Image Processing

Cameras, Software, Scanners and Printers

Here is the presentation made to the Pastfinders Computer Users' Group on February 19, 2003 at 1:30 PM in the Genealogy Room of the Cooper Memorial Library. Comments follow.

Comment Summary: The following is a summary of comments made during the presentation following somewhat the order of the slides.

Cameras: Be aware of what cameras can do so that you can get one that meets your needs. Be sure you understand its capabilities and where to look for help in performing certain actions (if all else fails, read the manual). Cameras generally have several modes of operation: program (point and shoot), aperture preferred (set the aperture and let the shutter speed be automatic), shutter preferred (set the shutter speed and let the camera set the aperture) and manual (you do it all). Exposure control allows you to let the camera do its thing but somewhat darker or somewhat brighter based on how you set it. Needed to darken sunsets and brighten beach scenes. Optical zoom magnifies an image to make it apear closer. Digital zoom does in the camera what you can do in the computer but it a simulation and not a true magnification. Use zoom to make distance objects appear near; use its opposite, wide angle to squeeze everyone into a group photo. Macro allows photos in the range of 1 to 2 feet and super macro allows you to get is close as 2 inches. Need to photograph anything for EBay?

Cameras generally can take pictures in several resolutions. The table below lists some popular ones. The image size capable of being printed at 300 dots per inch (dpi) is also listed. While this standard is often suggested, violate it as long as you are satisfied with the result.

Camera resolutions available today are

640 x 480 = 307,200. At 300 dpi that’s 2.1 x 1.6 inches. 350,000 pixels

800 x 600 = 480, 000. At 300 dpi that’s 2.67 x 2.0 inches,

1024 x 768 = 786,432. At 300 dpi that’s 3.4 x 2.56 inches, 810,000 pixels

1152 x 864 = 1,003,968. At 300 dpi that’s 3.84 x 2.88 inches. 1 Megapixel

1280 x 1024 = 1,310,720. At 300 dpi that’s 4.27 x 3.4 inches.

1600 x 1200 = 1,920,000. At 300 dpi that’s 5.33 x 4.0 inches. 2 Megapixels

2048 x 1536 = 3,145,728. At 300 dpi that’s 6.8 x 5.12 inches. 3 Megapixels

2272 x 1704 = 3,871,488. At 300 dpi that’s 7.57 x 5.68 inches. 4 Megapixels

and up.

If you plan on working with the image in software where you will open it, work on it and save it perhaps multiple times, I would suggest converting the image to TIF format if it isn't already (its probably a JPG image). Each time its opened and saved it gets re-compressed and loses something. It's a good idea to save the original and only work on a copy. That way you won't have to go back to Africa and re-take that picture of the charging tiger that you destroyed trying to get the color right.

Uploading Images: Plan ahead to create a folder to move your images into (although some programs will ask if you want a new folder). You can use the software that came with your camera or generic software such as the free Ulead Photo Explorer. Move the images into the folder that you want renaming them at the same time if your software permits. Or you can use the rename command in windows to batch rename them. Select the files to be renamed by using clicking on a file and SHIFT-clicking on the last file in the group. Right click on the first file in the selected group, click on RENAME and provide a name and then press enter. The rest of the files in the group will be renamed to the same name with a sequential number.. If the files are not consecutive, use CTL-click on each file to be selected.

Card readers are available that will read the memory card from your camera. Most are USB readers and they can read up to 6 different card types. Get one that at least handles the card used by your camera. They run around $30. They are treated by Windows as a new hard drive and you can drag and drop files from the card reader into any folder on your hard drive. You can copy them or move them. I prefer to copy them just in case something happens. When you're sure that they all got there you can erase the memory card. Note that the memory card and reader can be used as a portable disk drive to move anything you want from one USB capable computer to another.

Scanners: We covered the basics of scanning but there's little to be said here other than to refer you to the page on scanners already listed under Articles on our home page. It can be reached here.

Image Software: You probably received some image software with your camera or scanner. They all do about the same thing but some are more capable than others. The standard is the $699 Adobe Photoshop and it also comes in the stripped down form of Photoshop Elements for $99 or the Photoshop LE that comes with camers and scanners. We took a picture taken at our Christmas Dinner where because of the flash, the people in the forground were illuminated but those in the back were extremely dark. We used Photoshop LE and went to IMAGE, ADJUST and EQUALIZE. The background was immediately brightened. Most programs have such a command even if it has a different name such as STRETCH DETAIL or AUTO BALANCE. It's the place to start when trying to bring detail out of the shadows. Because the foreground became a bit too bright we applied a dark to light GRADIENT FILL from front to back that did reduce the foreground highlights but also reduced the contrast. We then went back to IMAGE, ADJUST and CONTRAST/BRIGHTNESS and increased the contrast. Given the time we would have tried something and if we didn't like it we'd click on EDIT, UNDO. Professionals would have created a new layer and applied all the corrections to that and succeeding layers creating a new layer for each effect but there was nowhere near the time to do more than suggest that reading the tutorial and trying things out is a good way to get familiar. We used the RUBBER STAMP tool to copy from one area to another to wipe out the reflection from the flash on the window behinf the head table. Sometimes called the CLONE tool it copies whatever you move the index pointer over to a new area. It's great for removing power lines from photos and even removing people or swapping heads.

Internet Printers: When you have your pictures safely into your computer you'll want hard copies. You can print them yourself or you can send them off into space and let someone else do it. I showed photos that had been printed by Shutterfly. Those places listed above are perhaps the most popular but there are hundreds of places to go. They will send to proprietary software that you can use to select images to send to them, select the ones you want printed, the sizes that you want and where you want them sent. You can tell your friends and relatives to look at the pictures on the site and they can order if you authorize it. Generally they provide some means of photo correction and they offer special ways to use photos such as on cups and tee shirts.

Printers: It's assumed that we're talking inkjet printers here. Inkjet photo printers are available that use 6 inks instead of 3 plus black. They offer somewhat better tonal gradations. Some printers come with inks in separate tanks so you don't have to throw away ink when one cell runs dry. Ink also comes in pigment instead of dye form for longer lasting prints. But you can refill them with a refill kit.

Most printers provide a menu where you match the resolution to the type of paper automatically. The printer asks for the type of paper you're using, whether you want the fastest or the best printout and you don't have to worry about resolution. But your input image should be on the order of 300 dots per inch. The printer resolution doesn't have to match and should be higher. You probably can't do any better than 300 dpi so there's no sense wasting disk space for images at higher resolutions. You may find that 100 dpi images satisfy you. Listed above are various types of paper and material that you can print on. Course materials such as canvas and tee shirts need minimum resolution images around 100 dpi or so. Don't forget to print the tee shirt transfers backwards. If your printer software won't do it, you can flip an image in any image software program.

Bonus Coverage: Here are some items that should have been mentioned but weren't.

EFIF: This is a standard file that is attached to a digital photo. It provides the time and date of the photograph, aperture, shutter speed, exposure compensation, flash etc. It can be found by opening My Computer and navigating to a folder containing photos. Right click on any photo in the listing or on the thumbnail and click PROPERTIES and then click on SUMMARY and then on ADVANCED. This works in Windows ME and XP and probably other versions. None of the image programs that I tried provided that information.

Printer ink: Printer ink dries out fast. Most cartridges have a date code so try not to buy too much at one time. If your printer has an ON/OFF switch, always use that to turn off your printer-don't use a power strip. The printer has to park it's heads to keep the ink from drying out and it can't if you shut off its power. When your print has gaps use the CLEAN PRINT HEAD procedure that came with your printer. Use NOZZLE CHECK to see if all of the nozzles are printing-there should be no gaps. Try cleaning again-- some say up to three times. Ink softening kits are available for very stubborn cases.

References: Information, prices and test results on cameras and computer equipment:

Free image software:

www.ulead.com Photo Explorer www.irfanview.com IrfanView Graphic Viewer