Process in which the scanner operator visually monitors the scanner’s output while digitizing each roll to ensure that no images are skipped, cropped incorrectly, etc. Attended scanning is usually expensive and, as it’s performed “live” while the scanner is digitizing the rollfilm, it is still prone to human error — if the operator looks away when an image is improperly output, they won’t catch it. Creekside Digital performs lossless scanning instead, at no additional charge — we can capture the roll in its entirety and perform our frame detection, QA, and image output after the scanning is complete, so you never have any skipped or poorly cropped images.
The number of colors present in the images of your converted microfilm. Creekside Digital gives you two options: bitonal (two colors — black and white) and 256 color grayscale. Which color depth you choose depends on your project’s requirements, the content of your documents, the intended use of the images, etc. Also remember that grayscale images are significantly larger than bitonal images as more color information is captured, so they will have greater storage requirements (and higher media costs).
Removing unwanted areas from an output image. Cropping is often used while outputting images of scanned microfilm to reduce borders or excess space between the edge of the image and the scanned document.
Removal of any angle present in the document as it appears on the rollfilm in order to make its edges parallel with the edges of the image. Deskew essentially straightens any “crooked” (skewed) images appearing on your rollfilm.
A filtering process which removes noise from images without blurring edges. Despeckling attempts to detect complex areas and leave those intact while smoothing areas where noise is more noticeable.
Simply put, the contrast selection used to adjust the recorded image. In microfilm, as with other photographic applications, the term “gamma” is used to describe the relationship between the density of the film image versus the film’s exposure to light. Gamma correction allows us to adjust the scanned images’ contrast for a variety of applications: to produce more natural-looking images, to “lift” or enhance text on dark film to make it more readable, to compensate for under- or over-exposure, etc.
Optical Character Recognition. OCR is a type of software designed to extract text from images (for example, digitized images of your rollfilm) and output it to a file such as a PDF or text file. Creekside Digital can run OCR on your digitized rollfilm and create searchable PDF files, or generate high-resolution archival TIFFs and separate text files of the OCR output. Note that while OCR works very well with typewritten text, it is limited in its ability to recognize hard written (cursive) script, particularly on older documents of dubious quality.
Positive / Negative Film:
Positive microfilm has tonal values which are the same as the original; light areas are recorded as light, and dark areas are recorded as dark. Negative microfilm, as you’d expect, is the opposite; light areas are recorded as dark and dark areas are recorded as light. Scanning from negative microfilm can reduce the appearance of flaws in the microfilm images.
The ratio between the size of the original document and the size at which it appears on your rollfilm. For example, an 8.5″ x 11″ document filmed at a 25x reduction ratio will appear as a .34″ x .44″ frame on the microfilm. It is helpful for the scanner operator to know the reduction ratio of the documents on the rollfilm as it makes setup time much faster.
Your digitized images can be resized according to your parameters (e.g., variable width with maximum height of 350 pixels, resize all to 900 x 650 pixels, etc.). Often, multiple images may be output: a smaller thumbnail image at lower resolution, and a high-quality, full-size archival image.
The number of dots per inch (dpi) at which an image is scanned. Images scanned at higher resolutions contain more image information (detail) but also take up more storage space. 300 dpi is the minimum scanning resolution required if you intend to use OCR to extract text from your images. If you’re opting for web presentation, 200 dpi is often a good resolution to use. For example, an 8.5″ x 11″ document scanned at 200 dpi in 256 color grayscale and output as a JPEG with slight compression is approximately 1.5 MB in size. Creekside Digital can digitize microfilm at all resolutions from 100 to 600 dpi.
A process which rotates the output image 90, 180, or 270 degrees from its orientation on the original microfilm. This option is typically used to ensure that all images may be easily read, even if they were filmed sideways or upside-down.
A filtering process which increases the apparent sharpness of microfilmed images. Proper use of a sharpen filter can increase the readability of frames, particularly those which were originally microfilmed slightly out-of-focus. However, care must be used when using sharpen filters as too much of the effect can produce unwanted, exaggerated edges or “halos.”