This can be emulated in darktable by using either the exposure module with manually created masks, or by using the tone equalizer module, which generates a mask using a guided filter. This saturation curve can be simulated within the filmic rgb module.ĭeveloping a monochrome film in the darkroom traditionally involves “dodging and burning” to control the level of exposure across different parts of the image. As a piece of photographic film is exposed to more intense light, its response will fall off as the silver emulsion becomes saturated. The color calibration module allows the three channels to be mixed into a gray channel by varying amounts, and it includes a number of presets that are designed to emulate the characteristics of some well-known types of photographic film.Īpply a luminosity saturation curve. Different types of monochrome photographic film have different levels of sensitivity to various wavelengths of light, and this can be simulated by giving the three color channels different weightings when combining them together into a single monochrome channel. Map the color channels from the sensor into a single monochrome channel. This approach tends to work with linear scene-referred data from the sensor, and attempts to mimic the response of a photographic film with a silver emulsion. □monochrome conversion □physical approach demosaic, white balance) are automatically disabled. If darktable detects a true monochrome image or one from a monochrome-converted camera (using the “passthrough monochrome” demosaicer) some modules (e.g. By automatically applying this tag and visual indicator, darktable makes it easy to set up filters to single out images for monochrome treatment, and to see at a glance which images in the current collection bear the monochrome tag. The darktable|mode|monochrome tag will be automatically applied to any images flagged as monochrome and, if you have enabled any permanent overlay information on your lighttable thumbnails, such images will be marked with a visual indicator B&W next to the file type information. If any of the above methods result in an image being flagged as monochrome, darktable modules can use this information to present the user with some monochrome-specific module controls and/or apply special processing to the image. Note: You should only use this for images taken on a camera where the color filter array has been removed.Īfter you have imported the image, you can manually flag an image as monochrome (or not) using the metadata tab on the lighttable’s actions on selection module, If you set the demosaicing method to “passthrough (monochrome)”, this discards color information during the demosaicing process, and darktable will flag the image as monochrome. When processing a raw file, one of the first steps is to demosaic the image. You can enable this check in preferences > processing > detect monochrome previews When you import such an image, darktable can automatically flag the image as monochrome based on the preview image.Ĭhecking whether the preview is monochrome slows down the import process, so this is disabled by default. The camera will still capture the full color data in the raw file, but the embedded JPEG preview image will be monochrome. This allows you to visualise what the scene would look like in monochrome through your camera’s liveview screen or electronic viewfinder. When you capture a scene from which you would like to produce a monochrome image, it can be helpful to put your camera into a “black & white” creative mode. If the image was taken using an achromatic camera, the image will be automatically flagged as monochrome. When importing an image, there are a number of properties that can be used to indicate that the image requires a monochrome treatment: □importing and flagging images as monochrome These approaches, and other monochrome-related features in darktable, are discussed in the following sections. There are two main approaches to this conversion:Ī physical approach, where we attempt to simulate how a silver-based photographic film emulsion would react to the light captured at the scene.Ī perceptual approach, where we develop a color image and reduce the color saturation in a perceptual color space such as CIE Lab. While there are some specialized/modified cameras with a truly monochrome sensor, most still use a regular camera to capture a color image and transform it into a monochrome image during post-processing. Photography has a long history of producing monochrome images, and many still enjoy this aspect of photography.
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