Help with this effect

[limitliss]

I am reverse engineering a graphic design and want to know how to recreate this.

 

[Elli]

It looks like you're using Photoshop, so this is called a layer mask. Here's the tutorial:

Make your first layer mask

Learn basic layer mask essentials in Adobe Photoshop CC to hide parts of a layer and paint on layer masks.

helpx.adobe.com

 

[limitliss]

It looks like you're using Photoshop, so this is called a layer mask. Here's the tutorial:

Make your first layer mask

Learn basic layer mask essentials in Adobe Photoshop CC to hide parts of a layer and paint on layer masks.

helpx.adobe.com

great. but after I have the full hidden layer. how do I unhide a digaonal portion

 

[Elli]

but after I have the full hidden layer. how do I unhide a digaonal portion

Right, this is done with a layer mask. Watch the video to see how this is accomplished.