The Scanner
By Mark Mayhew
I promised to return this month with an in depth look at digital hardware. So I will begin by getting to grips with a scanner. There are three types of scanner basically, film, flatbed and hand held. A film scanner is just what it says and scans negatives and trannies. A flatbed scanner will scan photographs and anything really that is flat. Finally there is a hand held scanner. Of the three the most common and generally the most useful is the flatbed scanner.
They all work in exactly the same way though. A light is passed over the picture and using mirrors and a lens the light is reflected down onto a CCD chip. This chip then converts the picture details into a digital representation. Simple. If Only!
First basic concept you need to understand is dpi. Dots per inch. As the light passes across your print the sensors pick out tiny (pixel) sized details to convert. Obviously the more pixels the sensors record the better the detail in the finished scan. Normally flatbeds and hand held scanners work within 300 to 600 dpi. This is very acceptable when say scanning a 8x6 print to then print at much the same size. A problem will arise when large magnification is required. Suppose you scan a small print of 4x3 and want to print it out at 8x10. You can see logically that when the original scan was produced at say 300 dpi when you want to print out at this magnification you will be short of a lot of pixels. So the individual pixel size will be increased by the software giving you a blocky picture. (Details of magnification and dpi are in last months article. Ed)
So if you plan to mainly scan film or tranny then you will need to invest in a film scanner. If you have loads of small prints and want to scan to make very large prints then you will need to invest in a good quality machine that has high dpi scanning. If mainly you intend to scan and print at much the same then 300 to 600 dpi will be quite satisfactory. As with anything to do with computers always get the best you can afford, but there is no need to go mad and break the bank.
No matter where in the world you live there will be a great many magazines that compare scanners against each other. All you need to decide is what your requirements are and then find the best for you. All scanners come with software and will be TWAIN compatible. Every one is different, but from my experience all seem to do much the same thing. If you are serious about image manipulation though you will find the bundled software lacking for what you need. Just use it for scanning in and then use whatever program you are happy with.
If you have been thinking about getting a scanner, but wondered if you would really get any benefit from it, please do. The wonderful experience of playing around with your own pictures is brilliant and as much fun as a darkroom with none of the mess that goes with it. It's a lot cheaper as well, because it doesn't matter how many mistakes you make your not wasting paper and chemicals.