Interpolating lines – “double speed” or “speed mode”. This method of scanning increases a scanner’s capture speed, but does so at the cost of image quality. Some will tell you that an image scanned at 300 dpi x 100 dpi will have about the same quality of a scan at 200 dpi x 200 dpi. This is just not true. Your images will look like an old, low resolution FAX. Does the scanner vendor you are considering use compression or interpolated lines to make up for slow scanner performance? Scanners using this “double speed” approach degrade the image quality and OCR accuracy as they have to compress the data and interpolate the resolution. Moreover, images manipulated by this “double speed” approach take the risk of being challenged in some legal applications.

True Optical Resolution is the ability to have one pixel on your camera for each pixel on your source image. This is attained by optically adjusting the focal length of the Lens and Camera to capture at true image resolution, not digitally scaling the image to achieve the desired resolution. Scaling an image creates artifacts that are not desirable, and can be very detrimental to image quality while affecting the OCR ability. Some scanner manufacturers state that they have True Optical Resolution, when they in fact have no ability to adjust the optical path for different reduction ratios and DPI requirements. All they have is one fixed setting. Have you ever noticed that if your LCD monitor is not driven at its native resolution, the image quality is very poor? That is because the image must be scaled to fit the monitor’s native resolution and pixels are dropped or added where needed. Scanners with fixed optical paths can only accomplish different resolutions by scaling or interpolating, which really means to add or remove pixels from the original image. The addition/removal of pixels not only can erode significantly the image quality and the OCR precision but also constitutes a manipulation of the original image that could be challenged in some legal applications.

True Ribbon Scanning can only be done with a line scan image sensor, which captures an entire roll of film or microfiche from end-to-end and top-to-bottom in raw, uncompressed, lossless grayscale and stores it as a single image. This ensures no frames are ever missed by poor detection setup or poor image quality on the film/fiche. Strip scanning saves the image in a lossy, compressed image, which is not accurate to the original. Additionally, any needed image processing has already been performed on these lossy images at scan time, so no changes in image quality can be made after your scan is complete. Are you going to be in trial and error mode getting your image processing parameters adjusted for each roll? Do you really want to do all that rescanning? True Ribbon Scanning requires True Ribbon Files which are composed of data in RAW format, grayscale and uncompressed. Anything compressed is NOT a ribbon file and will not give you the benefits of Ribbon Scanning. True Ribbon Scanning allows you to conduct multiple image enhancements without ever needing to re-scan any image. Not so with strip scanning where the files produced are compressed from inception (hence eroded in their image quality and limiting the scope of enhancement), and if you need to enhance quality even further, then you would need to re-scan those images.

What is your REAL speed to scan, process, QA and then output? Not just how fast a scanner can theoretically capture a roll of film? Strip scanning software (vs. True Ribbon Scanning software) can only Scan or Output, but not both at the same time. This dramatically affects your system throughput. Scanning and processing cannot be done at full rated speed without the addition of a high performance storage system. Will your scanner vendor provide this? Remember that a key component to accurately secure that a conversion project is completed within time and under budget is the Production Throughput and NOT the theoretical scanning speed stated in the data sheets. The strip scanners have a production bottleneck in the image processing step and not in the image scanning. Image processing can take up to twice as long as it takes for the image scanning, therefore, strip scanners theoretical scanning speeds do not really measure the true speed of a scanner. You want to verify – what is the speed to complete the 4 basic steps in your process? a) Image Scanning, b) Image Processing, c) QC , d) Output. Furthermore, you not only want to verify that you have the best Production Throughput in the market, but also the best Image Quality produced with RAW, uncompressed data captured with true optical resolution (without interpolation or scaling).

Does the scanning solution that you are considering include a camera capable of 14 bits internal and a real 12 bits of captured data, a high quality Schneider lens, a strobed LED- based illumination source such as LuminTec and/or various automatic processing options such as crop, deskew, rotate, mirror, user adjustable gamma correction and auto thresholding for variable density film to achieve the best possible image? Can it scan an entire roll as uncompressed grayscale at a high quality True Optical DPI? Does the vendor that you are considering still use old-school dedicated hardware to do image processing, or are the image processing features software – based, enabling flexibility and an avenue for future upgrades/developments? Remember that image quality and OCR precision can be severely affected by the illumination system. The strobed LuminTec approach homogenizes light distribution while diminishing any potential linear image distortions, delivering a pristine image quality while keeping the file size small. True optical resolution is only achieved through optical means and not through interpolation or scaling, and the processing of data using RAW files guarantees the maximum fidelity of an image. Strip scanner vendors cannot deliver those characteristics.