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Lighting 103: Using Gels to Shift the Ambient

Lighting 103: Using Gels to Shift the Ambient

Abstract: By combining a white balance shift in your camera with a complimentary gelling of your flash, you can easily and efficiently alter the ambient color temperature of an entire environment.

In addition to controlling the color of light from your flash, gels can also allow you to control the color of the ambient areas of your frame. This can allow you to tweak, enhance or drastically an ambient color environment.

The portrait above, done for the Baltimore Sun, is a good example. I shot him as a storm approached, and the light was gray and pretty neutral.

It was okay, but I wanted a stronger color environment for the photo, and I wanted the guy to pop more. So instead of daylight white balance, I shot it on incandescent (tungsten) white balance. This shifted the expected light source from 5600k to 3200k. In essence, the camera was expecting to shoot under tungsten lights.

But since the ambient environment was closer to neutral (a little cooler, even) the white balance setting had the effect of shifting everything way more blue.

I lit the subject with a single speedlight with a cardboard snoot. The snoot would help me to control the spill of the light form the flash.

To balance my flash’s light to my camera’s white balance setting, I had to turn it into a tungsten source by adding a full CTO gel. But I did not want my subject to be neutral, I wanted him to be warm and pop out against the blue. So I added another 1/2 CTO to the flash to overcompensate the color and render him in warm light even with the white balance shift.

This warm-on-cool effect makes him stand out, even though he is pretty small in the frame. In addition to being blue-shifted, the ambient is also underexposed between two and three stops. That helps the fully lit (and warm) guy stand out, too.

For comparison, here is a straight (no color shift or gel) lit version:

It’s okay, but it doesn’t have the color environment that the shifted version does. It’s a subjective choice, to be sure. But it helps my guy, bathed in warm light, to pop out from the scene.
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Most of the time when we color-shift the ambient using white balance and gels, we do so along the warm-to-cool scale. And it does not have to be a full-on, change to tungsten white balance shift, either. You can use your Kelvin white balance scale to tweak the warmth or coolness of your ambient light as much or as little as you want.

Then you simply counterract that shift with the appropriate complimentary amount of CTO or CTB gel on your key light. And since gels come in calibrated full and partial CTO/CTB units, this is very easy. In essence, with this white balance and gel combo, you can choose your ambient color at will.

It’s Like In-Camera Photoshop

But there is no reason to limit yourself to warm vs. cool. You can use a white balance shift and complimentary gel to shift the ambient in any direction you want.

Take the portrait of contortioninst Shelley Guy, above. She is lit against a post sunset sky. I can leave it like that or I could shift the dusk light in any direction I wanted.

Shifting the white balance toward magenta, for instance�”and compensating with a complimentary green gel on my flash�”I would get this:

In the end, I stuck with the straight sunset. But the point is that we have the ability to shift the ambient in any direction we want, assuming we can gel our flash in the complimentary direction.

Like the Room? Fine. If Not, Change it.

So remember in the last post where we talked about looking at the scene on daylight white balance and seeing what color the room is giving you? If you don’t like it, you can change it in any direction you want. Just remember to gel your flash in the complimentary direction if you want to zero out that color shift in our white balance.

With our color-graph indicators in the cameras’ white balance controls, and a Rosco CalColor® gel kit, this becomes easy. Just gel your flash in the opposite direction as your white balance shift to compensate.

In the end, the CalColors® are not really so much about coloring your flash as they are about controlling the color of the ambient environment. Use your WB to shift the ambient, then the (complimentary) calibrated gels to bring your flash back as needed.
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This technique can save you a lot of flash power, too. For instance, say you are building a night scene and using a lot of blue-gelled lights to establish that feel. Each of those blue gels is gonna cost you a stop or two of flash power, depending on how deeply colored they are. And since you may be lighting large areas with those flashes, they need to be backed up and power will be at a premium.

Instead, flash with white light and shift it all with your camera’s white balance. Then use gels to counter-shift the key light(s) to compensate. These lights will tend to be closer to the subject, and can handle the power loss more easily.
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A couple of things to remember:

• If you are not getting the saturation you want or expect from a white balance color shift, try underexposing the ambient. As with the photo at top, color shifts become more pronounced when coupled with underexposure.

• To make the subject stand out from the color-shifted background, try overcompensating with complimentary gels on the key light. For example, if shooting in a tungsten white balance setting, try using a full CTO + 1/4 CTO, or full CTO plus 1/2 CTO. That will make your subject warm against the cool, rather than just neutral.

• Or you may wish to integrate the subject into a color-shifted environment, as in the previous post. In this case, try compensating with a complimentary gel�”but not all the way. In the scenario above, you might choose just a 1/2 or 3/4 CTO on your key light.

ADDITIONAL READING:

In 50 Portraits, Heisler often uses strong, saturated color in his light sources. But he also will tweak the ambient environment in just the way we are talking about above. Since Greg has done the majority of his work in film, he tweaked the overall scene the analog way�”with a physical filter on his lens. He could then compensate with his gelled flashes in the same way described above.

To understand the amount of ambient shift that is being applied, it helps to know the strength of the filters being used. In the double-truck photo of Dale Earnhardt, Jr., on page, 126, that deep blue dusk look was courtesy a Wratten 80A deep blue filter on the lens. A Wratten 80A is the equivalent of a full, daylight-to-tungsten blue shift.

In the double-truck photo of George David, on page 178, a Wratten 80D filter was used. The 80D is a lesser cooling shift than the 80A, as one might do today by tweaking the Kelvin white balance scale on your digital camera.

Either way, the effect was to enhance the color of the ambient environment before applying any flash.

COMING NEXT: Gel Your Lamps

This is the most recent post in Strobist’s Lighting 103 module. New installments publish on the first and third Thursday of each month. If you would like to be notified as they become available, please sign up here.


How to Shoot and Stitch a Panorama Photo

How to Shoot and Stitch a Panorama Photo

Sometimes the landscape is just too big. Sometimes, just one image won’t do the trick. Then it’s time to create a panorama!

How to Create a Panorama photo

I’m fortunate to spend a lot of time in the grand landscapes of Alaska. But often, camera in hand, I’ve stood there, unable to create the image I wanted. There was just too much going on, or things were happening in a way that just didn’t match a typical single-image format. I was photographing along a gravel beach near Haines, Alaska this winter, while the alpenglow was lighting up the peaks across the inlet. The glaciers and spires were painted in peach light. Going super wide to capture it all, with my 14mm, made the mountains too small and distant, and left too much empty space. I wanted the details in the

I was photographing along a gravel beach near Haines, Alaska this winter, while the alpenglow was lighting up the peaks across the inlet (see image above). The glaciers and spires were painted in peach light. Going super wide to capture it all, with my 14mm, made the mountains too small and distant, and left too much empty space. I wanted the details in the mountains while maintaining a sense of the vast landscape. A panorama was the only way to go.

How to Create a Panorama Photo

Panoramas are hardly a novelty, Smartphones and many point and shoots can create them in-camera. But stitching together images from a DSLR or other high-resolution camera will yield better results if you do it right. Sadly, panoramas are easy to screw up. Here are a few tips for making an effective panorama from a series of images.

What lens to use to make a panorama

Making a panorama isn’t the time to use a wide angle lens. The optical distortion inherent in these lenses tends to mess with the process of stitching them together. Pick a standard lens or a short telephoto; something between 40mm and 100mm will work well, though I’ve occasionally gone as high as 200mm if the situation warrants.

How to Create a Panorama

Remove all filters from your lens, especially polarizers. They can cause gradations across an image that are impossible to work with later, so get that thing off your camera.

Cameras and settings

I shoot all panorama images in RAW format. This allows me greater flexibility in post-processing to make sure that exposures, white balance, and other settings match from one image to the next. That said if you are careful in-camera, and manually select all your settings from ISO to exposure and white balance, you can get by with JPGs.

How to Create a Panorama Photo

Exposure

Take a few sample shots of your subject. If you are shooting a landscape that varies in tones, meter off the brightest part of your scene and make the image as bright as possible without blowing out the highlights. Take note of those numbers (exposure settings), then using Manual Mode set your aperture and shutter speed accordingly.

How to Create a Panorama Photo

Focus

Turn off autofocus. As you pan across your scene, you don’t want your camera grabbing a new focus point each time. Set the focus so that your subject is sharp, then don’t touch it again until you’ve finished the series.

How to Create a Panorama Photo

White Balance

There are two options for white balance. The first, and easiest, is to set your white balance in camera, using one of the presets. Don’t use auto white balance, because the camera may decide each image varies slightly, and the colors will shift within the final panorama. Pick something appropriate and stick with it. The second option is to set the white balance of your RAW images in post-processing (see below).

How to Create a Panorama Photo

Making the images for the panorama

Composition

Almost all of my panoramas are created using vertically formatted photos (i.e. the camera is oriented vertically). First, this allows me to stitch together a greater number of photos for the same scene. Second, it allows me to compose with more negative at the top and bottom. This dead space is important to allow for cropping later.

Here is a series and final image to show you how I took the shots:

Notice how there is overlap from one image to the next, and they are all shot vertically. So nine images were stitched to make this final panorama image.

Shooting

How to Create a Panorama Photo

A level tripod is very useful, but not absolutely essential. If you are using a tripod, level it. With a level tripod, as you pan, your camera’s angle will not shift up and down. If you are hand-holding be very careful to keep your camera level as you move across your scene shooting your images for the panorama.

Start a full frame to the side of where you expect your final image to begin. This assures that you have some negative on the sides of the image. Then begin making your series as you pan right or left. Overlap each shot by between a third to one-half of the frame each time. The overlap is what allows the computer to detect which images go where and line them up, so make sure to leave plenty of overlap.

Move across the scene making as many images as necessary to fully capture the landscape. Take a breath.

How to Create a Panorama Photo

Post-processing your panorama

Continuity

In the computer (I use Lightroom), go through each your series and confirm that the white balance of each image is identical. If you shot in RAW, assuring white balance continuity is as easy as checking that they each have the same color tone. Check the numbers, if they aren’t all exactly the same, change them so that they match. If you set your white balance in camera, you can skip this step.

How to Create a Panorama Photo

Don’t edit the images separately, leave your photos as they are out of the camera (except to make sure the white balance is the same). Any additional post-processing is best done once the panorama has been created.

Stitching

There are many programs that can create panoramas. These include specialty programs like PTGui, which is designed to create enormous images involving hundreds of individual photos. However, both Photoshop and Lightroom have merge to panorama capabilities which work great in most situations. As an example, I’ll go through the steps in Lightroom:

Select your images by clicking the first one in your series, pressing and holding the Shift key, then selecting the final image. All the ones in between will now be selected as well.

Right-click (PC) or Control-Click (Mac) and select Photomerge > Panorama.

How to Create a Panorama Photo
A preview window will pop up offering three options; Spherical, Cylindrical, and Perspective. For most simple panoramas, Cylindrical will work, but feel free to click back and forth between these options to find the best option for your image. Click Merge.

How to Create a Panorama Photo

The stitched image will appear in your Lightroom Library, or as a new image in Photoshop. The result will likely have some jagged edges from your base images not quite lining up. Select the crop tool and cut the jagged edges away. (This is why the negative space I noted earlier is so important.) Note: you can also check off “Auto Crop” in the panorama popup box and it will be done automatically for you. 

Once you’ve got your image cropped you can post-process as you would any other photo in your collection.

How to Create a Panorama Photo

Conclusion

Panoramic photos, while definitely not the best option in all scenarios are a great tool to keep in mind for those moments when a landscape is just too big, too dramatic, or too epic to be captured in a single photo. When I first started shooting panoramas many years ago, I regularly overlooked simple things like remembering to remove my polarizer, or failing to assure the same white balance from image to image. Screw up a setting or forget a filter and the final image just won’t work, and there is nothing you can do about it. Pay attention to those annoying little details and you won’t miss your chance to create some epic panorama images.

Do you shoot panoramas? If so, show them off below, or share some of your own tips for success.


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