The cost of digital imaging has dropped significantly over the last few years. It has become affordable for every home PC user to own a scanner. Scanning is an area of home computing that is full of terminology and may put some people off. This is not a step by step guide, there are too many different types and versions of software packaged with scanners out there, but we hope to give new users of scanning technology a bit of confidence and hopefully give the more experienced a few helpful tips.

The most common acronym you will see when using a scanner is dpi. This means dots per inch, Monitors and printers build a picture or page using dots of colour but there is a huge difference between viewing an image on a screen and printing the same image onto paper. Typically images that are viewed on screen are created using 72 dots per inch and most printers print using 300 dots per inch or more. Therefore images viewed on a screen would appear larger than if the same image were printed. For other terminology see the glossary [0] at the end of the page.

Older scanners will only be able to scan opaque items or printed matter, newer models come equipped with add-ons, that will scan slides and negatives too. We have the capability of scanning any photographic image, if you would like your photographs and or slides digitised send them to us using our freepost address, all the information can be found here [0].

Setting up the scanner

Most scanners will have their own software to make it easy for you to capture documents and photographs ready to be backed up and or reprinted. When scanning in a standard sized photograph (6” X 4”) the digital picture will have 2,160,000 colour pixels making up the image (at 300dpi). The short side will be 1200 pixels in length, compare this to the average settings for a windows desktop of 1024 x 768 pixels and you can see that the standard size photograph will be more than one and a half times bigger than the screen.

When displaying an image onscreen you should scan the picture at no more than 100 dpi, even then you may need to crop or resize the image to keep within our site restrictions of 400 pixels wide x 400 pixels high.
Most scanners sold today are capable of scanning both transparent media (slides etc…) and reflective media (photographs, documents, books etc…), and most software used to capture the digital image will have an option to choose between reflective and transparent.

There is one other option that you will need to check, and that is how you would like the image scanned (sometimes called “scan mode”) most scanners offer three options, Colour RGB, Grayscale and Line art (or Black & White).

The digital image

Some scanners produce a nicely cropped image with no black edges, however if you find that your picture needs a little cropping or editing, then irfanview [1] is an excellent free piece of software.
Once you have the image in your preferred piece of software you can optimise the image quality. Imaging software typically includes an option to adjust the colour balance or “levels”.

Once you have finished editing you will need to save it, the recommended file type for saving photographic images for use on the web is “jpg” or “jpeg”. You will need to choose how much compression or what quality you would like. The higher the quality image the larger the file size will be. Most photographic images used on this website have been saved using 40% compression or medium quality.

Common Problems

Image out of focus

If your image is out of focus, there is probably something between the glass bed and your photograph. If that is not the issue, make sure that your glass bed is clean and clear, if someone has cleaned the bed check that the glass has been replaced correctly.

Cannot read the text

If you are having difficulty reading a scanned document. Try scanning the document again at a higher resolution, we recommend scanning documents at 150 dpi minimum.

Glossary

dpi

Dots Per Inch, the number of dots of colour per linear inch, most printers print at 300+ dpi and most monitors display between 72 -100 dpi depending on your screen size and screen resolution.

jpg or jpeg

Joint Photographic Experts Group. It is a form of file compression specifically designed for displaying photographs on the Internet.

gif

Graphics Interchange Format. It is an image file format that can only contain up to 256 different colours.

compression

Is a process that reduces the number of bytes required to define a document in order to save disk space or download times. It can be achieved by replacing common sequences of pixels with shorter codes.

colour balance

Is the term for the dynamic range of the colours in an image, it can be manipulated by replacing colours at the top and bottom ends of the range with similar colours closer to the center of the range to create clearer sharper images.

crop

Taking away the edges of an image to remove an unwanted portion.

pixel

a dot on a screen / monitor. The smallest part of a digital image.

scanning bed

It is the piece of glass that you place your photographs onto.

resolution

Is the number of pixels in an image or on a monitor screen. The higher the number of pixels the higher the resolution.

If you have any terminology that you think should be added please create a comment using the add new comment link.