Scanning Resolution Explained

Choosing the right scanner is essential to ensure that it meets your specific needs. Whether you're scanning receipts, documents, photos or detailed graphics, understanding resolution is key. The Scanner Shop have provided a detailed breakdown to help you make the right choice.

Assess Your Scanning Needs

For basic tasks like scanning receipts or documents: A portable or desktop A4 document scanner will probably suffice. These compact A4 scanners are ideal for small office / home office environments, hybrid working situations. Compact, portable scanners are especially useful for sales people that travel to various locations.

Larger business organisations benefit from larger A4 scanners with faster scan speeds and network capabilities. Often A3 production scanners are required as the volume of documents needed to be scanned is high in volume. Production scanners are designed for high-speed, bulk scanning of paper documents and include larger automatic document feeders (ADF) to streamline the process. Canon, Kodak Alaris and Ricoh all provide robust A3 production scanners capable of scanning large volumes of documents at ultra fast speeds.

For graphic artists or photographers a photo scanner is more suitable due to the need for higher resolution and colour accuracy. Art scanners often have specialised features for handling images, ensuring precise and high-quality scans. Photo scanners can include A4 flatbed scanners, A3 flatbed scanners, dedicated film scanners or large format scanning solutions. We are offering FREE delivery on selected Epson scanners until 31/12/2024. For more information visit our Epson Promotions Category.

Features to Consider

Optical resolution is the actual resolution the scanner can capture. Measured in dots per inch (dpi), this refers to the level of detail in each horizontal line of the image.

• 300 dpi is generally sufficient for most users, delivering clear and legible scans for text documents.
• 600 dpi is a step up, offering better clarity for printed documents or images.
• 2400 dpi and higher is typically used by creative professionals who need ultra-high-resolution settings for scanning film producing detailed prints.

Some scanners use advanced mechanisms like precision stepper motors to enhance the resolution vertically, for instance, from 1200 dpi to 2400 dpi. This is referred to as hardware resolution. Software-enhanced resolution, where algorithms add pixels based on surrounding pixel data is known as interpolation. This process helps achieve resolutions higher than the hardware supports, but it may introduce artificial details that can degrade image quality. If high quality is essential, it is always better to scan at the highest possible resolution rather than rely on interpolation. Hardware over software. That said, high resolution scans can be enhanced in post production using the correct software.

Which Resolution to Choose?

For text documents 300 dpi is ideal for clarity and it is more than enough for web use (72dpi - 96dpi). Photos for printing - 300 dpi or 600 dpi provides good quality scans. Higher resolutions can be useful for enlargements. Professional photography - including all film formats, graphic, archival, technical drawings etc choose the highest optical resolution. This is essential for capturing the finest details.

Colour Bit Depth

Colour bit depth refers to the number of colours captured in each pixel. The more bits per pixel, the more colours the scanner can reproduce, resulting in more detailed and vibrant images.

• 8-bit grayscale scanners capture 256 shades of grey, sufficient for black-and-white documents.
• 24-bit colour depth can capture over 16 million colours, which is the standard for most home and office scanners.
• 36-bit colour depth can capture over 68 billion colours, necessary for high-end, professional image scans but can result in much larger file sizes.

How Much Colour Depth Do You Need?

For most users a 24-bit colour depth is adequate, as it balances quality with file size. For professional photographers or designers may require 36-bit or higher colour depth to ensure the most accurate colour reproduction, though this will increase both file size and cost.

Scanner Types

• Flatbed Scanners - These are versatile and handle most types of media, including photos, books, and documents. Ideal for general use.
• Sheetfed Scanners - Great for office use where you need to scan a large volume of documents quickly. However, they are less suitable for delicate items like photos.
• Portable Scanners - Ideal for scanning on the go but may offer lower resolutions. These are suitable for occasional use or light document scanning.
• Overhead Book Scanners - specialised document scanners uniquely designed to digitise books with efficiency. Unlike traditional flatbed scanners, these scanners capture pages from above, enabling non-destructive scanning without the need to unbind or damage books. The ScanSnap SV600 and IRIS scanners are good choices.

Resizing Images

When scanning images, resizing is important to balance quality and file size: Downsizing: If you're scanning at a high resolution like 600 dpi but only need the image for web use, it's best to resize it to 72 dpi using photo-editing software like Adobe Creative Suite. This saves space and reduces the strain on your system without compromising visible quality. Upsizing (interpolation): Be cautious, as increasing image size through interpolation can result in loss of quality. It’s better to scan at the resolution needed for the final output from the start.

Make an Informed Decision

When purchasing a scanner, consider the following key elements:

• Resolution - Choose based on what you'll be scanning most often. Basic text documents require less resolution than professional photo scanning.
• Colour Depth - Balance between your need for colour accuracy and file size. Most users will be satisfied with 24-bit depth, while professionals may require more.
• Scanner Type - Pick a flatbed, sheetfed, or portable scanner based on your workflow and the types of documents you handle. If your scanning needs require more than one scanner type there are options. A selection of document scanners are multi-functional. The Kodak Alaris S3060F A3 production scanner includes an A4 flatbed unit, perfect for scanning fragile documents and bulk scanning documents, at high speed, using the automatic document feeder. Kodak Alaris are currently offering huge price reductions on the S3000, S3100 Max and i4000 series A3 document scanners and service warranties.

By thoroughly understanding your scanning needs, you can select a scanner that fits your workflow, ensures high-quality results and avoids unnecessary overspending. If you would like additional information or advice, on which scanner would best suit your business needs, please contact us.

Don't get frustrated with technical acronyms - view our Document Scanner Jargon Busting blog post.

23/10/2024.