Blend RGB colors using gamma 1.0 issue with group flattening

[heathera66554868]

I just upgraded from my disc copy to photoshop cc 2017.  I'm having huge issues with transparencies changing when i flatten groups.  In this example, the blue is in the background, and the red and green are painted in layers in a group on top.  When I flatten this group, the falloff blend is changing.  I've got my color settings set to "Blend RGB colors using gamma 1.0".  Clearly, this is breaking all sorts of things in my paintings that aren't breaking in my older version.  All layers and group modes are set to normal.

[Sahil.Chawla]

Hi heathera,

Have you applied any blending mode on any of the layers in the group that you are flattening?

Regards,

Sahil

[heathera66554868]

This doesn't fix the bug at all, because this is a directly different behavior than all previous versions.  Flattening groups is a common practice among professionals, and no, there are no blending modes in this example.  Just a simple soft round brush. 

[S_Gans]

I wonder if this is an OS issue, or a graphics card issue. I just tried it on my MacPro - running Mac OS10.5.5 with a NVidia GeForce GTX980, and there doesn't appear to be a difference when flattening a group, or flattening individual layers - or when I tried it with Flatten Using Gamma 1.0 off. I do have PS set to use my Graphics processor with OpenCL and all Advanced settings on.

Perhaps more information on your system setup may help us to determine what might be the issue?

[heathera66554868]

Thanks for the video showing your method.  I agree, when you flatten to a layer, it does display correctly.  However, when I simply flatten a group (without merging it to the solid layer behind it), the falloff changes.  I don't think it's my system, since photoshop version 6.0 and cc 2015.5 both display the same before or after group flattening (not merging a group with a solid background).

I just tested it again in the newest cc 2017, and it's still preventing me from upgrading.  I'm a matte painter by trade, so painting in groups, then flattening them to take into compositing is the standard workflow.

[dzigakaiser]

Having the same problem here right now just when I wanted to merge and deliver my file 😕

Though, I have to say that I tried CS6, CC 2015.5 and the newest CC to no avail. The file was created in 2015.5 with the blend setting set to gamma 1.0. I have a lot of screen, haze and fog layers that cause issues now when I merge the groups. CS6 interprets the file the same way CC 2015.5 does. When I open it in the newest CC the layers go completely berzerk. All with the same color settings...

I spent the past 4 hours on trying to figure out some kind of conversion for the layers to create an emergency workaround but I'm about to give up. Is there a way to create a conversion via levels, curves? I tried several test setups adjusting the gamma curve for each channel to get as close to the original as possible but I can't figure it out. Once a conversion works for Group A and B, it doesn't work for C at all. I assume it all strongly depends on the actual pixel opacity value of the affected layer.

And I was actually believing I finally have a bomb proof matte painting workflow...always in for a surprise.

If someone comes up with an idea please let us know!

Take care,

Dziga

[dzigakaiser]

Okay, wow. I found a solution/workaround for my scenario. My struggle was with groups being set to "screen", though. In case anyone stumbles across the thread and has problems with screen or plus blend modes I'll still share my solution even though it won't apply to your scenario.

What I am curious about in your file: What happens if you switch the RGB blend option off and then merge the group and afterwards switch it back on?

Here my problem and my solution:

Problem:

Groups with screen/plus blend mode and containing transparent layers cannot be merged without breaking the RGB/opacity blending. (RGB blend with Gamma 1.0 is ACTIVE)

Solution:

1. Change the color settings back to default (disable the RGB blending checkbox).
2. Put a black solid into the bottom of each screen group.
3. When doing so nothing should change visually.
4. Merge each screen group.
5. Switch the RGB blending with gamma 1.0 back on and watch the scene transform.
6. You now have your look with merged groups!!!

Always put a merged reference layer into the file before starting the procedure to double check if the result is as it should be.

I hope this will help someone.

Cheers,

Dziga