Rasterizing group with color dodge layer gives unexpected result

[MagicOfIllustration]

Version used: 1.7.3.481
I Tried to rasterize a group that contained a layer that is set to color dodge.
I Expected the group to be rasterized exactly like it was when it was still a group, however the end result looks different from when it was grouped.
The result can also be seen if you merge down the color dodge layer.

(Example file in the attachment)
Click on the group and select rasterize for the issue I'm talking about.

color dodge example.afphoto

[Greyfox]

9 hours ago, MagicOfIllustration said:

Expected the group to be rasterized exactly like it was when it was still a group, however the end result looks different from when it was grouped.

If the blend mode of the group is set to Normal instead of Passthrough then rastorising the group appears to work as expected.

Alternatively, if you leave the group blend mode as Passthrough, and remove the black fill layer that is below the group, then rastorising the group also appears to work as expected.

My understanding of Passthrough blend mode is that It allows things applied to layers within the group, to affect layers below the Group in the layers panel,.

I'm no expert in the use of blend modes, so perhaps someone else can give a more technical answer as to why this is desirable.

 

 

[MagicOfIllustration]

Yes I've been playing with it a bit more and I think this is might just be a technical limitation. I Think it is because I'm using a black background and when rasterizing the app uses white for premultiplied alpha calculations. I Tried a different approach to get the result that I want but I run into issues with that as well.

To try to get a nice transparent rasterized layer from the group with the correct colors I tried this.
- Put the black background into the group, this way it has a solid black background to rasterize.
- But I needed the transparency so I added a mask on the group. This looked good, however when I rasterized the group the end result has a different transparency compared to the mask of my group. 

[Greyfox]

8 minutes ago, MagicOfIllustration said:

This looked good, however when I rasterized the group the end result has a different transparency compared to the mask of my group. 

Why not just set the blend mode for the group to Normal?

[MagicOfIllustration]

7 minutes ago, Greyfox said:

Why not just set the blend mode for the group to Normal?

Because it gives white parts in the result image.
I Will show you what happens in the image I'm working on:

With passtrough (the way I want the clouds to look like)

With group set to normal:

For the project I'm working on I would like to export the black background with the stars and the purple clouds in two separate images. But I can not do this because I can not export the clouds the way I want to.

[Greyfox]

8 hours ago, MagicOfIllustration said:

Because it gives white parts in the result image.

OK. Unfortunately then at this stage I don't have any other suggestions I can offer, Hopefully someone else can provide some ideas.  

[Gabe]

Hi both,

There's nothing wrong with the way it works. If you hide the black layer and rasterize, there is no difference in the result. 

You cannot really have that result in 2 images because you're using different blend modes. If you need to composit them later, why don't you just export the 3 layers separately and set the blend modes there? 

[MagicOfIllustration]

Just now, Gabe said:

Hi both,

There's nothing wrong with the way it works. If you hide the black layer and rasterize, there is no difference in the result. 

You cannot really have that result in 2 images because you're using different blend modes. If you need to composit them later, why don't you just export the 3 layers separately and set the blend modes there? 

I Can export them separately but it's being used in a software product, rendering a color dodge blend mode takes much more processing power than normal blending. Therefor I would like to avoid using that in real time. I Think I will have to rethink how I'm creating this image and maybe I will need to recreate the effect in a different way.
That being said. I Don't understand why if I put a solid black background layer in my group and a mask on the group. That the resulting image is difference when I rasterize the group.

[Gabe]

You cannot really bake blend modes into the layers as they are dependent on the layer beneath. 

15 hours ago, MagicOfIllustration said:

That being said. I Don't understand why if I put a solid black background layer in my group and a mask on the group. That the resulting image is difference when I rasterize the group.

Can you attach an example please?