When you are next in the market for a large-format scanner, you are likely to find the decision-making process easier if you are aware of the fundamental differences between the two commonly used types of sensor technology – CIS and CCD.

Those initialisms stand for Contact Image Sensor and Charge-Coupled Device respectively.

So, let’s set out the vital things to know about these respective technologies, including their advantages and disadvantages, to help you reach a well-informed buying decision.

Why should you opt for a scanner incorporating CIS tech – and why should you not?

It is in scanners where CIS sees its predominant use as a technology. It involves the placement of an array of small light-sensitive elements very close to the object or document that the user wishes to scan.

The main “pros” of purchasing a large-format scanner using CIS sensor technology include:

  • The thinness and light weight of CIS sensors, which enables them to be incorporated into especially slim and portable devices.
  • The relatively little energy that CIS sensors need. Such lower power consumption has led to CIS sensors being used in battery-powered devices.
  • The suitability for the scanning of documents. A document is, of course, a flat object. Sure enough, CIS sensors are well-suited to sheet-fed and flatbed scanners in which the object to be scanned is in close proximity to the sensor.
  • The ability to quickly capture image data compared to CCD sensors.

There are, though, also some reasons why you might not be so inclined to choose a large-format scanner that draws upon CIS sensor technology. These include:

  • The suitability being restricted to direct contact scanning. In order for a clear image to be captured, the CIS sensors need to be in direct contact with the scanned object.
  • The limited depth of field. If an object is slightly raised from the scanning surface, it may produce a blurrier image the further away it is from the platen glass.
  • The restricted colour range. Compared to some CCD sensors, CIS sensors cannot be depended on to provide such an impressive level of colour gamma and dynamic range.

In what circumstances, then, might CCD tech make more sense for your next scanner?

If you opt for a higher-end large-format scanner, the chances are that it will incorporate CCD sensors, which also see widespread use in professional cameras and medical imaging devices.

An array of light-sensitive pixels is used in these sensors, with these capturing data and then transferring it through a complex process, to produce high-quality imagery.

CCD sensors, then, offer such benefits as:

  • Formidable image quality. You can generally count on a large-format scanner using CCD tech to give you a wider colour range, dynamic range, and heightened detail compared to a device based on CIS tech.
  • Better performance in low light conditions. CCD sensors’ greater sensitivity to light means they can capture good images even when it’s dim.
  • Improved depth of field. Even if objects to be scanned are not in direct contact with the sensor, as long as the scanner is using CCD tech, convincingly detailed images can still be captured of them. This helps make a CCD scanner a flexible device.

So, which type of sensor should you look for in a large-format scanner?

Ultimately, CCD and CIS are two distinct technologies, designed to fulfil different purposes. So, the decision as to which is “best” will depend on your particular needs.

In summary, however:

  • If you are looking for a cost-effective solution for the general scanning of documents, such as CAD and line drawings, CIS will typically be the best choice. It offers affordability and low power consumption, in addition to lending itself well to smaller and more portable devices due to the light weight and thinness of the sensor.
  • If, on the other hand, your intended applications call for particularly high-quality imagery and you will be scanning items with deeper texture – in other words, not just “flat” objects – the higher image quality, wide colour gamma, and broad depth of field offered by CCD is likely to make it the optimal choice.

It should be noted, of course, that one CCD scanner will not necessarily be exactly the same as another CCD scanner in its performance and results, and much variation can be seen among CIS devices, too.

Different scanner manufacturers can also differ in terms of how their devices process and optimise scanned imagery to create the final image output.

Talk to the experts at Prizma Graphics to help you come to a decision

As wide-format specialists here at Prizma Graphics, we would be pleased to discuss your individual requirements and to provide tailored advice.

We can also arrange scanning sample tests and demonstrations, if doing so would help you decide on the best scanning solution for your needs.

Whatever your particular situation may be as you seek out the most suitable large-format scanner, please feel free to contact us by email, or to give us a call on 01296 393700.