Help needed for the Blend If function in Layer Styles

[EdmondsTim]

Operating System

1. macOS 26 Tahoe

Hello all you Blend If experts out there!

Adobe says :
".... use the sliders to set the brightness range of the blended pixels—measured on a scale from 0 (black) to 255 (white). Drag the white slider to set the high value of the range. Drag the black slider to set the low value of the range."
https://helpx.adobe.com/photoshop/using/layer-opacity-blending.html

But, i have seen some use an adjustment layer, like Blur or an LUT, as the Current Layer. What are the tone values 0-255 for pixels in an LUT layer?

Thank You
Tim

 

[Johan Elzenga]

AFAIK, an adjustment layer is treated as a copy of the underlying layer(s) with the adjustment applied to that, so that is how Blend If can use this. You can also use the underlying layer for blending the adjustment layer, so that is another way how it is often used.

 

[johnbeardy]

But, i have seen some use an adjustment layer, like Blur or an LUT, as the Current Layer. What are the tone values 0-255 for pixels in an LUT layer?

The Color Lookup adjustment layer (which is what I think you mean) doesn't have its own pixel values but has varying effects on whatever values it's applied to.

Blend If's Current Layer slider targets cumulative values, the result from adding the Color Lookup adjustment layer on top of the layers below it.

 

[EdmondsTim]

Thanx John and Johan,
That makes some sense. I wish Adobe would explain it better!
John - You are correct, it was a Color Lookup adjustment layer using the 3DLUT File and picking a suitable file. I skipped a step and called it a LUT adj.

Thanx
Tim

 

[johnbeardy]

It's actually pretty difficult to explain unambiguously. But those Blend If sliders are important to understand (especially the Alt/Opt trick to split the slider control) and they can provide a big step forward in how you use layers.

 

[David Tillett]

Blend If can work in two modes - "This Layer" and "Underlying layer". The latter is the mode that is most common in standard photo processing. The adjustment with the Blend If settings is applied just to the tones in the of the underlying "image" matching the Blend If settings. ("image" is result of all the underlying layers). So in your example the LUT changes may only be being applied to highlights.

If you are familiar with Lightroom Masking think of the Blend If settings as being the same as a Luminance Range mask.

The "If This" mode uses the tones in the current layer to determine how the adjustment would be applied. I don't think I have ever used this mode but I believe that it would mostly be used in compositing. For example if adding a pixel layer of object on white background the latter could be made transparent by using Blend If to filter out the highlights/white.

This video may help explain it better https://www.youtube.com/watch?v=xfvqyAE0VkMhttps://www.youtube.com/watch?v=xfvqyAE0VkM

 

[EdmondsTim]

Blend If can work in two modes - "This Layer" and "Underlying layer". The latter is the mode that is most common in standard photo processing. The adjustment with the Blend If settings is applied just to the tones in the of the underlying "image" matching the Blend If settings. ("image" is result of all the underlying layers). So in your example the LUT changes may only be being applied to highlights.

If you are familiar with Lightroom Masking think of the Blend If settings as being the same as a Luminance Range mask.

The "If This" mode uses the tones in the current layer to determine how the adjustment would be applied. I don't think I have ever used this mode but I believe that it would mostly be used in compositing. For example if adding a pixel layer of object on white background the latter could be made transparent by using Blend If to filter out the highlights/white.

This video may help explain it better https://www.youtube.com/watch?v=xfvqyAE0VkMhttps://www.youtube.com/watch?v=xfvqyAE0VkM

Thanx David, Wow! f64 Academy really really likes BlendIF. I will have to look into his stuff.
I know LR Masking, but i am better with PS Masking. A Luminance Range mask might be equivalent, but wouldn't that produce a static Mask that doesn't change with edits of the colors or tones?
It is so confusing and Adobe is not helping since they don't fully define the function. They don't even bother to check for complete sentences. So, users make up their own explanations. Such as the lower layer pixels are 'pushed up to the top'. Yuck!!! What a mushy explanation, i.e. imprecise! BlendIF does one thing and one thing only, and that is change the transparency or opaque-ness of the Current Layer. It leaves the Underlying Layers unchanged, albeit they may be Masked by the Current Layer. I don't think anyone truly understands all of it. MattK makes a humorous observation. He says the Underlying Layers sliders should be called the Hide If sliders. Jesus Ramirez is great at applying it, the best i have seen.

Also, don't take my example of a Color Lookup adj layer too specifically. I was only thinking of any Current Layer that doesn't have pixels with inherent tones. I could have used a Grain Adj Layer. What is the tone value of the middle pixel of that layer? John explained that it is not the tone of that layer in isolation, rather the tone that results from applying the Adj. to the lower layers, or Target layer if a Clipping Mask is employed (another confusing nomenclature from Adobe).

 

[Conrad Chavez]

Wow! f64 Academy really really likes BlendIF. I will have to look into his stuff.

Yes, you should look into his stuff. f64 Academy (Blake Rudis) understands color theory more deeply than most other YouTubers (his background includes fine art painting), so his videos about using Camera Raw/Lightroom and Photoshop features are often more practical and insightful than what’s typically out there.

 

[David Tillett]

Tim, your comment "change the transparency or opaque-ness of the Current Layer" really describes the operation of Blend If. The complexity comes from whether the change is based on the values of the current layer or the underlying layers before the adjustment is applied. If you use it in "Underlying Layer" mode then its practical impact is no different from applying a pixel based luminosity mask to the adjustment before making changes to the adjustement.

In "Underlying Layer" mode the changes made by the layer with Blend If settings have no impact on the "transparency" of that layer, only the values in the current state of the image before adding the new adjustment.

I use Tony Kuyper's TK9 masking plugin (disclosure, I am also one of the beta testers of new versions). This includes functions for making use of Blend If simpler, much like the F64 Blend If panel. One of the options is to display a colour overlay of the areas of an image that are impacted by Blend If settings. I have just done a test of creating a curves layer with some Blend If settings. If I display the colour overlay and then play around with the curve the overlay does not change. If I add another curves layer with its own Blend If settings and display the colour overlay and then play around with the original curve then the overlay does change, but again not if I change the new curve.

Using a plugin to manipulate Blend If settings does make them much more accessible. The ones I have seen often allow a quick way to, for example, take adjustment out of highlight or shadows with a single button click.

Dave Kelly in his "Joy of Editing" channel covers use of TK9 in a regular TK9 Friday feature. Here is a link to one from a while back that covered using the TK9 Edit Blend If function, https://www.youtube.com/watch?v=RsKXnndJQBI&list=PLRE7yCl-SQfSmoUZ1FhC5i-KJcsPV-bcU&index=2, there was a second part at https://www.youtube.com/watch?v=nmK6gGv6-Jo&list=PLRE7yCl-SQfSmoUZ1FhC5i-KJcsPV-bcU&index=3

There are two main advantages in using Blend If rather than pixel mask - it is dynamic so if you go back and change a layer lower in the stack then the "transparency" of the Blend If "mask" will change accordingly, also because Blend If settings are stored in a layer's metadata they don't take up any extra space unlike a pixel mask.

You are right that my example of a Lightroom luminance range mask is static unlike Blend If. I gave it to try and illustrate that the "mask" is created on the current state of the image. If you create a luminance range mask and display the luminance map then make changes to the exposure settings you will see that the luminance range does not change in line with the updated image.

 

[EdmondsTim]

Tim, your comment "change the transparency or opaque-ness of the Current Layer" really describes the operation of Blend If. The complexity comes from whether the change is based on the values of the current layer or the underlying layers before the adjustment is applied. If you use it in "Underlying Layer" mode then its practical impact is no different from applying a pixel based luminosity mask to the adjustment before making changes to the adjustement.

In "Underlying Layer" mode the changes made by the layer with Blend If settings have no impact on the "transparency" of that layer, only the values in the current state of the image before adding the new adjustment.

I use Tony Kuyper's TK9 masking plugin (disclosure, I am also one of the beta testers of new versions). This includes functions for making use of Blend If simpler, much like the F64 Blend If panel. One of the options is to display a colour overlay of the areas of an image that are impacted by Blend If settings. I have just done a test of creating a curves layer with some Blend If settings. If I display the colour overlay and then play around with the curve the overlay does not change. If I add another curves layer with its own Blend If settings and display the colour overlay and then play around with the original curve then the overlay does change, but again not if I change the new curve.

Using a plugin to manipulate Blend If settings does make them much more accessible. The ones I have seen often allow a quick way to, for example, take adjustment out of highlight or shadows with a single button click.

Dave Kelly in his "Joy of Editing" channel covers use of TK9 in a regular TK9 Friday feature. Here is a link to one from a while back that covered using the TK9 Edit Blend If function, https://www.youtube.com/watch?v=RsKXnndJQBI&list=PLRE7yCl-SQfSmoUZ1FhC5i-KJcsPV-bcU&index=2, there was a second part at https://www.youtube.com/watch?v=nmK6gGv6-Jo&list=PLRE7yCl-SQfSmoUZ1FhC5i-KJcsPV-bcU&index=3

There are two main advantages in using Blend If rather than pixel mask - it is dynamic so if you go back and change a layer lower in the stack then the "transparency" of the Blend If "mask" will change accordingly, also because Blend If settings are stored in a layer's metadata they don't take up any extra space unlike a pixel mask.

You are right that my example of a Lightroom luminance range mask is static unlike Blend If. I gave it to try and illustrate that the "mask" is created on the current state of the image. If you create a luminance range mask and display the luminance map then make changes to the exposure settings you will see that the luminance range does not change in line with the updated image.

Thanx David. You comments give me a lot to think about. I am not sure i agree with the two modes approach. The sliders for each layer can be used in singly or in combination. I will have to play with it some more.

 

[EdmondsTim]

Yes, you should look into his stuff. f64 Academy (Blake Rudis) understands color theory more deeply than most other YouTubers (his background includes fine art painting), so his videos about using Camera Raw/Lightroom and Photoshop features are often more practical and insightful than what’s typically out there.

I like Blake's presentations. I replay several times his presentations from the Photoshop Virtual summits. Jesus also has some valuable insights. Two things that he has mentioned: BlendIf does not use HSL color mode, it uses HSB; which is apparently an attempt to better model how colors are perceived. Which explains some wackiness i have seen with BlendIf when using dark blue colors. Second, he will swap the sliders left-for-right and so the tones OUTSIDE of the sliders are chosen instead of those between the sliders. Again, more items that Adobe doesn't explain.

 

[EdmondsTim]

In "Underlying Layer" mode the changes made by the layer with Blend If settings have no impact on the "transparency" of that layer, only the values in the current state of the image before adding the new adjustment.

David, I am changing my mind on this. This Dual Mode view of BI (Blendif) doesn't work for me. There is no dual mode, only two ways of altering the transparency of the Current Layer. These two ways can be used singly or in combination in myriad ways. Does Adobe make any mention of this Dual Mode approach? I could be wrong; please let me know if i am.

Also, what does this mean? Perhaps you could be so good as to add a few more words to this comment: "only the values in the current state of the image before adding the new adjustment." I have found that using an Adjustment Layer as the Current Layer directly interacts with the Current Layer sliders just as John explained. example to follow.

 

[EdmondsTim]

I have just done a test of creating a curves layer with some Blend If settings. If I display the colour overlay and then play around with the curve the overlay does not change.

When i use the Current Layer sliders to cut off the brightest tones created by a Curves Adjustment Layer, i see the Adjustment removed from the Curves created bright tones in the image, just as Johnbeardy explained. The first image shows how I set the Curve to exaggerate the bright tones and used the Current Layer sliders to remove the effect above level 203. The second image shows the same Blend If settings but the Curves Adjustment is set to null. This shows that the effect of the Adjustment Layer is applied *before* the tone selection set by the Current Layer sliders is applied.
(credit - The original image comes from a class given by Tim Grey.)

 

[EdmondsTim]

I forgot to include the original before Current Layer sliders were used and the full Curves Layer effect is seen.

 

[David Tillett]

Tim, I don't claim to be a great Photoshop expert, I was just trying to pass on my understanding as a way to help answer your question.

As far as dual mode goes you are right the only thing that changes is the "masking" of the layer to which the Blend If settings are applied. While both sliders can be adjusted on the standard interface I can't really get my head around why you would want to use both at the same time, I have never seen a YouTube video in which any photographer has done this, perhaps in design or compositing situations there may be, but those are not areas I am interested in and have never explored.

So from my experience and understanding one either wants to exclude the adjustment based on its values, or on the values of the underlying layers. This is what I meant by Dual Mode, focussing on practical usage more than technical possibilities.

Blake Rudis's Blend If Photoshop plug in can switch between current layer and underlaying layer adjustment but if one switches between these then only the chosen slider is adjusted, the other is reset to full values. The other plugins that I am aware of that have simplified Blend If access, TK9 and Lumenzia, only make changes to underlying layer slider. If memory serves me correctly Lumenzia used to be able to manipulate both but somewhere along the lines the ability to manipulate the current layer slider was removed.

For my use of Photoshop to process standard images with no compositing or design elements like text I have never needed to use changes to current layer slider. And the YouTube channels I watch to help me with this type of processing rarely, if ever, make changes to current layer slider. Even though Blake's plugin has the functionality I don't recall ever seeing him use the current layer option.

I have played around with using Blend If on Bleach ByPass LUT as in your original question. I can see that changing current layer slider does have impact on its effect but I am not sure how I would use this as I got a more manageable result by using underlying layer slider to do things like restrict the application to the lighter tones in the image than by using current layer slider to only apply the lighter tones of the LUT.

My comments on changes to adjustment layer not having impact on Blend If settings referred to use of Underlying slider only. You are right that if current layer slider is modified then changes to the adjustment to which that setting is applied do change the impact of the Blend If settings.

 

[EdmondsTim]

David,
Thanx for your kind reply. I didn't know that the Current Layer was used so little. I am just learning about Blend-if. The more i dig into it and the other portions of the Layer Style menu, the more interesting they are. Blake Rudis' site and his add-ons look great. I signed up for f64 Elite.
Cheers
Tim

 

[David Tillett]

If you are a F64 Elite member then there is the Blend If course which includes the Blend If panel. Look in the course directory section if this link doesn't work https://f64elite.com/course/the-unrivaled-blend-if/ - login to F64 first then try link, not sure if site allows direct links.