What is an Aperture Card? And Why Scanning?
An aperture card is used to store images that have been reduced in size from the original. There are many different types of cards in use today. Yes, they are still in use today.
Not everyone has seen or knows what one of these cards looks like. Some cards only have the cutout for the image itself, while others contain a lot of information about the images. Some cards have holes (Hollerith) that the machine reading the cards can interpret for the user. Here are some examples of aperture cards:
Standard Card
Hollerith Cards
As you can see, the standard card shows just image window on the card, while the Hollerith cards have more information to capture from it. This information can be captured during scanning in order to speed up the indexing of the cards depending on your software. Some of the fields you may need to capture for indexing are the image title, date of the image, the revision number, or any other info on the card. Some cards can be color coded to denote specific departments or locations.
How to Scan Aperture Cards
To scan, or image, an aperture card you will need specialized equipment. This scanning machine can be a manual process with the operator scanning each card and changing them out of the machine themselves. It can also be an automatic practice with the operator placing a stack of cards into a “hopper” and the machine feeding them through the process. Each type of scanning process has good points and bad points. What it all comes down to is speed (your deadline) and cost.
The manual process takes much more time and man-hours. However, being able to check each image for clarity, accuracy, and any other issues does make for a better image quality. If your images are sensitive and need special care, manual scanning is the right choice.
Automatic scanning is a much faster process, yet does not slow down (or change settings) when images need extra attention. Images that are darker, or lighter, than the images before and after it will have a washed out effect if too light. They will come out too dark to read if too dark. This process does not take into account these gradations of brightness. It does get through 3x as many images in an hour than the manual scan does though. This makes it the go to process whenever this is not an issue. The cost differential is also a major reason why auto scanning is the preferred method.
Do’s and Don’ts
One of the most overlooked aspects of aperture card scanning is the thickness of the cards. Each card manufacturer might have specs to follow when making the aperture card, however, this does not always equate to standardization across the industry. We have had cards with extra tape on them. We have had cards made from the same manufacturer and still have them with different thickness.
All of this is to say, pay attention to the thickness because your scanner knows. Your scanner can tell the difference between the cards. if you have set your gauges on your equipment to a specific depth of scan, when the differing cards go through the machine, you will get a card jam.
Another issue you may find with aperture card scanning is sticky cards. This can be for many different reasons but the end result is the same, cards that stick together and cause a jam in your equipment. The older the cards are, or the longer they have been in a less than desirable storage location, the more likely the cards are to stick together.
The paper stock combined with the adhesive from the image film make the cards tend to merge into one giant block of card after a while. Fanning your cards out before you scan is the best defense against sticky cards. Just a simple card shuffle will do. Be careful not to get the cards out of order though. Since most cards are architecture drawings or engineering schematics, the order of the cards may matter quite a bit.
At The Document Group, we have over 10 years of experience scanning aperture cards, microfilm, microfiche, negatives, and slides. Let us help you turn those outdated media formats into something that is digital, searchable, and easier to use. Call us today!
