ACR 6.3 Bug - Introducing Noise

Question

I just upgrading from CS4 to CS5 the other day for PS, including 6.3 of ACR.  I've had something happen in the workflow of the images I'm working on, but you can duplicate it below (or tell me if you can't).
In PS, create a 200x200 pixel image.  Fill with white.  Save as a .tiff .  Close the file.
Open Bridge.  Find file.  Open in Camera Raw.  No adjustments.  Click open, to open it in PS.
Back in PS, make a levels adjustment layer.  Drag the black point all the way to the right.  Check out the random grey noise like pixels that have suddenly appeared everywhere.  Try it with default settings in ACR, change anything you want.  I can't get them not to appear.
I don't think this is just me.  Anyone else want to verify?

Answer 1

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sjlocke215 wrote:
I would prefer not to add another two steps to my workflow by processing this or that way to get around it.
I agree that the dithering regardless of settings is a bug - the Camera Raw color transform should respect the Color Settings choice you have made in the Color Settings preferences panel of Photoshop, and it does not:
Are you opening your images into Photoshop?
If you set the converter to output 16 bit data, then just work in Photoshop with the 16 bit data, then Save As or Save For Web & Devices there aren't really extra steps...  And all your processing will be in the more accurate 16 bits/channel color depth, which yields better quality images overall.
I would also suggest converting to the ProPhoto RGB color space to avoid channel clipping due to gamut issues.
It's pretty clear that because of quirks in Camera Raw, extra steps may be warranted to get the best possible image quality.
-Noel
P.S.,  There was another thread where this was discussed extensively, mid to late last year.