Difficulty with modify > contract on a saved selection

[tracys3963529]

I selected part of a photo (a tree) then copied it to a new bank layer (Cmd+C then Cmd+J) and then saved it as a psb file. When I opened the file later I wanted to contract the tree by 10 pixels but can't find a way to do this and save the result. I select the tree then modify > contract and can see the marching ants have moved in as expected - but what command or sequence can I use to then save this contracted (smaller) image? Everything I've tried so far just reverts the image to the original. Thanks in advance and hope if there is an answer I understand it! 

[melissapiccone]

You can just jump your new selection to a new layer - after you contract, cmd + j and you will have it in a layer. 

[tracys3963529]

Thank you very much for taking the time to reply.  This did seem to me like it would be the perfect solution but when I've tried it I get a new copy on a new layer that's exactly the same size as the first (i.e. not contracted). Strange - but appreciate I may still be doing something wrong!

[melissapiccone]

That doesn't make any sense, it should work. Are you sure you are turing off the layer below - the original layer so you can see the new one?

Try selecting the inverse. If you have the tree selected, and you contract the selection, select the inverse (cmd + shift + i) and then delete - you should be left with the inside of the tree.  

I used generate to make a tree. I used the object selection tool to select it. I contracted by 10 pixels and jumped the selection to a new layer - it's smaller (the one on the left). 

[Myra Ferguson]

Select > Modify > Contract... modifies the border of the selection by the value that you enter--in this case, 10 pixels. If you'd like to hide the portion that is no longer selected, then you can use a layer mask. Click on the 3rd icon from the left at the bottom of the Layers panel to add the layer mask. You can also go to Layer > Layer Mask > Reveal Selection...

Hiding pixels with a layer mask is considered a non-destructive approach. It allows you to go back and add content from the original image by editing the layer mask. If you apply white, such as with a brush, on the layer mask, then the white will restore any of the hidden pixels.

[tracys3963529]

Thanks so mcuh for the reply. I generally want to use my selection in composites so haven't used layers masks on them much but this is option I'll play around with more. It's all learning at the end of the day.

[Myra Ferguson]

Here more information about using layer masks, in case that helps:

https://helpx.adobe.com/photoshop/using/masking-layers.html