Einstein’s legacy (http://www.einsteinslegacy.com) has announced Monochrome 3.4.1, a feature update to their post-processing application for macOS.
It converts batches of images to grayscale, giving you control over the conversion and post-processing effects. You can create a consistent set of output images that can be shared and printed in a variety of ways. Version 3.4.1 contains a collection of bug fixes, a new user interface and more than two dozen new image effects.
Monochrome 3.4.1 requires macOS 10.11 or higher and costs $19.99. It’s available worldwide exclusively from the Mac App Store in the Photography category.