Power of the Photograph
I love still images because the photograph captures a moment in time, allowing the viewer to slow down and think and wonder and reflect. Many filmmakers—especially documentary filmmakers—use still photos as a complement to motion pictures or video. Photos allow for greater emphasis and may have less distracting elements, giving the presenter or narrator/filmmaker more freedom to augment the photo for a desired effect. Still images also allow the viewer time to interpret their own meaning from the image. We can learn a lot from documentary film, especially from the kind created by Ken Burns, whose films rely heavily on still images.
One tip is to avoid the usage of imagery only as ornamentation. What you see in a Ken Burns film is a simple and powerful use of photos and other imagery that support the narrative and illuminate the story on a visceral level, thereby making the experience richer and more memorable. When we hear a story that is amplified by compelling photography, the issue in the story becomes less of an abstraction. The issue becomes more concrete and emotional. The next time you give a presentation about an important but complex topic—especially a social issue—see if you can illuminate the general topic by focusing on a particular story. This is a technique that storytellers, such as filmmakers, often use. Powerful images plus thoughtful narration—and maybe even a bit of text—can help you tell your story in ways that bullet points never can.
The use of large images in these slides make an especially powerful impact. (Images in slides from iStockphoto.com.)
Full-bleed images offer ultimate impact
Margins around an image give it a sort of protective frame. When you compare two or more images on slides, margins are necessary to clearly differentiate among the images. Generally, however, people use images that are too small, making it hard for audiences to see the content, thereby reducing the impact of the photo.
When it makes sense to do so, I suggest you bleed images off the edge of the slide frame. That is, fill the entire slide area with the image. (Bleed is actually a term that comes from the printing world. In a book like this one, when you want to fill an entire page with an image, you must use an image that is just a tiny bit larger than the area of the page. In other words, you bleed the image off the page to make sure none of the underlying paper color shows through the trimmed page, which would destroy the effect.) With slides, all you need is an image that is exactly the same size as the slide. If your slides are 1024 x 768 pixels, for example, then the dimensions of the image need to be at least this large to fill the screen. A full-bleed or full-screen image gives the illusion that the slide is bigger than it is. This is especially true if part of the subject in your image runs off the screen. For example, a burger shop may make a poster featuring a picture of their “Enormo Burger,” but with part of the burger bleeding off the edge to suggest that it’s so big it can’t fit within the frame. This makes the image more compelling and it draws the viewer in.
With a full-bleed (or full-screen) image, the background slide is gone. Now the image becomes the background and the type becomes part of the image, creating a more dynamic, engaging visual that is easily seen from the back of the room.
Now the image takes up the entire screen for a more dynamic effect. The type is easy to see in both cases, but a black box is added to the version on the right for even better legibility.
This is an example of taking a busy slide and breaking it up over several slides (in this case, four slides). The slide on the left repeats many of the things the presenter will share with the audience before he describes the efficient rail system that moves an incredible amount of people all around the city each day. But instead of using loads of text on a slide, he uses large dynamic visuals in harmony with the flow of his narrative. There are now four slides. First he explains what is meant by “Greater Tokyo.” Then he takes the audience onto the train platform to give them a feel for the crowds. The slide than fades to a blurry version of the same photo so that the text—his key point— can be seen easily. The last side appears as he emphasizes just how large a number 40 million is by comparing it to the population of New Zealand.
(Images in slides from iStockphoto.com.)
The slides in the left column are the originals. Note how the message in each slide has greater impact when the image fills the slide (right column).
The ideal resolution for projection
As a general rule, use images that are 72 ppi to 100 ppi with dimensions that are the same or very close to the slide dimensions. For example, 800 x 600 or 1024 x 768 when you want to use an image that fills your entire slide (a slide with an aspect ratio of 4:3). For slides with a more cinematic aspect ratio of 16:9—an aspect ratio increasingly common at large events such as TED or professional conferences—photos may need to be at least 1280 x 720, a popular resolution for a 16:9 screen.
Flickr offers millions of searchable images with a Creative Commons license. When you find an image you like, right-click (Control-click) the image to see all the sizes available for that image. In the example on the left (one of my snaps from Sydney), the largest size in this case is 1200 x 768. My slide dimensions are 1024 x 768, so this image will work fine. Once in slideware (below left) you can see that the image is a bit wider than the slide, but I can simply move the image to the left to get the framing I want. Simple.
Improve images through cropping
Cropping is a technique for reframing or adjusting the composition of an original photograph. Of course, it’s always better to take the perfect shot or purchase the perfect image, but that does not always happen. Cropping changes the image to better suit your needs. For example, you may have images of interesting subjects, but the composition is not what you had hoped. I have loads of holiday snapshots that are not that great, but can be improved with a bit of cropping.
I took this shot of Bondi Beach in Australia a few years ago using a simple digital point-and-shoot camera. The original resolution was 300 ppi, measuring 2816 x 2112 pixels. The size of the file was 4.2 MB. For images that will be placed in slideware, a resolution of 72 ppi or 96 ppi is usually fine. So I first reduced the resolution to 72 ppi, which decreased the file size to 1.9 MB. Next, I decreased the dimensions of the slide to something closer to 1024 x 768, the size of my slides, using basic photo-editing software. Because I started with such a large image, however, I can go inside the photograph and frame it in a way that is a little more interesting and specific. Using the cropping tool, I selected an area of the photograph that shows only the surfer, leaving plenty of empty space in case I want to place text inside the image. Now, the image measures just a bit over 1024 x 768 and the JPEG file size is about 300 KB. I could reduce the file size further through more compression, but this would decrease the quality of the image.
The large image is the original snap I took at the beach. The image below is the cropped version of the image, which is now the same size as the slide on the right (1024 x 768 at 72 ppi).
Basic image file types
Of the many different image file formats, you really only need to be familiar with a few:
- JPEG. The most common image file format you will work with is JPEG (.jpg). JPEG stands for Joint Photographic Experts Group, but you do not need to remember that part. Just remember that JPEGs (jay-pegs) use “lossy” compression, which means that a bit of image quality is lost during compression. Usually, the loss in picture quality is only noticeable when you are using a high level of compression. JPEG is the preferred format for photographs used on Web pages. Small JPEGs may look great on a Web site, but they usually look horrible if you significantly increase the image size for a slide. When you’re selecting large images for slides, make sure the size and resolution of the original image will work. JPEG compression does a good job with photographs, especially when you have lots of colors blending into each other, soft shadows, and so on.
PNG. PNG, which stands for Portable Network Graphics, features lossless compression. While I most often use JPEGs for onscreen presentations in slideware, I do occasionally use the PNG (.png) format to achieve a transparency effect, such as those shown below.
The images in these slides are PNG files. I created the gradient transparency effect in Photoshop. The PNG and TIFF formats support these kinds of transparency effects. (Images in slides from iStockphoto.com.)
- TIFF. If you need to print images, I recommend the TIFF format (.tif), which stands for Tagged Image File Format. Use TIFF files for printing images in CMYK. (TIFF files can include an alpha channel for transparency effects and can work in slideware, but the TIFF files are much larger than PNG files.) TIFF files can be compressed without losing picture quality; however, compared to JPEGs, TIFF files can be much larger. Larger file sizes will not usually create problems, especially with newer computers, but there is no reason to create unnecessarily large files. On older computers, larger image files can slow things down a bit.
- GIF. GIF, which stands for Graphics Interchange Format, is a file format used mainly for the Web. The GIF format may be appropriate for line art with very sharp edges and large areas of the same color. GIF reduces the colors in an image down to 256, so it is not good for photographs.
EPS. EPS stands for Encapsulated PostScript. You may run into the EPS format when you purchase line art or vector graphics or create your own line drawings in an application such as Adobe Illustrator. An EPS file can hold photographic information as well, but you are most likely to see this format used for vector graphics. The advantage of vector graphics is that you can greatly increase the image scale without decreasing the image quality. To illustrate this, I took a vector graphic from iStockphoto and converted a copy of it to a small bitmap (JPEG) image. When I scale up the bitmap image, you see the quality is reduced as the pixels get larger. The vector image, however, looks great scaled because it uses mathematical formulas to make sure all the points on the paths maintain their original relationships. The EPS format is good for drawings, but for photographs you’ll stick primarily with good-quality JPEG files.
In this slide, the image on the left is a small JPEG that I stretched, resulting in some horrible pixelation. The vector version of the image on the right stays crisp at any size.