Scanning 101: Part 1 – Configuring Your Scan Software and Using DNG
Hey all, today marks the first in an on-going series on LifeInDigitalFilm focusing on the art and science of scanning film. Unlike most scanning resources on the web, I am going to focus on scanning for a RAW workflow, targeting Lightroom and Adobe Camera Raw in particular. Today is a short introductory piece, but for those adventurous souls out there, this may get you a quick jumpstart into scanning for RAW-style processing.
Normally when most people scan film, they are doing so to simply produce an output JPEG or TIFF, and most recommend scanning in at the resolution and color depth required for desired output. However, after shooting digital and discovering RAW, it seems an absolute shame to throw away perfectly good data but scanning at a lower quality than is capable by your scanner. So, my recommendation is to max out on the settings in your scan software before you start scanning. You can always throw away unneeded detail when processing, but you cannot magically bring back detail you chose not to scan in the first place.
So let’s look at some basic settings that you should pay attention to at time of scanning. Most scanning software will allow you to use these suggestions and most all modern scanners are capable of using these settings. If you find your scanning software lacking, I highly recommend you check out Hamrick’s VueScan. It is high-quality software at an extremely affordable price, and will most likely work with any scanner you own.
Color or Black and White
This seems obvious; if you are scanning color, choose a color scan mode. Scanning black and white, select a monochrome scan mode. However, I don’t see things so cut and dry. When you are scanning color negatives or slides, obviously you want to configure your scanner to scan color … scanning color as monochrome is borderline insane. On the other hand, when scanning black and white film, I say scan in color mode anyways. Let the disagreements flow.
Here is why I propose scanning black and white negatives as color images … more data. Scanning monochrome images records only one color channel, black (and in direct opposition white). However, most all black and white negatives will have a certain amount of stain in the negative. It may be almost unnoticeable to the eye, but it is there.
I have not exactly figured out why, but scanning in this stain, and its affect on the actual image leads to an improvement in image quality in the end. I believe the stain makes it easier for the scanner to pull out fine tone, but I could be wrong. Either way I get better results in a RAW workflow by scanning my B&W negs in as color images. Plus, the stain itself can often contribute to an even more intriguing image, kind of a built in image toning.
Color Depth / Bit Depth
Depending on what software you utilize, this setting can be referred to as either Color Depth or Bit Depth. This refers to how many bits of data are assigned to each pixel for each color channel. Scanning software tends to refer to the bit depth in terms of the combined bits for all color channels, Photoshop (and most other software) refers to bit depth in terms of the amount assigned to a single channel. In other words to create a 16-bit image in Photoshop you must set your scanner up to scan at 48-bit (16-bit/channel x 3 color channels = 48-bits). Traditionally, most recommended to scan negatives or slides in at a 24-bit color depth to result in an 8-bit JPEG, however that removes way too much data to properly adjust your scans in Lightroom.
Even if you do not feel you image requires the additional leg room a higher bit-depth provides, Lightroom craves that extra data. The extra color data that can be stored in a 48-bit file allows more available colors in your image and finer gradations, both of which are vital to treating your linear TIFF image like you would a RAW file in Lightroom or ACR. Don’t cripple yourself by scanning at a lower bit-depth to save on file size … storage is cheap and time is money, save on time editing by using more disk space.
Now this is dependent on your scanning software, VueScan Professional and SilverFast both can allow you to define your output color space. Lesser software may limit you to outputting in sRGB but if you can you want to create your final output in ProPhoto RGB. This is a shame, as your scanner is most likely able to scan in many colors that fall outside of the sRGB color space, and you are throwing away that color data, even if you are scanning to a 48-bit file.
So, if you are able to, be sure to set you output color space to ProPhoto RGB and if that is not an option, Adobe RGB at the very least. Most modern scanners internal color space will fall between those two color spaces, with only the high-end scanners able to reproduce colors filling or exceeding the ProPhoto RGB gamut. You simply do not want to waste that data if you can avoid it, Lightroom will eat it up if you can serve it up.
Another argument for ProPhoto RGB, Lightroom’s native color space Melissa RGB is based off ProPhoto RGB. Therefore it is the logical best choice. Read more on Color Spaces in my piece from the X-Equals+Digest.
This gets tricky, as it is different for every scanner, as each has its own optimum resolution, which is what you should use. I will cover this more in depth in the actual series, but if you are able to scrounge up your scanner’s native resolution on the internet, that is the most likely resolution that you would want to scan to. A scanner’s native resolution is the highest resolution the machine can produce without interpolation ( i.e. uprezzing). You simply do not want to have your scanner resizing your image with interpolated pixels when you can do a far superior job yourself with Photoshop or Genuine Fractals. You will get sup-par results.
For me, using my Epson V500 of Plustek OpticFilm 7200, I find the optimum resolution for scanning 35mm film to be 3000-3600 DPI. Although VueScan offers me much higher resolution options, the image quality starts to fall off past this point for both scanners. Scanner manufacturers advertise their Maximum resolution, not their Native resolution, so check to see what the masses recommend for your scanner, or run a series of tests to see what looks best to you at 100% zoom in Photoshop.
Next, there is only one option for you to even consider for you output format for your scans … TIFF. TIFF is capable of handling your 48-bit scans without losing an ounce of data. TIFF can handle and color space you can throw at it, including ProPhoto RGB, which needs to have a 48-bit file to be effective. TIFF is superior in almost every way to JPEG. JPEG can only handle 24-bit scans, as it is an 8-bit format. It would be dumb to scan in at 48-bit only to save as a 24-bit file.
You will need to make sure that you set the TIFF bit-depth to 48-bit (will sometimes be listed as 16-bit), otherwise you may inadvertently save your image to a 24-bit file anyways.
Another plus, TIFF wraps up nicely in the DNG format.
So, to generate the best results from your scans when using Lightroom as your primary editor make sure to set, scan and save files with the settings discussed.
- Scan Mode – Color
- Color/Bit Depth – 48-bit
- Color Space – ProPhoto RGB
- Resolution – Your scanner’s native or optimum resolution
- File Format – 48-bit TIFF
The next section is optional but highly recommended.
After scanning your images in with these settings, import them into Lightroom. When importing, make sure you choose the import option Copy photos as Digital Negative (DNG) and add to catalog. This will wrap your TIFF files and compress them into the Adobe DNG format. This adds a few layers of convenience and security to your workflow.
Most will ask, why convert TIFFs to DNG, its not like the magically become RAW files? That is true, they are still simply TIFF files, just wrapped in all the metadata goodness of the DNG format. Here is my list of reasons for converting to DNG on import.
- Your original scans will stand out from regular images.
- You cannot accidentally overwrite you TIFF when wrapped in DNG. The TIFF stays just the way you scanned it, only metadata changes.
- Metadata edits in Lightroom or ACR can be saved right to the DNG file, not stuck in a sidecar XMP file.
- DNG has some dang good compression, squeezing down those huge TIFF files a bit, in a lossless manner.
- Did I mention that DNG will differentiate you original scans from other TIFF files, making them stand out to you?
- In a way, although these are rendered images, these scans are the equivalent of RAW data … they are the starting point from which you will make further edits, give them worthy recognition.
- It is another excuse to use DNG in your workflow.
- Plus, you can call the above specs for a TIFF scan wrapped in DNG Film DNG or fDNG (I would call it RealRaw, but that might piss off Ken Rockwell).
I always convert my scans to DNG before further editing. It protects the vital data in the scan from the rigors of Photoshop editing. Even if I accidentally open a scan DNG in Photoshop, it will fire up ACR before allowing me to edit. Without the DNG wrapper, I could accidentally make edits and save, overwriting the TIFF file. DNG prevents that.
In general I like DNG and it works well in my workflow to use it for my scans as well as my DSLR RAW files. And if you use VueScan, you can avoid the Lightroom conversion and save directly to DNG from VueScan.
Although not the deepest article on scanning, I think that this may help many of you get started in scanning for Lightroom editing. All this will be covered more in depth, with a variety of scanning software, as this series continues culminating in my ebook on scanning. Stay tuned for more, and hopefully this gets you thinking about your scanning workflow.