The Difference Between Duplicate Layer and New Smart Object via Copy
Smart object layers are one of the most useful features and building blocks of Photoshop. I have already covered what are smart object layers and what is the difference between linked and embedded smart objects. In this post, I will cover the difference between two separate commands: Duplicate Layer and New Smart Object via Copy. At first look there isn't any difference, you will get what you expect: duplicated smart object layer with exactly same content. The difference is actually big and every Photoshop user should know about it.
What is actual (big) differenceThe actual or big difference is that duplicated smart object layer using Duplicate Layer command will result with cloned and linked smart object layer. Duplicated smart object layer using New Smart Object via Copy command is only duplicated or replicated smart object layer without any connection between parent and child. Let me give you some more light on the subject with more detailed explanation.
Duplicate Layer commandThis command is available from Layer > Duplicate Layer menu, through keyboard shortcut (Ctrl/Cmd + J) and also appears in right click (contextual menu) when you are using right click on smart object layer in the Layers panel.
Resulting smart object layer after using Duplicate Layer command is identical with a parent. It is also linked to parent's content what means that any change on any of layers, either parent or child, will automatically reflect on both layers. This is true for actual content on the layer, not for filters, layer effects, and transformations. Changing effect, filter or transformation applied to one layer will not automatically reflect another, either parent or child.
New Smart Object via Copy commandThis command is available from Layer > Smart Objects > New Smart Object via Copy and from the context menu on right click on smart object layer in the Layers panel. The result of this command is exactly same layer as a parent which is used as a source with one big difference in comparison with Duplicate Layer command: the content of parent and child smart object layer is not connected in any way. Changing content of parent smart object layer will not affect the content of child smart object layer and vice versa.
The remaining part is that changing filters, layer effects, and transformation of parent smart object layer will not affect child smart object layer and vice versa.
Product used in this tutorial:
Adobe Photoshop CC 2017
Work with Smart Objects