Adjustment layers and groups in Photoshop

This has been a bit of a revelation for me, some of you might have known about this all along, but this option has eluded my knowledge for ages...yes, you can use adjustment layer in Photoshop for groups, not just for individual layers or the whole document.

I have been complaining, with my work colleagues, about the lack of ability to confine adjustment layer effects to a group, so that you could effect multiple layers with one adjustment layer and yet not the whole document underneath the adjustment layer (nor having to copy an adjustment layer multiple times and the connect them individually to desired layers). You can connect a adjustment layer to a single layer by having the adjustment layer above the desired layer and then alt+LMB inbetween the two layers in the layers tab. If you have multiple layers under a group and then add an adjustment layer above the group and try the same trick, nothing will happen.

Just placing the adjustment layer inside the group (on the top) will give you exactly the same result as it being outside on the top of the group and it will effect the layer underneath the group as well. This is because groups' layer blending mode is by default "Pass Through" which means that the group has no effect on the visual style of the document, but it is only a organizational element in the layers tab. If you switch the blending mode of the group to "normal" instead of "Pass Through" the group effectively becomes a single layer with a blending option of "normal"(essentially the same visual effect as merging the group and leaving on "normal" blending mode). What this means is that the elements inside the group get composite together first and only afterwards layered on top of the rest of the document and this is the way to confine adjustment layers to a group.

So, by putting an adjustment layer inside a group and switching the groups blending mode from "Pass Through" to "Normal" you can have the adjustment layer to effect only layers underneath it inside the group and not the layers outside the group, even if they are underneath the group.

This helps to keep the document clean and easy to manage, you no longer have to duplicate multiple adjustment layers in order to keep the workflow undestuctive.