Having a hard time following what you are wanting to accomplish. Could you maybe provide a screenshot and maybe an example or two of what you're wanting as a result?
want to take screenshots so we can see what you are doing and better understand the effect you want to create? showing steps helps
A blending mode just changes the way the layer with the brush stroke blends with the layer below (i.e. your jpeg layer). It does not make the layer below transparent.
It sounds like you need to add a layer mask to your jpeg layer and paint your brush stroke onto that. Where the mask is white the jpeg will show, where it is black it will become transparent.
If you want to apply the same effect to several layers - put them in a group and add a mask to the group
Thank you so much for responding. I'll include some screenshots of a couple of crude example of what I am aiming for. And that basically is providing an image to be printed onto a T-shirt and that has some creative transparent aging effects (grunge) that allows the T-shirt color show through the image. Hope that makes sense. My PSD image shows some test grunge showing transparency through blending on the "grunge" layer - but that layer and effect is fixed on top of the layer underneath. I can slide the underneath layer position around and the hopeful poke through layer above it remains fixed without penetrating the layer beneath. That probably makes no sense.....
The first U.S. flag above is a jpeg brought into Photoshop CC 2017. The second U.S. Flag shows transparency from my Layer Style > Layer Blending Mode - "layer 1" knockout to transparency. But it is fixed above layer "US Flag 2". When I add a layer below that to check it with a solid color just to see the color come through - it does not. The grunge in the top 3 t-shirt examples show the "background" or t-shirt color coming through. Hope this makes sense....... Thank you for any and all help and suggestions
now that I can see what you are doing :
When you put the T shirt layer at the bottom to check, just make it a background layer. The knockout will stop there
Wow davescm - That did the trick! You have saved me. Thank you all and if you have other suggestions I'm all ears - now I don't have to jump into illustrator - quite yet........... Thank you to WILDCAT54 and JonathanArias if you guys have more ideas and hints or suggestions let me know!
Thanks very very much!!!