White Balance using TIFF vs DNG

In the Quick Start Guide for Windows, Step #2 states “Use the White Balance Tool
to Sample The Film Border” but it comes with a caveat, “Skip this step for TIFF scans.”

I’m confused about a few things…

  1. Why do you skip the white balance step with TIFF scans (I was doing this step on my TIFFs and it seemed to do exactly what I wanted)
  2. According to the Film Scanning Best Practices guide, “The recommended workflow for Silverfast is to scan as 48-bit HDR DNGs.” If the TIFF file format is larger and preserves more data than DNG, AND the white balance step is supposedly not required, why is the DNG format the recommended format?

I’m scanning negatives with my Epson V600 using SilverFast, I’ve been auto selecting every frame, then using the “auto” button to adjust color, exposure and contrast settings. I’ve been scanning 35mm negatives at 3600ppi 48-bit color and exporting to TIFFs. I’ve used both SilverFast’s built in negative inverter as well as doing it fully manually using curves, but now I’m looking into Negative Lab Pro.

From what I understand, the RAW DNG format stores the raw sensor readings from the scanner without processing. This effectively means that no color correction or gamma correction have been applied for instance. This format keeps as much information from a scan for Negative Lab Pro to do its magic (color inversion, orange mask neutralization).

When exporting your scan in the ‘regular’ TIFF format, usually the sensor readings are transformed by applying a gamma correction. As a result, the sensor readings will be transformed into values that obey an exponential function in which the darker tones will be encoded more fine grained than the brighter tones (smaller steps in dark tones than in bright tones). When Negative Lab Pro processes such image, dark becomes light and light becomes dark, and, to simplify matters, in effect we lose precision in the dark tones and have excessive precision in the light tones (the opposite of what we actually want in the converted image).

Usually the outcome is not as dramatic as stated above, but for some high contrast images and images with a high density range, you might notice more detail when processing a RAW DNG scan with Negative Lab Pro.

When sampling unexposed film to set the white balance in Lightroom Classic, you help Negative Lab Pro neutralize the orange mask of color negatives. This step is recommendedn, but even if you don’t, most often Negative Lab Pro will be able to digitally develop your raw negatives anyway.

The setting I most often tweak when converting film negatives in Negative Lab Pro, is the white balance. Even when sampling the orange mask in LrC prior to run Negative Lab Pro.