Compositing

Learning goal

You will be able to combine photos shot at different times or in different places into a believable scene, as if shot in a single moment, and state this honestly. You will explain that a composite isn't just cutting and pasting with a mask, and that for the parts to look believable they need to match each other in the direction, hardness and color of the light, camera height and perspective, sharpness and noise. You will learn to build this match during the shoot with light matching and camera height matching, and in editing to match tones and colors with adjustment layers; you will add the contact shadow that settles a figure onto a surface. You will tell apart technical combinations such as panoramas and focus stacking from composites that change a scene, and grasp why the latter aren't accepted in documentary, news and competition contexts or need to be stated with a composite label. You will match the skin of people shot in different light to a shared light, and get a person's permission before putting their photo into another scene.

The question

For one version of the cover, the band wants the four of them to stand in front of a concert hall with the stage lights on. There are two photos at hand: the four members in the courtyard in the late-afternoon sun, shot from eye level, and, on another day, an empty concert hall shot from the balcony looking down. With a person mask, the drummer cuts the four members out of the courtyard and pastes them onto the photo of the hall.

The result looks fine at first glance, but after a few seconds something feels strange. The sun hits the members' faces from the left, while the hall's lights come from the front and from above. The hall is seen from above while the members are seen straight on; it is as if they are floating above the floor. Their skin is in a warm evening light, the hall in a cool blue light. How do several photos combine into one scene? And when does a combined photo turn into a lie?

Context

In the masks lesson you learned to select and separate an area, and in the layers lesson to keep parts separately. These are the tools of a composite, but they aren't what make a composite believable. Believability comes from the parts looking as if they were shot in the same light, through the eye of the same camera, and at the same moment. The eye catches a small inconsistency in light direction, perspective or color at once, often even when it can't say what is wrong.

A composite also has an honesty dimension. A cover, a poster or an art photo doesn't have to hide from anyone that it has been combined; the viewer already knows they are seeing a construction. But a news or documentary photo tells the viewer "this moment happened like this." This lesson tells both how to build a believable composite and how to know what it says in which context.

Simple explanation

Why is a composite more than cutting and pasting?

A composite is combining parts of two or more photos into a single image. Cutting a part out with a mask and putting it into another photo is only the beginning of the job. For a believable composite, the parts need to match each other in several respects: the direction and hardness of the light, the color of the light, camera height and perspective, sharpness and depth of field, noise and resolution. When one of these doesn't match, the eye senses something strange.

Light matching is the light in the parts to be combined coming from the same direction, with similar hardness and similar color. As in the lesson where you got to know the four qualities of light, the direction of the light decides where shadows fall, its hardness the shadow edges, and its color the tone of skin and surfaces. A face lit by hard sun from the left doesn't sit in a hall lit by soft light from the front. Changing light direction in editing is very hard; that is why the best composites are planned before the shoot and the parts are shot from the same direction, with similar light.

Camera height matching is the parts to be combined being shot from the same height and with a similar focal length. Shooting a scene from above moves the horizon line up the frame; when a person shot from eye level is put into this scene, they look as if their feet don't touch the ground. The horizon line in the background matching the figures' eye level gives the impression that the parts are seen through the eye of the same camera. Focal length also affects perspective: putting a figure shot from a distance with a long focal length into a hall shot up close with a wide angle creates a mismatch of scale and depth.

How are the parts matched in editing?

Shooting the parts to match during the shoot is most of the job; editing makes the final adjustments. You keep each part on its own layer and, with adjustment layers clipped to it, fit its tone and color to the background. With the tone curve you match the figure's blacks and whites with the background's blacks and whites, and with color adjustments you bring the color of the figure's light closer to the scene's light. You also look at the background's sharpness and noise: a sharp figure can stand in front of a blurred background, but if the noise of the two parts is different, the figure looks pasted on; adding fine noise joins the two parts.

A contact shadow is the dark, soft shadow that forms where a figure meets the surface it stands on, right under the feet or the base of an object. In a real scene, every object blocks a little light from reaching the surface it stands on, and this small shadow ties it to the ground. A figure that has been cut out and pasted has no such shadow and looks as if it is floating in the air. Painting a shadow under the feet with a low-opacity soft brush, in keeping with the scene's light direction, settles the figure onto the ground. The edge problems you saw in the masks lesson, spill and halos in strands of hair, are even more pronounced in a composite; you need to enlarge the edges and correct them carefully.

When is a composite accepted?

Some combinations don't change a scene; they only complete what the camera couldn't capture in one go. A panorama creates a wider image by combining frames shot side by side; focus stacking gives an image sharp from end to end by combining frames focused at different distances; HDR, which combines different exposures, also widens the brightness range. These technical combinations aim to show the scene as it is and are accepted in many contexts, but many competitions still ask for them to be stated.

Composites that change a scene, on the other hand, are another category. Putting a person somewhere they weren't, replacing a sky, showing two separate moments as a single moment, shows the viewer something that didn't actually happen. On a cover, a poster, an advertisement or an art photo this is ordinary. On a newspaper page or in a documentary series, on the other hand, this kind of composite isn't accepted, because the value of these photos comes from showing what actually happened. Most competitions, too, depending on their categories, either ban composites or ask for them to be clearly stated. A composite label is a note that clearly tells the viewer an image is made of more than one photo; when sharing, even a one-line explanation lets the viewer know what they are looking at.

When combining people shot in different light into a single scene, skin is the area that needs the most care. When you put a face shot in warm evening light into a cool blue hall, you need to adjust the skin's color to the scene's light; but the goal isn't to "fit" one person's skin to another's tone, it is to show each person under the shared light while keeping their own skin color. A dark-skinned person's face can easily slip toward a gray, lifeless tone while being adapted to cool light; a light-skinned person's can turn pale. The edges of dark hair and dark skin get lost in the mask easily when placed on a dark background; you need to complete them by enlarging the edges. Finally, putting someone's photo into another scene is building a new meaning with their image; before doing this you need to get the person's permission.

Visual evidence

The drummer drops their first attempt and plans the shoot again. This time they shoot the concert hall from in front of the stage, at eye level and with the same focal length; they note that the hall's lights come from the front and slightly from above. The next day, in the studio, they shoot the four members with a large softbox coming from the front and slightly from above, to resemble the light in the hall, with the same camera height and focal length.

When they combine them, the difference shows at once: the shadows on the faces fall in the same direction as the hall's light, and the horizon line sits at the members' eye level. With a tone curve they equalize the four figures' blacks with the hall's blacks, and add a slight coolness to the figures. When the bassist's dark skin leans toward gray in this coolness, they give it back a little warmth with a person mask; the keyboardist's light skin keeps its own color. They paint a soft contact shadow under each pair of feet, and add light noise in keeping with the hall's fine noise. The four members now stand in the hall; they aren't floating. In the bottom corner of the cover they add a small note: "combined image."

Common mistakes

Summary

A composite is combining parts of more than one photo into a single image, and its believability comes not from cutting and pasting but from the parts matching in the direction, hardness and color of light, camera height, perspective, sharpness and noise. Light matching and camera height matching are best planned before the shoot; in editing, tones and colors are matched with adjustment layers, a contact shadow settles the figure onto the ground, and edges are corrected by enlarging them. Panoramas, focus stacking and HDR complete the scene; composites that change the scene aren't accepted in news and documentary work, and in other contexts they are stated with a composite label; skin is matched to the shared light while keeping each person's own color, and a person's image is put into another scene with their permission.

Mini assignment

In this assignment you will build a small composite and label it honestly; choose a person or an object and a background.

1. First shoot the background; note which direction the light comes from, how hard it is and what color it is, the camera's height and the focal length.
2. Then shoot the person or the object in a separate place, with light that fits these notes, at the same camera height and focal length.
3. Combine the two parts; match them with the tone curve and color adjustments, add a contact shadow, and correct the edges by enlarging them.
4. Build a second composite with a part deliberately shot with light from a different direction, put the two side by side and name the difference; when sharing the best result, add a composite label and get permission from the person in the photo.

Check yourself

• Looking at a composite, can you notice a mismatch in light direction, perspective or color?
• Were you able to plan the composite before the shoot and shoot the parts with the same light and the same camera height?
• Did you match the skin of people in different light to the shared light while keeping each one's own color?

Glossary

Mini quiz

1. What is the basic thing that makes a composite believable?

• A) The mask being drawn as fast as possible
• B) The parts' saturation being raised
• C) The parts matching each other in light, perspective, color and sharpness
• D) The background being blurred

2. When people shot from eye level are put into a hall shot from the balcony looking down, why do they look as if they are floating in the air?

• A) Because the camera heights and the horizon lines don't agree
• B) Because the light is too bright
• C) Because the mask is too soft
• D) Because the colors are saturated

3. What is added to settle a cut-out and pasted figure onto the ground?

• A) A rim light
• B) A lookup table
• C) Toning
• D) A contact shadow

4. When a dark-skinned person shot in warm evening light is put into a cool blue hall, their skin slips toward gray. Which is the most fitting correction?

• A) Fitting the person's skin to the other person's skin tone
• B) Giving the skin back a little warmth with a person mask and keeping it close to their own color in the shared light
• C) Turning the hall into black and white
• D) Blurring the person's edges

Answers

1. C — The eye senses small inconsistencies in light, perspective or color at once.
2. A — The horizon line and perspective of parts shot from different heights don't agree.
3. D — In a real scene every object blocks light from reaching the surface; this small shadow ties it to the ground.
4. B — The goal is to fit the shared light but keep each person's own skin color.

Summary card

• A composite isn't cutting and pasting; light, perspective, color and sharpness must match.
• Plan light matching and camera height before the shoot.
• Match tones and colors with adjustment layers, settle onto the ground with a contact shadow.
• A composite that changes the scene isn't accepted in news and documentary work; state it with a label.
• Match skin to the shared light but with its own color; use a person's image with permission.

Bridge to the next lesson

After the composite version of the cover was finished, the band's social media manager came with a new suggestion: without needing to shoot the concert hall at all, type "a lit concert hall behind them" into an editing program's AI tool and generate a background within seconds. The same program cleaned up noise with one click and erased an unwanted person. These tools sharpened even further the honesty question they had discussed with the composite. How is AI changing editing? The next lesson deals with AI-based noise reduction, removal and generation tools, and their rules in documentary work and competitions.