Layer Fill Opacity in Blend Options

[NotMyFault]

Can anybody explain the new (since V2) "fill opacity" setting in blend ranges?

Why does it make a difference for the special 8 blend modes?

-> layer blend range fill opacity (same as Layer FX fill opacity)

-> color panel fill color opacity

-> layer opacity

https://affinity.help/photo2/en-US.lproj/pages/Layers/layerBlendModes.html

'Special 8' blend modes and fill opacity

When adjusting blend opacity, some blend modes (listed below) work best by adjusting Fill Opacity, rather than the layer's Opacity. The Fill Opacity option is available from the Layers panel’s Blend Options option. Fill opacity is essential when using Hard Mix blending in particular.

fill opacity miracle.afphoto

[Murfee]

2 hours ago, NotMyFault said:

layer blend range fill opacity (same as Layer FX fill opacity)

 

Hi @NotMyFault, it is not the same as in Layer FX opacity, that is for layer content opacity, eg. Transparent text but with effects such as outer shadow

The fill opacity in the blend ranges panel is different in the way it blends, particularly for some of the special 8 blend modes, Hard Mix & Linear Light. Very useful for colour grading images.

Try adding a layer fill over an image, set the blend mode to either Linear Light or Hard Mix, then try the different opacity settings, Layer Opacity, Layer FX opacity and then Fill Opacity in the blend ranges panel

i can’t really explain it at the moment but I believe the Layer Fill Opacity in the blend ranges panel works on colour projection rather than normal opacity

 

[NotMyFault]

Thanks for reply.

Fill opacity is always in sync with layer FX, it is one setting.

I have read the help file telling of it’s use cases. I want to really understand how exactly it is working.

So if someone could provide the actual blend formula.

e.g. for blend mode add, it is 

r= a1*r1 + a2*r2

a=a2+(1-a1)*a2

and alpha is always the result  of multiplying all involved alpha values (pixel alpha, layer opacity, and normally fill opacity)

(Similar for green and blue)

For simplicity lets ignore gamma correction, and those blend modes working in HCL.

So please introduce f1 and f2 for fill opacity of the upper/lower layer.

One option fill opacity may get excluded at some stage of layer blending.

[Murfee]

13 minutes ago, NotMyFault said:

Fill opacity is always in sync with layer FX, it is one setting.

Not in my experience, they are separate, and work differently

There used to be some confusion with people thinking they were the same before the fill was added to the blend range panel

i have no idea what the blend formula is, and don’t need to know 😀 I know that I get some very nice results with colour grading using the fill in the blend ranges panel, set to about 10% and using Linear Light or Hard Mix

[Return]

1 hour ago, NotMyFault said:

Fill opacity is always in sync with layer FX, it is one setting.

Yes it is one setting for both the fx panel and the blendranges.

 

 

[lacerto]

It seems that blend mode fill opacity does not actually work at all for certain blend modes (e.g. Vivid) and color values, e.g. in the clip below where a blue ellipse on top is blended with an underlying rectangle with linear gradient from R255 G0 B255 to white (so the objects are sharing the blue channel all the way). There is no gradual change at all, but decreasing the fill opacity from 100 towards zero has the same "blend effect" right from 99% to 0%. In different conditions blend mode fill behaves less radically different compared with identical objects with reduced color and layer opacity but as for the assumed gradualness of fill opacity, the functionality simply just seems to be lost (= opacity is just 100% on or 100% off).

 

 

[lacerto]

I noticed that the blending effect can vary a lot when exporting to CMYK and that graduality of the fill opacity set in Blend Options can come back:

The document used above is RGB/8 and all color definitions are RGB based. The effect shown in the clip when exporting to CMYK would happen only when exporting to PDF, but not when exporting to CMYK JPG or TIFF. It is pretty much impossible to predict in what way the blend option fill opacity will differ from fill opacity set in the two alternative ways, so this is really just something experimental. But as the difference of effect is stated in documentation, the feature probably works "as designed".

[NotMyFault]

34 minutes ago, lacerto said:

It is pretty much impossible to predict in what way the blend option fill opacity will differ from fill opacity set in the two alternative ways, so this is really just something experimental. But as the difference of effect is stated in documentation, the feature probably works "as designed".

Exactly.

Another example of Affinity implementing a „random“ feature in good intentions but not giving required documentation how it is exactly implemented, and how exactly to use it. 
this crates a lot of avoidable tension as all users try to figure it out on their own. Or stumble by accident activating this feature and getting unexpected results.