Screenshots only use 8-bit depth color

Originator:ricciadams
Number:rdar://27942232 Date Originated:
Status: Resolved:
Product: Product Version:
Classification: Reproducible:
 
macOS has supported 10-bit color since 10.11.2 (per https://developer.apple.com/library/mac/releasenotes/MacOSX/WhatsNewInOSX/Articles/MacOSX10_11_2.html) and this was further refined in 10.12 Sierra.

I am using a supported device (iMac, Retina 5K, 27-inch, Late 2014) and I see a pixel depth of ARGB2101010 in System Information.

However, screenshots created with the built-in Grab tool, the screencapture command-line tool, and keyboard shortcuts are always reduced to 8-bit depth.  In addition, both the built-in Digital Color Meter application and the Pixie developer tool show banding in gradients.  Third party tools also show banded gradients, which I assume is due to a reduction to 8-bit depth.

Steps to Reproduce:
Take a screenshot on a Mac which supports 30-bit depth.  This can be done using Pixie, Grab, screencapture, Digital Color Meter, third party tools, etc.


Expected Results:
Screenshot doesn't lose color depth fidelity.  Gradients are smooth.  Screenshot file is saved as a 16-bit PNG.

Actual Results:
Screenshot gradients have slight banding.  Screenshot file is a 8-bit PNG.

Version:
10.11.2
10.12 beta 6

Notes:


Configuration:
iMac, Retina 5K, 27-inch, Late 2014

Attachments:

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Note: I filed 26885406 to cover the lack of 10-bit in public API.  This bug is about Apple's own programs having the same issue.

Comments


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