When I started my first tentative floral scans (yikes! 11 years ago now!) I really had no idea about dpi, resolution, file formats or any of the technical aspect of scanner photography. Yes, I have a computer background and so bits and bytes and similar technology was familiar to me, but best practices with regards to scanning and manipulating the resulting images was new to me and I could easily have lost many early works to bad practices or trial and error.
Fortunately I was given a copy of Wayne Fulton’s “A Few Scanning Tips” – a printed copy, though this information is found on his http://www.scantips.com site. This book grounded me in several key areas that saved me lots of regrets and hard lessons.
A prime example: Wayne’s book hit home that JPG files have what is called a “lossy” compression, meaning that some information in the image is lost every time such an image is edited, all for the sake of reducing file size. A beautiful flower scan will lose quality when it is touched and saved, even at the higher quality levels. The answer? Use TIF format, and the LZW compression algorithm. While the file sizes will be substantially larger, you can edit them repeatedly without any quality loss from reducing the file size. Since most of my work has large border areas that are pure black, the algorithm works well (instead of storing information for each black data point it says “use black for the next n points”). Since my scans typically take 8-15 hours to edit, being able to save repeatedly over the several evenings the editing will take is very important.
His work also drives home points about differences is displaying pictures on monitors, which use pixels, versus printed output which is in dots per inch, and both systems use different color schemes – RGB or sRGB for monitors, CYMK color profiles for printing.
My original printed copy of “A Few Scanning Tips” was from 2001 and so already a bit behind the technology when i received it in 2006 but much of the foundational reference information is still sound, and his web site has more current information. So if you’re looking for the “why’s” of image formats, scaling, resolution and more, it’s a worthwhile resource to have in your browser favorites!