the points where your object touches the plane it rests on, and from these points the shadow will originate.
- Outline the cast shadow perimeter, then fill it in with the value appropriate for the light intensity you are describing. The darker the shadow, the brighter the light. Add half-tones to the shaded sides of the object (the sides facing away from the light) Flat planes have even shading, curving planes will appear as a gradation.
- Remove the guidelines to reveal your illustration of a properly done shadow, in perspective, with the light source before the viewer. Congratulations!
As a last comment, think back the the idea of the angle of light above and below the horizon which I mentioned at the beginning. If you think about it, it is natural to recognize that the angle will come from above when the light is before, because when standing on the earth, you perceive the horizon above you. If the light is coming from behind, the angle must come from below for the same reason. It is possible, tho rare that one’s point of view can be distorted, such that the horizon is perceived as below you. This could occur if you are inverted or suspended in the air. Such points of view will break this rule. Luckily, there are limited calls for illustrations of that type. I will cover such considerations at a much later date, due to their peculiarity.
There are many more subtleties related to cast shadows, but I believe I will go onto showing organic cast shadows in perspective next week. It will be a difficult one!
The method of placing a shadow into perspective is an important skill to have as an illustrator. There is a method which Andrew Loomis shows us in his book called Successful Drawing. I will outline it here, following a short preamble.
When we look at an object on a plane, we see it in perspective, as it appears from our point of view-or our perspective. The angles recede to a point on the horizon called the Vanishing Point, which always changes depending on where the viewer is situated.
The shadows cast by an object sitting on a plane will also have a vanishing point, but it is relative to the direction the light is being cast, as well as to the viewer’s point of view. Working out the perspective the shadow takes, relative to the viewer is a factor of drawing the primary object into proper perspective- if you have done this, the P.O.V perspective of the object’s shadow will follow suit. This is only the first consideration though, as stated above, the shadow also has to fall relative to the direction the light is being cast.
I will demonstrate Loomis’ method of solving this problem.
- First, as will all drawing, one should set out the horizon line, and decide on the vanishing point, or points if the perspective is 2 point or more. Here is a sample with 2 Vanishing Points, labeled V.P. below.
- Once the VPs are set up, draw lines going to them, as per the shape you are drawing. It is important to draw a geometric shape at this stage, then convert it to an organic shape later once the perspective is worked out, since it is easier to solve these issues geometrically. Here I intend to draw a box shape.
- Here is the box shape drawn in using the two VPs.
- Now, once you have decided on the object’s perspective, it is time to decide on the next major piece of information which an illustrator needs, in order to create a convincing picture; the direction of light. You should be aware that this stage is not regarding the angle the light is falling from, just whether it is coming from the left of the object or the right. The angle is determined later. For this image, I chose the light to be coming from behind-right. (NB. Last posting defined the direction terms Behind and Before as being relative to the viewer, not the subject matter. If the light is behind the viewer, the direction line comes from below.)
- Light travels in a straight line, so this direction line you set is very important; it will now show us where the VP of the shadow will be, relative to the light. As stated before, the shadow’s perspective relative to you will be taken care of on account of the shape you have drawn already. Whichever perspective that shape is in will define the POV perspective the shadow takes, as we will use the corners of the shape as reference points for the shadow. When you cast the line the light is travelling at, the point where it crosses the horizon will be the VP of the shadow. Bisect the horizon with a vertical line where the Shadow VP lays.
- Once the vertical line bisecting the Shadow VP has been established, we can now determine the angle of the light. The vertical drawn will act as our gauge to keep the angle constant. Choose the most prominent corner of your subject matter, and at an angle of your choosing, cast a line which goes through the prominent corner, as well as through the vertical line you drew in step 5. This will be the primary angle of the light.
- Since there are more than 1 corner which catch the falling light, we need to determine where that far, and hidden corner of the box would be. This is done by again casting lines to the 2 original VPs we chose for the box. Cast your lines to determine the back side of the box using the corners which you can see on the right and left. I used the blue lines to demonstrate this below.
- Once that is done, describe the back side of the box, using dotted lines, and make a note of where the corners are.
- The second upper corner of the box, hidden by the side which faces you is also within the purview of the light which is falling. You need to now account for the angle of the shadow it casts, using the first Angle of Light you decided upon. At the crossing point of the Angle of Light and the vertical line which bisects the Shadow VP, draw up again, crossing through the new, hidden corner you just solved in step 8. This will tell you how the shadow falls relative to that corner, and the angle of light. This new angle line I have drawn below, it is the thinner of the two lines describing the Angle of Light.
- Now, using the heretofore unmentioned bottom corners, cast lines from both the near and far corners, going to the Shadow VP. These lines will give us the side edges of the cast shadow, and they are represented in dotted blue below. The red Angle of Light lines show us where the shadow will end, in a straight line between the two crossing points of the 2 dotted blues, with the two reds.
- Please note, I marked an X where the far corner of the shadow would appear (at the crossing point of dotted blue and the thin red Angle of light line). You can see that the X is within the body of the subject matter, indicating that the back corner of the shadow cannot be perceived by a viewer standing at the perspective we chose for this object. This is what I was meaning by saying that by properly drawing the subject matter in perspective will take care of the shadow’s P.O.V perspective. Here is the X marked in the drawing below, with pink lines outlining the box’s shadow which such a perspective and angle of light would cast. The far corner of the shadow is behind the box. The shadow extends from the bottom of the subject matter where it touches the plane.
- Finally, remove the guidelines and fill in the shadow with a dark tone, relative to the brightness and quality of light you would like to represent. I kept the angle of light lines active, so you can see how the corners of the shadow will meet them.
Thank you for reading this week’s posting. Next week I will show you how to cast shadows in perspective from a light source which is Before the Viewer.