I’ve been converting 35mm B&W negatives (approaching 6000) using the following: Windows 10, LR Classic v10.1.1, NLP 2.2.0 (Color Model B+W), using a Sony A7r iii.
I have been scanning in 10-20 rolls at a time and batch converting the images. The conversion takes place after I crop each image to image only. The only adjustment I’ve made after conversion has been to change Tones to LINEAR Gamma, then syncing the Tones. At times, the batch process has been with up to 350+ images.
In doing this, I began to notice that a large collection of images were having contrast issues. I then tried converting some rolls, an image at a time. In every case, the individual images convert with a much better result than the batch output. When I compare the batch vs. individual, I do see the histogram has shifted slight to the left on the batch versions. In Lightroom, I can get the batch version to be roughly equivalent to the individual by decreasing Highlights and Blacks, increasing Whites. Of course, at this stage, the controls are reversed.
In addition, I’ve had a very few cases where the resulting image actually has some Green and Magenta appearing in the histogram. Processing these images individually outputs a true B&W image.
Is this anything anyone else has encountered?