Scientific Poster Graphics

A Picture is Worth a Thousand Words

It has been proven that visual aids (charts, graphs, diagrams, images, etc.) increase the effectiveness of your poster. Be sure to use the right visual aids to have the right effect! An attractive poster may catch a reader's eye at first glance and draw them in to read your poster or listen to your presentation. An illustration of a complex process or technical mechanism may aid in better understanding the information. Just communicating a concept visually will help you to communicate the message faster, and will help the reader retain the information.

Image File Formats

The types of graphics that can be imported into your PowerPoint fall into two main categories; Bitmap (Paint-Type) and Object-Oriented (Draw-Type). We recommend using common formats such as .JPG, .BMP, .WMF or .TIF files. Unusual files such as QuickTime compressed, Picture Viewer, PICT & EPS don’t always translate well. When you are saving or exporting your images, you need to carefully determine the file type in order to get the best looking final image.

Bitmap Graphics

Bitmap graphics are commonly created by basic painting packages, such as Microsoft Paint. Most scanning packages also utilize bitmap formats. Bitmaps are comprised from a series of small square dots (pixels). Depending on the format of the particular bitmap, each of these dots can be black, white, some particular color, or a shade of gray.

Limitations of bitmap graphics:

• Because bitmaps are made up of dots, sizing the graphic may distort it. Sizing the graphic proportionally minimizes the distortion.
• Bitmap graphics can be very large. Scanned bitmaps at 300 dpi (dots per inch) can easily exceed 1 megabyte (MB). This causes slow screen redraws and creates larger Publisher files. Printing problems may also occur with large images.
• Bitmaps do not typically output at as high a resolution as an equivalent object-oriented graphic format.

Object-Oriented Graphics

Object-oriented graphics, on the other hand, are not comprised of a series of dots. They are a set of instructions that tell the computer to draw lines, boxes, polygons, and so on. Such a file is basically an equation for generating the image, rather than the actual pixel by pixel representation.

Object-oriented graphics have several advantages over bitmaps.

• A graphic can usually be resized without distorting the image. Object-oriented graphics are generated by a formula; therefore, if you resize the image, the application recalculates the formula to compensate for the change in size.
• Object-oriented graphic files are much smaller in size.
• They output at the highest resolution supported by the output device. In other words, if you send an object-oriented graphic to a 1024 x 1024 resolution printer, the graphic would recalculate and output at that resolution. A bitmap, on the other hand, is always limited by the initial resolution at which it was created. In most cases, this is no better than the screen resolution, 75 DPI for VGA, unless the image was scanned.

Typical programs using object-oriented graphics are CorelDRAW!, Micrografx Designer, Microsoft PowerPoint, Microsoft Excel, Adobe Illustrator and many others.

Information courtesy of Microsoft.com

Scanning Pictures

When scanning pictures that will be included in your poster, we recommend saving them in .JPG format. PowerPoint can import most JPG files easily. If you are not sure about the printing quality of your scanned image, as a general guide, zoom in on the picture until it fills your entire screen and look at it. Doing this should give you a general idea of how well the picture will print when it's enlarged. If it looks pixilated and jaggy you may need to re-scan it at a higher resolution. We don't recommend using graphics that have been saved from the web.

On the flip side, if you use a resolution that is too high you may end up creating a graphic (and therefore PowerPoint file) with an unnecessarily large file size that becomes hard to transmit and open. There is a cap on the resolution where the quality of the graphic will look the same, but the file size will continue to increase as the resolution is increased.

Cutting and Pasting Graphics

There are several different methods of cut and paste because objects act differently depending on what method is used. If you will need to edit the item in its native application (by double clicking, if available) after it is pasted in PowerPoint, use the Ctrl+V keystroke to paste the item in place. Otherwise, we recommend using the Paste Special feature so you have more control over how your graphics look.

Here's How:

Go to Edit > Paste Special and use the explanations below to choose the best option from the pop-up box. This is a general guide that may vary between the different versions of PowerPoint.

• Items pasted as an enhanced metafile cannot be edited in their native application. They can only be ungrouped to dumb objects in PowerPoint. Ungrouping will cause charts, graphs or vector objects to split up into 100s of pieces.
• Items pasted as a picture cannot be edited. Depending on the type of object, the result will be the same as a pasted enhanced metafile or it will turn into a jpg (bitmapped picture).

Resolution

Never, ever incorporate "web" graphics without extreme caution. Most web images have 72 dots per inch (dpi) of resolution, but printing at that resolution looks absolutely terrible, and the figure will be a huge turn-off to prospective viewers. Graphics should have a resolution of 300dpi or more when printed. Try not to enlarge a 300dpi graphic once it is brought into PowerPoint, as it will then decrease the resolution resulting in a lower quality image. If you need pictures, try gaining access to a high quality digital camera. Take plenty of pictures from different angles and with varying lighting to ensure that at least one has crisp detail, good composition, non-distracting background, etc.

Borders & Lines

If you include a photograph, add a gray or black border at least 2 points thick to make it more visually appealing. Choose a line color that is subtly pleasing but barely noticeable to the viewer. Avoid using lines with a thickness less than 2 points as they won't show up on your poster because they are so thin!