Topic: Sky on picture take purple hue before any adjustement

[lbenac]

Hello,

I just purchased Curvemaster this afternoon and my copy of Dan Margulis' book is on its way.
I am using CM on TIF images in CS3.
I copy my background layer to apply CM on the copy.
I notice that as soon as I open CM, set the working space to Lab* and apply without doing any change the sky/mountain on my images take a purple hue which I assume is blue>purple. If I cange within CM from Lab* to any other colorspace than the hue disappears. Of course the reason I purchased CM in the first place is to tackle color/saturation in lab*.
I am very likely doing something wrong but I cannot see what.
Any help would be great.

Cheers,

Luc.

[curvemeister]

Hi Luc,

Is it possible that you are using a newer version of the Camera Raw plugin?

[lbenac]

Hi Luc,

Is it possible that you are using a newer version of the Camera Raw plugin?

Hello,

I have the latest version installed 4.5 but I do not develop with ACR. I use CaptureOne 4 instead and output a 16bit TIF with the camera color profile embedded (Pentax K10D or K20D).
Should I try to develop a PEF file with ACR and export a TIF file with ProphotoRGB or AdobeRGB? In any case I do not want to change raw converter as I really like the work flow with C1.
Should I tried to uninstall ACR 4.5 update? I am not even sure how to do it.

Cheers,

Luc.

[lbenac]

Did a quick test.
1) Same file converted with C1 to TIF with embedded Pentax profile > purple hue in Lab* in CM
2) Same file converted with C1 to TIF with ProPhotoRGB profile > no hue issue
So it look like the issue is with CM dealing with camera embedded profile from Phase One.
Note that converting in CS3 the same file from embedded profile to Lab* does not create the purple hue.
Is there a fix? I have plenty of files already converted of course...:-)

Cheers,

Luc.

[curvemeister]

I would suggest going back to the 4.1 version of Adobe Camera Raw.  It can be downloaded here:
   http://www.adobe.com/support/downloads/detail.jsp?ftpID=3647

Adobe is aware of a similar problem in regard to Lab conversions turning completely black in Photoshop, so the longer term solution is to wait for the version after 4.5, and see if the bug is fixed then.

[curvemeister]

Luc,  If you can email me one of your files with the Pentax profile, I can see if I can recreate the problem.  Send it to mike (a) curvemeister.com

[lbenac]

Luc,  If you can email me one of your files with the Pentax profile, I can see if I can recreate the problem.  Send it to mike (a) curvemeister.com

On its way.
Thanks for the fast response - great support 

[curvemeister]

Luc - I don't believe I received the file, and would still be interested in testing it.

BTW - Adobe has acknowledged the "black Lab" problem, and will be fixing it in the next ACR release.  Hopefully this will also fix the purple sky issue that you discovered.

[lbenac]

Hello Mike,

I just email again to your addres a TIF file with a crop and two layers:
1) background>blue
2)CM Lab>purple
This file is a TIF from a RAW file converted with CaptureOne and with camera profile embedded. note that same conversion but in ProPhoto does create any color shift.

Luc - I don't believe I received the file, and would still be interested in testing it.


Micke, I do not use ACR for my conversion at all but only CaptureOne. How would a new ACR release help?
BTW - Adobe has acknowledged the "black Lab" problem, and will be fixing it in the next ACR release.  Hopefully this will also fix the purple sky issue that you discovered.


Cheers,

Luc

[curvemeister]

This problem was eventually isolated to the camera profile.  In common with other scanner profiles, the Pentax camera profiles do not support a reverse color conversion from Lab back to the camera's color space.  As a result, Curvemeister silently, and incorrectly, converts these colors back to the default working RGB space.

Short term, this means you should work in one of the standard working color spaces, and not a camera or scanner space.  Longer term, I will consider adding a warning messsage to Curvemeister.