create a new layer on top of your image, fill it with white and set it to the difference blend mode, then that's the same as image, adjustments, invert.
Actually?... no, it's ALMOST the same but not completely.
Using the "Invert" Adj. Layer allows you to use any of the blend modes to further create a special visual blending effect. This "extends" the effect of only using the Difference blend mode itself. Try it, you'll understand what i mean. Add that Adj. layer and then change modes.
If i'm understanding your dilema right, then there IS a workable solution to your question... "painting the effects on".
Simply put... dupe your source image, apply the desired filter effect to the dupe, then add a layer mask filled with black, and last, grab an appropriately sized brush (
soft most likely). and "paint" the effect over the original source image by painting white onto the layer mask in the areas you wish to 'effect'.
Simple really. :B
You can also change the blend mode of the 'painted' effects layer to create other visual effects.
Slightly higher doc size in the end if saved unflattened, but worth it considering there's no other alternative. [slick]
Not a brilliant example here, but i'm sure you get the idea. [honesty]