Number 234 - October 2002

Getting Desired Results From Your Printer
From Bruce Preston column in Danbury PCUG's dacs.doc
Q. Could you talk about what affects image quality when you print a photo image?     A. Starting with the basics--for good photos you need good paper. Think of regular paper (such as used in copiers, laser printers, etc.) as being much like a paper towel. Think of the drop of ink being placed on the paper as writing with a felt-tip pen. The ink will `wick' into the paper and disperse, blending with adjacent colors. To prevent this, photo-quality paper has a very thin coating of clay which prevents the ink from wicking. Next, consider the resolution of the printer and the image. A typical photo quality printer can support 1,400 dots per inch. If you are printing across the width of the paper, you have 8x10 paper; at 1,400 resolution, then your image would have (8"x1400 ) by (10" x 1400) or about 11,200 by 14,000 pixels in it. If you are working with 32-bit color, that would be about 4MB in size. If your camera doesn't supply that much information, then the printer driver is going to have to interpolate (or	estimate) what color the missing pixels should be. So, if you are looking for quality, you have to have the data to support it. The next thing that affects quality is the quality of the printer driver--does it estimate so as to get better speed? and things like that...     (Need I say it? You have to start with a good picture - TOGGLE ed)     Q. Is that why the same file when printed on the same printer looks better when printed from my Mac than from my PC?     A. Given the same data, they should come out the same. So it is either the photo-imaging software being different, the printer driver being different, or the settings in the printer control panel being different. On a PC, be sure to go to FILE, then PRINT so that you can examine the settings. Usually, just clicking the print button in an application goes to the default settings.
Number 234 - October 2002