How to scan documents
We appreciate old documents, we call for the digitization of archives so that we can consult them and prevent them from disappearing someday, but what about our own collections and those within our reach?
With an average equipment, a standard scanner or a digital camera in use, it is possible nowadays to obtain magnificent digitalizations of documents of all kinds.
Let’s look at some recommendations and lead by example!
First decision: Desktop scanner or digital photographer
The desktop scanner is always the best option for obtaining perfectly framed images, focused and without interferences of ambient light, the latter factor that can become a nightmare in the case of digital photographs.
Against it we must point out that it is a notoriously slower method and that we cannot or should not always place certain documents in a scanner, since accommodating them in the scanning screen can be impossible or harmful when we handle bound elements or in general susceptible to deterioration when carrying out this maneuver.
The advantages and disadvantages of digital photography can be deduced from the reverse of the above, highlighting the freedom that the camera offers us to digitize any document, whatever its size, state or shape.
The autonomy of this system is also important, since we will not always be able to have the documents to process them in our workplace or move the scanner to the place where they are; the camera turns us into universal digitizers.
In principle, whenever we have the means and time, we will opt for the table scanner, especially in the case of photographs or documents that require the highest possible quality.
However, when it comes to a voluminous set of written documentation, digital photography is a much more agile option that will provide us with adequate results.
Image formats: TIFF, JPG, RAW
We must be aware that all formats are not the same. A widespread standard is JPG whose great advantage is also its weak point as it generates images that consume little space through the application of a compression algorithm.
Every time we edit a JPG image and save it, even if it’s for just one rotation, a new compression will be made.
Something invaluable if it is done a couple of times but that can become notorious in successive editions. However, these files can only be opened for consultation indefinitely without any loss.
TIFF is a veteran format that has been repeatedly recommended by professionals and public agencies to store digital images because when they are generated compression is not applied or is very mild, while subsequently can be edited again and again without deteriorating the quality. The downside is that files have a noticeably higher weight than JPGs.
Finally, in the case of professional or semi-professional digital cameras it is possible to store the images in RAW format, literally image format without modifications, also known as digital negative.
It is an option that we do not recommend since it will overturn us the photo as it was made, without the filters of improvement that apply the cameras, reason why it would be necessary to treat them later.
Yes, it is very suitable for advanced users in photography who are looking for the best quality.
These are the reference formats that we will have to handle. If you are aware of the possible compressions performed by JPG, we believe that it may be the best option to perform the entire process because you really get very good images with a more than reasonable size.
However, we recommend always keeping a master file of the original images in case we need to resort to them in case of any damage or deterioration of the copies.
Only for the cases in which we worry to obtain the maximum quality and fidelity we believe that it is suitable to resort to the format TIFF in scanners or RAW in digital cameras, knowing the necessities of space and the time that later we will need to adapt them to other more manageable formats.
The basic parameter when scanning will be the resolution we want to obtain, measured in dots per inch (dpi).
The higher the resolution, the more images can be enlarged without deterioration, but at the same time we will generate larger files, reaching a point where the higher resolution will not bring substantial advantages.
In the case of old documents, folio or A4 the standard recommendation is to set between 200 and 300 dpi.
If you are dealing with very sharp documents, 200 dpi may indeed be sufficient, but we recommend adopting 300 dpi as the standard to ensure the result.
Even medium or difficult to read documents can be increased up to 500 or 600 dpi. Even if they are only written documents, it is always advisable to scan in color.
For the digitalization of photographs, plans, scrolls with illustrations, etc obviously we will always choose the option of color and the basic resolution we will elevate it to 600 dpi, being able to be increased up to 1200 dpi for optimal results.
Light and digital photography
As we have already advanced, light is a crucial element for digital photography of documents, although our eye cannot appreciate it, inadequate artificial lighting can generate marked shadows in the images.
Whenever we have enough natural light, let’s opt for this option but, in case of doubt, it’s convenient to carry out previous tests. It may be helpful to set the auto flash position on the camera to observe if it fires, in which case we will know that not enough ambient light is detected to take pictures.
If we have to make them with artificial light the ideal is to have a multiple lighting system, from different angles, to provide an effect as uniform as possible. We can manufacture a scanning platform by placing two, or rather four, spotlights fixed with a 45º orientation on the document.
Other digital photography considerations
The quality of digital photos will depend on several factors such as the lens, the sensor, the camera processor and the resolution (megapixels, mpx) as well as the configuration of the camera itself, it will be convenient to know and take advantage of all these features.
However, let us consider that for a good photograph of an A4 document it is advisable to set a resolution of 6 mpx.
The camera must always be centered so that it focuses on the center of the document. It is also advisable to anchor the camera to a tripod or bracket to speed up the process and avoid blurred images. A remote trigger will also be of great help in mass processes.
If possible, let’s look at some test images on a computer before doing a full photo shoot. Not always a crisp image on the camera screen then shows enough quality.
Let’s always rule out the use of flash as it will always unbalance the light in the image and therefore lead to bad results.
If we are going to carry out a long session of photos out of our house we foresee the logistic aspects; to count on batteries or batteries of spare and to take loader, as well as to have an ample space of storage, well in memory cards or being able to unload the photos during the session in some other means of storage.
Also, when we are going to take hundreds of photos, let’s remember to identify as much as possible what each document is and where one ends and another begins. A simple solution can be to insert a blank photo between each set of images, so that later we will know how to quickly identify the groupings.
Once the scan has been made or photographed, we must store the original images in an orderly manner and for this we can use the file folders, using as many subfolders as necessary to clarify the content.
Having done this, let’s be prudent, let’s not leave the task of creating a complete copy and storing it in some other safe place to prevent losses.
Then it will be time to consider whether to process the images, if it is convenient to group them in PDF files or similar, study them in detail, share them, etc. but we have already done the fieldwork to ensure it.