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1 Message


70 Points

Mon, Sep 16, 2019 11:20 AM

Neutral Base Curve

There always is a base curve applied to all images in both Lightroom and ACR, that can currently not be turned of at all... I need the correct brightness for my work. We are using in 32 bit HDRIs for lighting in 3D rendering. This means they need to be absolutely unedited in their colour and gamut. Right now I need to use different software (RawTherapee, darktable) because this degrades the quality of our HDRIs to an unacceptable point. But I would like to return to ACR/Lightroom as the TCA (chromatic abberation) removal is a lot better in these... (I'm using Nikons 8-15mm lens and it's not even supoorted at all by darktable and RawTherapee. Please give us access to disabling this base curve, so that we can start using your products again.
The following blogpost of a friend of mine features an image of what this issue looks like on an example image (no edits lightroom vs no edits in other software)


1.9K Messages


22.8K Points

a year ago

What you write isn't accurate in a number of ways. 

First, you can produce scene referred output** from ACR and LR with a linear gamma. See:

Next, you seem to be a bit confused about 'correct' brightness. No such thing really. Brightness is a subjective perception of a color for humans. Brightness- perceived amount of light (from self-luminous things). Your camera isn't behaving this way. Brightness is the perception of Luminance.
Lightness is perceived. Brightness relative to some average level in an image or environment.Video showing the differences between Lightness and Brightness:


Author “Color Management for Photographers"



2.3K Messages


38K Points

a year ago

You can create a linear tone curve version of any camera profile using the DNG Profile Editor (DPE). Scroll down at the below link to 'DNG Profile Editor (September 2012).' apply the below setting in the DPE Tone Curve tab. This essentially removes the base tone curve from the camera profile. You'll need to reapply  the tone curve to the HDR output file.