Hello.
Is there a way to do Frequency Separation without utilizing the Contrast Blend Modes Group?
Due to the nature of editing I am doing using standard Frequency Separation techniques leads to unpleasant ghosting/ringing/halo type artifacts that build up with every step.

Is it possible to isolate the high frequency and the low frequency details on separate layers and have them stacked in a regular pass-through stacking modes, such as normal or the difference group?
I have attempted to do such extractions using the difference blend modes group "isolating" the details and placing them on top of an image that had the details subtracted away. However, the detail selections and the tone selections always seem to be partial in nature so the image looses it's full opacity and one can "see thought the image" down to the background layer. Turning off the background layer reveals the partial nature of the image and both details and tones look "ghostly". Repeating the process builds up the opacity but is cumbersome.

Any advice?
Thank you.
E

I have never seen those kinds of effects. Providing more detail of your exact steps when creating the separation, and how you are working on each layer would be helpful. I have seen odd results when I didn't make suret that my tool sample setting was for current layer and not current and below or all layers. Based on my understanding on how the math works I don't believe you can use any blend mode other than linear light for the high frequency layer

Why do you get halos? Could explain a bit more?

It is difficult to understand what exactly you are doing and what you are after. If you separate frequencies correctly there should be no change whatsoever after separation. So halos etc can be a result of doing something wrong during or after separation. Maybe if you explain better and more visually we could help.

Why not just do it the normal way?

Clarification to the many replies to try to help me.

1. I am after having the details on a NORMAL blend mode layer. I do not want my details top layer to be in any of the contrast modes like Linear light. That is the goal I am after.

2. I set up my frequency separation the usual way with Apply Image routine, as a back up I have used High Pass method,  works the same. There are NO artifacts or halos or anything with my setup, it's the standard way of doing things.

3. The artifacts/halos/ringing comes AFTER I start my work. Doing any sort of "tune up" to the top details layer leads to the artifacts. It is not from clone stamp. It is from putting layer adjustments and other effects on the top layer. The adjustment interacts first with the top layer and then gets Linear Light blended down and that is what creates artifacts. You can try it yourself, just throw any soft of adjustment on the top layer. It will also shift colors, contrast, brightness, etc etc in completely unpredictable ways. (However, sometimes it produces magnificent effects if I could only control them better and isolate the effect to the details, not everything else it interacts with). One of the effects that I have produced accidentally which is almost "production ready" is the image appears fully sharp yet like it is behind frosted glass or ice, very cool. But the colors/tones and brightnesses are horrendous and completely unnatural. The other effect has been more of a 3D look "emerging out of fog" figure. Also, free hand drawing on the detail layer is very interesting but very unpredictable.

4. If I could only have the details sitting on the top layer in normal mode, then I would make my adjustments and the way they appear on the top layer in normal mode would be the way they are and the effect would be the way it is. Having the details appear they way I want them to be is great, except now they are still in Linear light and things "go left" from there as the new "magical detail" layer is blended with the bottom layer and the results are ghastly.

5. Extracting details with the difference blend mode, selecting them, moving them onto the top layer and working that way leads to only partial weak selection of both details and tones. It does work but since the selection is partial you can see through the image to the background layer so all my effects are very very weak and don't add up to a whole lot.

6. The final goal is like a construction blue print on a tracing paper. When the whole blue print is looked at you see all the details and objects. But you can pull write/draw on each layer individually and it just shows through, it doesn't interact with the layers above or below. I want to be able to change the top detail layer and not have it interact in any way with the lower layer.

I hope that helps.
I will try to produce some results and upload here but the above should be a reasonable technical explanation of what the current situation is and what I am after.

Thank you everyone

If I've read your description right, you might want to try the following:

1. Make a dopy of your High Frequency layer.
2. Clip the copy layer to the original.
3. Set blending mode of the copy to Normal.

You can now work on the copy just as you would have the original, but it's in Normal blend mode. You can duplicate and clip as many times as you need.

It seems step 3 is the one that is causing you trouble. You are not supposed to "tune up" any of the 2 layers after separating them. They work in sync and if you apply any adjustment to any them that sync will no longer be and therefore you can see all kinds of weird effects which will be difficult to control (if possible at all). So I would recommend that you stick with cloning on the high frequency layer without other operations. If you need further adjustments - do them in additional layers, not on the separation.

If you want to have only the difference between what you have done in the FS and the underlying layers, you can do this:

1. Merge high and low frequency into a new layer
2. Put it in difference mode.
3. Ctrl+shift+click each RGB channel
4. Create a layer mask with this selection
5. Apply a steep curve to that mask, so that black and white are clearly defined
6. Ctrl+click to select the mask and grow the selection e.g. 10px
7. Fill that with white
8. Deselect and blur with 10px
9. Apply the mask
10. Set blend mode to normal

This will give you a layer in normal mode which will contain only the actual work you have done on the separation (plus 10-20px around the areas for safety). It will also make your file smaller and less memory consuming, so you can work faster with next layers. You can use this technique to isolate layer difference for any type of raster layer, not only for FS.