P: Soft Proof Histogram Displays Incorrect RGB Values

Report · Apr 29, 2015

The LR CC Soft Proof RGB values shown in the Histogram are incorrect when the cursor is hovered over a specific area of the image. It does not matter what color profile is used or if the ' Graphics Processor option is enabled or disabled in LR Preferences. The values remain the same and incorrect regardless of the Profile selected in the Soft Proofing panel.

The Soft Proof Histogram appears to display the LR Native Color Space values (Melissa RGB) without RGB data conversion to the Profile color space setting in the Soft Proof panel. Please see this post for further details:

https://forums.adobe.com/message/7489...

Report · Oct 20, 2015

I have tried getting Adobe's attention via Lightroom's forum only to be told they do not review the posts there. So here are links to several posts I have made concerning this problem. I have posted examples so that you can appreciate the issue particularly for a professional studio which depends on accurate RGB values.

https://forums.adobe.com/thread/1936393
http://www.canonrumors.com/forum/inde...

Report · Oct 20, 2015

I can confirm the issue. The RGB numbers are incorrect in soft proof in LR 2015.

Report · Nov 18, 2015

LR CC 2015.3 and LR 6 have a bug in the Soft Proofing feature. Neither will display the correct RGB values in the Histogram window. However, LR 5.7.1 and earlier do. However, when the file is exported to Photoshop the RGB values and histogram are correct. This bug has been discussed in several forums since April 2015. This is an essential component for our studio. We need to accurately evaluate each file to meet our clients needs and to insure the product is properly reproduced. We have not update our production machines because of this bug. And can not update them until it is fixed.

Report · Nov 18, 2015

Make sure your destination color profile is good. We have heard some similar report only to find that the color profile is not wellformed/corrupted. Sometimes it helps to use Apple's ColorSync Utility to repair the profiles.

Is it happening on a particular color profile or happening on all profiles?

Report · Nov 18, 2015

Simon, this is a real bug introduced with LR 2015/6 and happens with all profiles. The RGB display is incorrect. I haven't checked yet in 6.3 but Kim's report seems to indicate it is still a problem.

Report · Nov 18, 2015

Jao - It is still a problem. Simon - profiles are identical in all versions and when opened in Photoshop. It is an color engine problem as far as I can determine. Only work around is not use LR 6.x or LR CC any version!

Report · Nov 19, 2015

The profiles that work fine in PS does not necessarily mean Lr would like it. PS might be using a slightly different API that might be more tolerant. With an EPSON RGB color profile applied, I see Lr read out different RGB values (after conversion) when toggling soft proofing on and off. Does the image render for the softproofing look correct to you? Or the problem is just the RGB read out.

If you can share the color profile somewhere, I'd be happy to take a look.

Report · Nov 19, 2015

You seem not to understand the problem. It is not a profile issue.

Report · Nov 19, 2015

This problem is across many machines in two different studios all using the same profiles all having the same issue. If you read all the other user's experiences you will note they are the same. It does not appear to be a profile issue unless we are all having the same profile corruption across many both PCs and Macs.

Report · Nov 19, 2015

Every profile shows the same RGB values in the Soft Proof histogram. See this post https://forums.adobe.com/message/7493...

Report · Nov 19, 2015

Simon, the display is correct. The RGB readout is not. this is even true for proofing to the built in sRGB and adobeRGB profiles. This is also a problem with every single external profile. LR 5.7 did this correct. 2015 CC and 6 have a bad bug in the RGB display.

Report · Nov 20, 2015

This is not an operator error. This is a software bug. Please accept this.

Report · Dec 03, 2015

Hello All,

I apologize for the delay in addressing this issue (it was unfortunately overlooked and only brought to my attention last week). We were able to reproduce the issue in-house and identify the problem. A fix has been implemented and will be included in the next release of Lightroom. Thank you for bringing it to our attention.

Report · Dec 04, 2015

Thank you Kelly–Much appreciated.

Report · Jan 23, 2016

Team Adobe Engineering I have discovered another issue with the Histogram values when NOT in Soft Proof mode. A 100% Blue Lab 0, 90 -128 (RGB 255, 0, 0) reads 0.1, 90.1, -172.3. The maximum Lab a b values are 127 to -128......-172.3 makes no sense and is incorrect!

Report · Jan 23, 2016

That -172.3 value is kosher for a 'color' value (device value) in a color space like ProPhoto RGB that isn't a visible color. PS truncates to 127 and -128 because those are legal and actual visible color values, B255 in ProPhoto RGB isn't.

>>Can you explain B255 not being a visible color value in more detail?

http://digitaldog.net/files/ColorNumb...