Guidelines for Presenters

These are some considerations when preparing and presenting a program at the SFBC member’s meeting. Be sure to ask if you have problems or questions.


Your presentation should be about 35-45 minutes. The subject should be somewhat cave-related. A good rule of thumb is 80 to 120 slides for your talk. Fewer slides are a good idea, too, as having more slides will require you to display slides really fast. There are often a few questions during and after your talk.

Short movie clips are popular if they can be shown relatively seamlessly with your pictures.

For digital photos, there are a variety of different slide show programs available. These include iPhoto, PowerPoint, Picasa albums, Faststone and Keynote. The program should include the capability of exporting both the slides and slide organization and control to a DVD or USB memory stick as a back up. Owing to federal network security issues, there is no USGS-provided Internet access in the meeting room.

The grotto owns a Kodak Carousel 35mm slide projector and an overhead transparency projector. Ask well in advance if you need these. They are stored at the Frantz ‘s estate.


Load your presentation onto a Laptop (Windows or Mac) that you will bring to the talk.

Bring an adapter cable if needed to connect to the USGS ‘s Mini DB15 male VGA plug.

Make sure that the adapter is appropriate to your computer. Apple has changed their adapters over the years. Some adapters look the same but only work on a specific computer model. Most Windows laptops do not require an adapter cable as they come with a Mini DB15 female socket that mates directly with the USGS Mini DB15 Male.

Back up your show on a USB drive or a DVD.

It is often not enough to just back up your slides. The presentation software you use includes control and ordering information that also needs to be backed up. There will be other Windows and Mac laptops in the audience that can be borrowed in case your computer fails. But your entire presentation would need to be move to the borrowed computer and not just your pictures. Don’t ask us how we know this!

Bring amplified external speakers if your presentation has audio.

Bring a laser pointer if you wish; we are not video streaming our Grotto programs, so there is no requirement to use the on-board cursor / pointer to highlight points of interest in your images.


SFBC meetings start promptly at 7:30PM except when they don’t. Try to show up early (20 minutes) to verify that your pictures appear properly on the screen. Ask for someone to help you set up if you have not done a show in this room before.

Pull the projector screen down manually using the pole with a hook; this device is stored near the front of the room.

Start projector with the remote control that should be inside or on the podium. Press the pink ON/OFF button on the remote to power the projector. The projector takes a few minutes to power up. Don’t panic (yet).

Most laptops have a mode that allows you to view your slides on the computer’s monitor in addition to sending the signal out of the laptop’s external video port. Most laptops require a key sequence to enable this mode. Make sure you know how to cause your computer’s video display to be output via it external video port.

Project a few slides on the screen and verify that the aspect ratio is correct (slides are not squished in one direction) and that the colors and contrast of the projected slides are approximately what you see on the screen. If there are aspect, contrast, or color issues, adjustments are possible on the projector and/or on your computer. The projected image will never be exactly the same as on your laptop’s monitor. It may be possible to tweak the projected image; see Optimizing the Projection below for hints.

If your computer is not functioning properly, copy your presentation onto another requisitioned computer’s hard drive. Running the show directly from a DVD or USB memory drive may be too slow, as USB port speed takes awhile, especially if you have loaded multi megabyte images.


Generally speaking, the best viewing experience will be obtained by setting your laptop’s video output and the projector input to the highest resolution that will display your images with the correct aspect ratio. An incorrect aspect ratio will cause your photos to look squished or stretched. Circles will appear as ovals.


Resolution is the number of vertical and horizontal bits of information being displayed. Aspect ratio is the relation of the picture’s width to the picture’s height. Resolution and aspect ratio are not necessarily directly related as your display software can use non-square pixels.

Many laptops utilize display integrated circuits that can output a higher resolution image out of the external video monitor port than on the laptop display itself. You can set up the projected image to a higher resolution / better quality than your monitor. Laptops may also be able to output a variety of aspect ratios.

The USGS projector is a Sanyo Multiverse PLC XP50. The projector is capable of the following resolutions and aspect ratio:
     Native = 1024 x 768 pixels; Maximum = 1280 x 1024 pixels; Aspect Ratio = 4:3

This projector is no longer in production; be kind to it.


There is a wide variety in the way colors are represented on laptops. Images can appear way too dark or way too light on the projected screen but show perfectly well on the laptop’s monitor. Colors can be off or spectrally shifted as well. Apple uses a non-linear display matrix which may make colors more vibrant on Apple displays but can make your slides un-viewable if the projector is not set up to handle the Apple color palette. Windows computers with their linear matrixes often require little color adjustment in the projector. Unless you are matching colors professionally, the default settings are likely to work just fine.

The projector be need to be calibrated with your particular laptop output. Apple (in the display “preferences”) provides a sequence of test images and instructions that allow you to adjust the projector’s brightness and contrast and then color space to your specific laptop output. The projector’s brightness, contrast, and color representation can be adjusted using the remote control, although typically will not be necessary.

While less of an issue with each passing year and software and hardware upgrade, there are enough versions of PowerPoint and other presentation software packages out there that going from a Macintosh to a Windows box can present problems if the fonts used in the presentation are not cross-platform compatible. The easiest work-around: To minimize problems with how written information appears when projected, plan to use the same computer to project the show that you used to compile the show.