Lab channel black

AZ
Posted By
Arnulf_Zimmermann
Aug 6, 2008
Views
292
Replies
10
Status
Closed
PS 10.0.0.1 fixes the issue, when appeared with camera raw 4.1.xxx, when updating to 4.3.xx lab is black again. Downgrading to 4.1.xx solved the issue again. Don’t know why. But the version of camera raw is really of importance.
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C
Curvemeister
Aug 6, 2008
Is this only for images imported using ACR, or all Lab images?
S
ScottHadley
Aug 7, 2008
It is for images opened with ACR then saved as TIFF or JPG. Sounds like I need to go back to ACR 4.1.
C
corpore
Sep 2, 2008
mmh, I am running PS CS3 10.0.1 and the latest ver of ACR.

I have only just noticed, that on converting RGB to Lab the LAB channel and the image turn black. On enabling softproof (or switching back to RGB), colors reappear.

This is bad.

Fred
C
Curvemeister
Sep 3, 2008
and the latest ver of ACR.

That’s the problem – go back to the previous version of ACR and you should be OK.
RH
Reuben_Hann
Sep 3, 2008
I have been experiencing exactly the same problem and would be quite happy to install ACR 4.1 (I am using 4.5 now), but I cannnot find anywhere to download it. If I Google it, I always end up at Adobe’s download page offering me 4.5. There does not seem to be a source for 4.1.

It would be even better if they would fix the problem, but right now I would just be happy to use Lab again.

Thanks for your help.
C
Curvemeister
Sep 3, 2008

4.1: http://www.adobe.com/support/downloads/detail.jsp?ftpID=3647
4.2: http://www.adobe.com/support/downloads/detail.jsp?ftpID=3730

One of the two above versions should be free of the problem. If you were using 4.1 before, that’s the one to go back to.
RH
Reuben_Hann
Sep 3, 2008
Thanks very much, Curvemeister. The download location worked fine. I installed the previous version of ACR and everything looks great again in Lab mode. I never would have figured this out without the help of folks here on the forum.

Thanks again…
C
Curvemeister
Sep 3, 2008
Glad that fixed it!
F
Freeagent
Sep 4, 2008
Someone should take this over to the ACR forum and see what the gurus say (or if somebody already has, I’ve missed it).

It’s been reported often enough to qualify as a bug, but here’s a typical answer to a poster on the Lightroom blog (linked by Curvemeister):

…I’m afraid you lost me. Lab mode doesn’t relate to Camera Raw. (…) Again, the issues you’re experiencing sound independent of Camera Raw. -TH
C
Curvemeister
Sep 4, 2008
Good point, FA.

I believe it’s been mentioned in the ACR forum, with no response from Adobe that I know of. It’s the kind of bug that deserves being reported several times, with a careful procedure for recreating it.

This afternoon, one of my customers discovered a new wrinkle. The problem went away when he went back from ACR 4.5 to ACR 4.1. He doesn’t use ACR for his raw conversions – he uses CaptureOne 4.

If he left his camera’s embedded Pentax profile in place, conversion to Lab in Curvemeister caused a color shift from blue to purple. If he converted to ProPhoto RGB, the color shift did not occur. Converting to Lab in Photoshop produced no color shift.

It would be interesting for someone with the "black Lab" bug, to re-install ACR 4.5 and see if to ProPhoto RGB before going to Lab made the problem go away.

Who could have guessed that the color engine, or related software, would take some sort of side trip through ACR?

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