One of the common complaints about graphics used in presentations or on web sites is the poor quality. Even if you scan in an image at high resolution, it seems that most graphics end up looking awful. It is usually because the size or resolution has not been properly adjusted. I recently helped someone with a photo they put on a web site that took up most of the page and took forever to load because it was 2MB.
The size of the graphic is the easier of the two areas to understand because we can just look at the image and see what size it is. If you take a large picture and simply use the sizing handles to make it smaller, the image appears the correct size, but the problem is that the graphic file is still the same size, making the presentation file huge or the web page slow to load. The quality of the image is also variable depending on how well the program displays a large image that has been resized.
The second issue is with resolution. This refers to the number of dots per inch in the picture. The higher the resolution, the better the quality of the image. Where that rule falls apart though, is where the device you are viewing the image on cannot display more than a certain resolution. And your computer monitor is a device that has a limitation. In general, computer screens display no more than 72 dpi (dots per inch). For print publications, it is not uncommon to see resolutions of 1200 dpi - even laser printers print at 300-600 dpi. When you scan an image for print use, you must scan it at the high resolution. But when you go to use it in an electronic format, you should resample it down to a lower resolution. Resampling is a process where the software intelligently removes dots from the image but does not reduce the overall quality of appearance.
To resize and resample an image requires software. You can use expensive, complex image software, or you can do what I do, which is go cheap and easy. I use a great utility called IrFanView (interesting name, great software). This utility allows you to load an image in any of dozens of formats, resize, resample and do a whole lot of other things if you need to, and then save in any of lots of formats. I have used it extensively to help my images appear crisp and clear on my web site and in presentations. I highly recommend it and encourage you to start using it to improve the quality of the images you use in presentations and online. Here is a link to download IrFanView from its home site:http://www.irfanview.com. Some people also resize images using the Microsoft Office Picture Manager which is one of the tools included as part of Microsoft Office.
If you include the image in a PowerPoint presentation that will be shown using a data projector, remember to check how the picture looks through the data projector. Depending on the room lighting and the brightness of the bulb, I have found many images appear much darker when displayed through a data projector than what they look like on the computer screen. You may need to adjust the brightness of the image to make it look good when displayed. To do this in PowerPoint, use the Brightness setting on the Picture Tools Format tab. Increase the Brightness setting to by 10-15% above the default. You don't want to increase it too much or it will start to wash out the details shown in the image.
The steps I usually follow when using a scanned image are:
- Scan the image at a high resolution so I can use it in a print publication if required.
- Resize and resample the image for use on a web site or in a presentation.
- Adjust the brightness of the image in PowerPoint.
By taking care to get the best quality images in our presentations and web pages, we increase the impact of our message, which leads to more enthusiastic action from our audiences.