Tone curve in Develop Persona

[Littletank]

I have observed that in the Develop Assistant in the Develop Persona there is the option to apply or ignore a Tone Curve to the image when it is first developed from the RAW file. Could someone please explain the objective of this tone curve? I ask because my colour perception is rather poor and I intend to convert the developed images to black and white after development and it is important to me that the black and white points are set correctly.

[James Ritson]

Hey Littletank, the tone curve is simply a way of presenting a (hopefully) good tonal starting point when you develop your RAW file.

 

RAW files go through a number of operations before the end user sees the result - including a transform from linear light to display referred, which includes gamma correction. On top of this, a tone curve is added to produce a more palatable result that looks similar to the output you would get from in-camera JPEGs. Choosing not to apply the tone curve skips this step, so effectively you'll see a flatter image with less contrast.

 

In my RAW workflow I pretty much always take the tone curve off. Along with the Highlights slider (which has a more pronounced effect without the tone curve), this allows me to shape the image tonally exactly how I want. I'd recommend giving it a try, especially if you're working with images that were taken under tricky conditions - low light, bright skies, etc.

 

Pretty much any RAW converter will add a tone curve to the image. Some software, including Photo, allows you to control this step if you prefer to work without it. Hope that helps!

[Littletank]

Thank you very much indeed for this quite comprehensive answer and, as I think it better to start with a flatter image, the tone curve stays off.