When a scanner bulb turns on, it warms up from room temperature to its operating temperature. When it turns off, it slowly cools down. The color balance of the light is dependent to some extent on the temperature of the bulb, and changes in color balance are more pronounced with less expensive scanners. What this means to you is that the color balance of your scans can change as result of changes in bulb temperature. The first image you scan during a long session may look a lot different from the 100th, depending on your scanner. You may not find this a problem, but here are some tips.
Some scanners leave their bulb on all the time. As long as you wait a few minutes after turning the scanner on before making your first scan, bulb warm up should not be a problem.
Some scanners have an option for "quick" scans and for "high accuracy" scans. With a quick scan the bulb comes on and the scan is made right away. With an "accurate" scan the bulb comes on for about 30 seconds and then the scan starts. Use the latter setting for more consistent results.
If your scanner offers no option other than the bulb coming on just as the scan starts, try scanning at regular intervals - one scan every 30 seconds, for example.
Scanner bulbs also change slowly with age. You can compensate for age changes by calibrating your scanner on a regular basis.
When you are performing an imaging assessment, getting an accurate document count is crucial. You need this number to size equipment, both for imaging and storage. You also need to identify the volume for both primary and exception imaging process workflows--that is the main document type and the outliers. Counting documents is both an art and a science. In fact, an experienced consultant can walk through a facility and get an accurate count with the customer hardly even recognizing that he is busy counting away. Here's an example of how I do it in the field.
I count my documents in linear feet. Whether they are on a shelf, in boxes, in file cabinets, or stacked on a desk, I estimate in feet--2,000 pages per foot to be exact. If I walk into an office with four cubes, I first ask the person giving the tour if all the docs are to be scanned. They tell me which ones to include and which to not include. Let's say for example I see about half a foot on two desks, a foot on the other two. There is 1.5 feet of files in each desk. I open a couple cabinets and see a total of four more feet. Then they have a common wall-mounted three foot three-shelf unit for a total of nine feet.
Then I write down a few other pieces of information such as % density, % duplex (and % color if the customer wants color, and other sizes if present). Let's say the shelves contain all three-ring binders and all duplex; I would estimate 50% density and 100% duplex. That gives me 9 feet x 2,000 pages x 0.5 = 9,000 pages and 18,000 images.
Let's say the remainder of documents are in folders (90% density) and only 50% are duplex. That is 13 feet x 2,000 pages, x 0.9 density = 23,400 pages and 35,100 images.
I always do ask the customer to tell me what they think they have for documents, but I also prepare estimates in the manner described in this article to ensure I get an accurate number. In fact, I once had a customer with two tractor-trailer sized roll-offs full of file boxes. They had a detailed manual count of the documents. I, in turn, performed my quick estimate and derived a number just thousands off of their number (the result was in millions of pages). This system is quick, efficient, and with a little practice, extremely accurate.
Image by adrenalin via Flickr
Acting as a subject matter expert to CompTIA, the owners of the Certified Document Imaging Architech™ (CDIA+) exam, for almost 10 years, I have often provided input ‘from the field.’ One of the areas of contention remains the issue of dividing by 1,000 or 1,024 to reduce a number. I am referring to changing a file size [for example] from kilo-bytes to mega-bytes. Let’s say I have a number, 2,500KB, and I want to reduce it to say, mega-bytes. I could simply divide by 1,000 and come up with 2.5MB, but on the exam that is not one of the multiple choice answers. So now what?! Let me explain why…