luminosity blend mode producing color casts from layers

[SpartaPhoto]

I have read many threads on this topic but cannot find what I am looking for. For example, in my architecture work I want to simply use layers in luminosity mode and brush in the luminance (brightness) of a window layer. This is quite common in PS and ON 1 Photo Raw.  However, when using this work flow on Affinity 1.7.3 the luminance (brightness) of the layer I am blending in actually produces the color of the layer and not the brightness. So for example if the window I am blending in has some yellow color cast the yellow appears in the blended layer instead of just a brightness. This is true for shadows that are blended in also. Can anyone tell me if I need to use a different blend mode to achieve brightness or shadows without a color cast or is there something additional needed in the luminosity blend mode to achieve brightness/shadows without a color cast.

Edited November 4, 2019 by SpartaPhoto

[Chris B]

Hey SpartaPhoto,

Could you provide the afphoto file and the exact steps you're doing?

I'm only guessing at what you're doing at the moment and that won't be sufficient enough to reproduce and log this with the developers. 

If you can provide a screenshot of your results in Photoshop too that would be brilliant! Thanks! 

[SpartaPhoto]

Hello,

Attached are files from Affinity and ON1 Photo Raw (Note that PS gives same results as ON1). The first 2 images on the first row ( layer 1 intro, layer 2 intro) are layers that I will be using to blend with a brush in Luminosity mode (lum layer mask photo). After brushing the section on the right hand side of the photo with the arch you can see that the color of the light comes through in the door way and not simply the luminance i.e. brightness  (see "brushed layer w color cast photo") . This is not what I expect as I only want the brightness to come through.

The next 4 images with the On1 name in the file represent the same steps taken but this time using the ON1 Photo Raw program. I have tested this in PS and it works the same as ON1 which is the correct result.  The final image "On1 brushed layer w NO color cast" shows the result after I have brushed in over the arch doorway in luminosity mode. The arch way is simply lightened without a color cast.

Luminosity blend mode via a brush is a common practice for me in my architecture work and unless Affinity defines luminosity different from PS then I believe this is a bug. Please advise.

Thanks

[SpartaPhoto]

Hello can someone from Affinity please respond to this issue!

[Chris B]

Hi SpartaPhoto,

Apologies for not getting back sooner.

I really need the original image or the .afphoto file so I can attempt to reproduce this. The screenshots are helpful because I can see a clear difference but in order to pass this over as a bug report, the source file will be most helpful. Thank you so much  

[SpartaPhoto]

Thank you for your attention to this. I have attached the .afphoto versions of the files. Please advise.

layer-1.afphoto

layer-2.afphoto

[James Ritson]

Hey @SpartaPhoto, from my understanding you want to do the following:

1. Blend the lighter doorway area from layer-1 into the composite of layer-2
2. Blend through only the luminance and not the colour information

If this is correct, there are a couple of pointers:

• Setting the blend mode on the mask (e.g. Luminosity) will not do anything
• It looks like you have the layers the other way round in Affinity Photo when compared to your ON1 Photo Raw screen grabs (and presumably Photoshop as well?)

To replicate the result you're getting in ON1 Photo Raw, just do the following:

• Put layer-1 above layer-2
• Set layer-1's Blend Mode to Luminosity (the pixel layer, not the mask)
• Add a layer mask and invert it (Layer>Invert)
• Use the Paint Brush Tool to paint in over the doorway

I've attached a quick video to demonstrate (see attached at bottom of post). Hopefully this is what you're trying to achieve? Note there is still a little bit of orange colour bleed in the top left of the doorway but this is consistent with the result from ON1 Photo Raw. You could always add a quick HSL adjustment layer, desaturate, invert (Layer>Invert again) and paint back in over that area if it concerns you.

Hope that helps!

 

[SpartaPhoto]

Thank you for this explanation. Upon reviewing my steps the main issue is that I added the luminosity mode on the mask and not the pixel layer. It is working as expected now. Thanks!