Here at Print Colchester we offer a range of services, including the most comprehensive range of scanning in Colchester. Our services are tailored to our customer requirements, whether you need large format scans at up to A0 sizes, or just a simple A4 document scanned. We cater for scanning architects plans, large multi-page documents and high quality photographs. Selecting the correct format for scanning can be difficult – so let us help out with a quick guide to choosing what kind of scanning you need.
Sometimes you just need to get your scanning job done, and a low quality scan may be fine for this. For example when sending a shopping list to a friend pixel perfect results may not be paramount. However when working with print documents you need to get the best quality results possible to keep your photos and images looking super sharp. One thing to remember though – the more pages you need scanned and the higher the quality, the bigger the files. Large files can be cumbersome to store, email and process – so make sure you pick the right scan for the job.
Black & White Scanning
The quality of scanning relies on a few different things. The most obvious is whether the scan is in colour or black and white. Black and white scanning is often thought of as the lowest quality and produces files that are small in size – sometimes as low as a few 100kb. Most scanners have a black and white setting that reads your documents and analyses each dot as either black or white. This is sometimes known as bitmap or binary image scanning, or 1 bit scanning. It is suitable for low quality output where small file size is important. It can be used with large multi-page documents to produce files suitable for OCR (optical character recognition) – turning your scanned documents into computer readable text files.
Next along the quality chain is greyscale scanning. This format is still black and white, but this time the individual dots are analysed and returned as shades of grey. This format can be used for higher quality document scanning, giving nice smooth results for text. It is also more suitable for black and white photograph scanning, where a good range of tone can be reproduced. File sizes are larger with this format, but not huge as the file only has to hold data for 1 ‘channel’.
Colour is obviously king when it comes to scanning. With colour scanning three separate colour channels are read by the scanner – red green and blue. The documents produced are known as RGB files. The three channels of information are combined into one file creating large files. In the world of office scanning this might be suitable for scanning in old Powerpoint presentations or reports. Photographs however are the more obvious target here. If you are looking to archive your old snaps then colour scanning is obviously the way to go.
That Tricky DPI Again
We’ve spoken at length already about that tricky dpi, but to pin it down for scanning lets keep it simple. Higher dpi values mean higher quality files, with larger file sizes. 200 dpi scans should be fine for Facebook snaps, but if you are looking to print a brochure 400 or 600 dpi scans would be a great starting point.
Keeping File Sizes Manageable
Compression is also a governing factor when it comes to scanning. The most popular compressed file format is Jpeg. This format in essence takes your image and replaces the individual dots in your large blocks of colour (like perhaps the sky) and replaces them with a general description for that area. Jpeg compression works on a sliding scale. This means that a high compression factor will apply this technique enthusiastically, creating small file sizes with lots of the data replaced. Low compression factors will be less keen – larger files not replacing as much data and keeping the image more true to the original.
Hopefully that gives you some idea of the factors influencing what kind of scanning to choose – but if you’re still not sure why not drop us a comment? We’ll be happy to answer any queries you’ve got. Or you can drop us a mail by using our contact page. If you’re looking to get some documents scanned yourself you can pop into our store in Colchester town, or snail mail your documents over to us. Include a stamped self addressed envelopes we’ll get them straight back to you.