32 vs 16 bit oddities

[TEcHNOpls]

Hi,

is this desired behavior I'm seeing in AP?

When working with 32bit file (DNG from DxO11) the changes to colours seem very extreme (even in develop persona, black piont+1% has a huge impact).

Whereas working in 16bit is fine. Is this ok or not? See attached curves for example.

[James Ritson]

Hi, sorry for not replying sooner - that behaviour is expected since the adjustments behave differently to account for the (potentially) huge tonal range in 32-bit float. An image developed from RAW still contains a relatively small amount of tonal range compared to what 32-bit can hold, so the adjustments will seem very sensitive.

 

Things even out a bit if you're working with an HDR image or 3D render that has a large dynamic range. For all scenarios though, that's why you have Min and Max input options on the Curves dialog - these allow you to restrict the adjustment to particular areas of the tonal range (e.g. 0.2 to 0.8), and as a result the spline graph adjustments will be less sensitive.

 

I might just ask if there's a reason why you're working in 32-bit? (Your image doesn't look like an HDR merge). For most single-exposure imagery I'd argue the benefits of working in 32-bit as opposed to 16-bit are negligible, with the exception of some edge cases like astrophotography... hope that helps!

[TEcHNOpls]

Hi, thank you for your feedback/explanation, I was thinking around these lines.

For me, for now, it's 16bit for better gamut (as opposed to 8bit) I believe. I was thinking/testing if 32bit would bring any benefits to my workflow, and noticed these, that's why I was asking.

[lepr]

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[TEcHNOpls]

@owenr, thank you for this explanation too.

[lepr]

A UX fail: the developers have neglected to make the controls behave logarithmically when the user is manipulating a linear image. The current user experience is that a tiny adjustment at the left end of the histogram has an almost uselessly massive impact on the appearance of the image and a massive adjustment at the right end has an almost uselessly tiny impact on the appearance of the image. Logarithmic controls would give the user the sensation of having equally useful control all across the histogram of a linear image.