We do a lot of talking about digital archaeology, metadata or the Cloud. But the truth is, when it comes to Cultural Heritage, very often we have to deal with archives (or messy piles) of physical memories, presumably with relevant access or preservation issues, which is why the digital documentation we are able to produce from those records can have an enormous impact on the practice of research and circulation.
One thing is especially clear with printed photographs: no matter how carefully they are stored and protected, those pictures are slowly going to decay.
CoDA’s staff had to face the problem of digitizing printed photographs for a few projects, e.g. while working for the S.F. Presidio Archaeological Trust … but, hey! we’re also humans, and we all went through panic moment when we wanted to digitize some old precious travel- or family picture “just in case my house burns down”.
So here is a couple tips we learned throughout our projects; we’d love to hear your thoughts and learn your tricks!
First of all, there are tools out there that allow you to scan photo slides or negatives, which may be a preferable choice whenever possible, however today we will be rather talking about scanning prints, and doing so using a non-professional scanner.
Oh, and please, do this for me: resist the temptation of just taking pictures of your pictures! At best, the lens distortion effect would be doubled, colors in the resulting image would result influenced by lighting conditions at the moment of acquisition, not to mention the additional noise that could be generated throughout the process. (They can still be useful as a help for context and cross referencing to the physical archive…)
Choose the right resolution
If you are familiar with Moore’s law, you know such thing as “the right resolution” depends on the available technology (a blog post from the early 2000s would probably tell you acquiring images at 300 DPI is even too much…), but it’s also related to your storage capabilities and the physical size of the original image. Choosing a higher resolution is particularly important for the purpose of creating a photo archive: high-quality images do take up more space, but they will give you better options down the road.
Provided that you have enough storage space, you can stick to your scanner’s maximum optical resolution, and only use higher values if you plan to resample the image back to a smaller size later, e.g. if your image needs descreening (which is not the case for printed photos but rather newspaper clippings). We sampled different resolutions up to 1200 DPI for this example.
Choose the right format
Any scanner will give you the option to output in different formats. While you should be keeping an eye on storage needs and the expected use of the file, our suggestion is you store a digital negative of your image in an uncompressed format such as .bmp or .tiff. While you can always compress this into a .jpg file later, this will store richer color information from your photos.
For the chosen example, choosing a 1200 DPI resolution the size would vary from 13 MB (.jpg) to 109 MB (.bmp)!
Enhancing the image
Unless you are using a professional photo scanner, we don’t suggest you make corrections and improvements while scanning. You should rather enhance or restore your image later with an image processing software of your choice, which will give you more control and the option to try different solutions through non-destructive editing techniques.
Cropping is also something you shouldn’t bother too much about while scanning, to avoid losing portions of your image in case it’s not placed exactly orthogonally. Same goes for sharpening, exposure, even rotation: they all could determine a slight quality loss in the scanning process, and can easily be corrected later.
Don’t misplace your digital negatives
Once you have created your digital negatives, you should embrace some basic archiving best-practices: assign them a permanent storage location, include them into your usual data management workflow (e.g. adding rich metadata to help retrieving them later), and most important, create a permanent link between the file and the physical original, by cross referencing the two archives.
Do you have other good practice tips to suggest? Get in touch or leave a comment below!