Parenting only affects layer transformations (i.e. position, scale, rotation), not effects, masks, etc...
An adjustment layer can be used to affect all layers stacked beneath it in the timeline by applying effects to the adjustment layer.
The downside of this is that it will alter the appearance of any/all layers below it in the timeline indiscriminately.
Adjustment layers transfer any appiled effects to all layer which are below the Adjustment layer in the stacking order. It doesn't transfer transforms (position, scale, anchor point, etc), just effects. Layers which are stacked above the Adjustment layer are not affected.
On the other hand, parenting is all about transforms. A child layer inherits transforms from the parent layer in a relative way (ie, doesn't receive the same position values but reacts to changes in position for the parent layer).
I'll never grow tired of pointing out that After Effects Help has become an amazing resource recently. It will usually cover most of your question, and it will do so in a very clear way (plus, since it's community-based, you get to ask questions or post comments directly on aspects that may not be clear to you).
For example, this is the section on Adjustment layers.
And this is the section on parenting.
If you want to apply effects and set transform values for a range of layers, you can select them, pre-compose them and then adjust transforms and add effects to the Pre-Comp.
Thanks for the responses but I think both of you missed the question I was asking. Of course I know how adjustment layers work and my question was really is there a way to create a wokflow for effects and layers in the same way parenting can dictate transformations. The closest method I can see at the moment to achieve this is by precomposing layers, but this is quite clunky because you cannot detach and re-attach layers as quickly as you can with parenting.
I hope thats clearer,
Precomposing would be your best bet.
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One of the most efficent ways (but still not as transparent as parenting) is to link all common parameters (ie, all the parameters you will want to adjust at a time) to expressions controls effects in a single layer, and then link the common parameters to those expression control effects. Of course, this makes more sense if you're doing something more than just transferring parameter values (in which case, as Steve said, the best idea is to pre-compose), but maybe you want to animate them all with common values, but introduce randomness, an incremental step in values, etc.
and then link the common parameters to those expression control effects
Not to do this and this only, but... I suspect you'll want to get fancy with it all , so learning about expressions is a lof of fun and it's a door to one of the most powerful aspects to AE.
In this case, you just have to use the expression pick-whip to connect each parameter with a expression control that includes an equivalent parameter. In other words, if your effect parameter (say Blurriness) uses a slider, you want to connect it to a Slider expression control effect. If it uses degrees, you want to connect it to a dial expression control, etc. Actually, nothing prevents you from using non-matching parameters (slider to dial, etc), but it's just not a good idea to start with.
Of course, an introduction to expressions in well beyond the reach of a forum post, but you can take a look at the Using Expression Controls Effects page and the whole Expressions section in After Effects Help, while we're at it.
Dan Ebberts, a frequent poster in these forums who IMO is the top guru in all things related to expressions, has an amazing web site covering expressions and scripting for different expertise levels.
thanks a lot