Can't get Select, Modify, Contract to work on a layer

[Carolyn246275190hci]

I'm editing a Photoshop graphic as i need to contract a layer. When I first did this graphic I had no problem selecting, modifying and contracting the layers. Now a few days later I have opened the file and when I select a layer (specifically the Cut Area) and select, modify, contract....the marching ants do contract but then I can't apply that contraction and it just reverts back to the original size.

I'm fairly new to Photoshop so I'm hoping it's just something straightforward that I'm not doing!

TIA

[c.pfaffenbichler]

Did you apply the Selection as a Layer Mask? 

[Carolyn246275190hci]

I don't think so, I'm using a template provided by a lasercutting company so the layers are preset, I then add my artwork to each layer.

[c.pfaffenbichler]

Then I am not sure what you mean. 

You have Layers, you have a Selection – what are you trying to do exactly with them now? 

[Carolyn246275190hci]

I select the layer and I want to contract the size slightly so I go to Modify, Contract ( 2 pixels) and hit OK. So the selection with the marching ants shows the contracted size but it doesn't actually fix it at that size...the original size remains under the marching ants and I can't get it to go to the same size as the marching ants. Something is stopping me from applying the edits but I can't work out what.

[c.pfaffenbichler]

What are you talking about? 

Selections and Layers are two separate things, so contracting the Selection has no bearing on the Layer. 

Unless you apply the Selection as a Layer Mask (Layer > Layer Mask > Reveal Selection). 

Edit: … or delete or use the Eraser Tool … but naturally a Layer Mask is pereferable because it does not cause loss of the Layer’s original data. 

[Carolyn246275190hci]

Ok, sounds like I'm doing the wrong method. In the screenshot I am going in to the layer named 'Cut Area' where there is a silhouette of a swallow..I wish to contract the size of the swallow by 2 pixels...is this possible?

[c.pfaffenbichler]

I have mentioned Layer Masks repeatedly.

Will you please apply the contracted Selection as a Layer Mask already? 

[D Fosse]

Wrong tool. "Select > modify > contract" is for contracting a selection - not the pixel content in it.

What you want is "edit > transform > scale". Specify in pixels or %, or just drag the handles.

[c.pfaffenbichler]

The Filters Maximum and Minimum will also affect a Layer’s transparent areas, but as they also affect the pixels’ colors I don’t think they are what the OP had in mind. 

[Carolyn246275190hci]

Ok, Thanks for your help.