|Just that we'll be going in "baby steps".|
Let's start out with "what are they?". They're containers. If you are familiar with Russian nesting dolls, they make a reasonable analogy. You can put one Smart Object inside another Smart Object.
In its simplest form it's a way to gain greater control over your use of Filters. To make a Layer into a Smart Object you have (at least) two methods open to you. One: go to Filters and click on "Convert for Smart Filters". The other way to get at Smart Objects is to right click in the Layer Box. You'll be presented with a dropdown. The fifth item down reads "Convert To Smart Object". Don't worry about the name, either one makes the Layer a Smart Object. The first just gives you a clue to one of the things a Smart Object can be used for. If you have a Layer that you'd like to use a Filter on, you can skip the Smart Object and go directly to Filter/whatever type/specific type and apply the Filter of your choice to the Layer. Problem is making any changes to the Filter settings once it's applied. If you apply a Filter without making the Layer into a Smart Object you get one shot. You use the Filter and move on. After you've moved on you are stuck with whatever settings you picked. If you convert the Layer to a Smart Object first and then apply a Filter (or several Filters) you'll see in the Layers Panel that the Layer you put the filter on now has an indent under it saying Smart Object. Another indent (under the first) will tell you which Filter has been applied. It might look like:
- Layer to be used
- Smart Object
- Bas Relief
There will be a visibility "eyeball" in front of each indent. You can turn off the entire Layer. Turn off all the Smart Filters, or turn off individual Filters. There's also a Mask associated with the Smart Filter. You can remove whatever was applied to specific areas of the Layer. This will affect all the Filters. If you click on a particular Filter (let's say the "Fresco" Filter), the filter will reopen showing the currently used settings. The settings can be adjusted 'til your heart's content. You're no longer "stuck" with the settings you applied when you first thought to use the Filter. You can go back and forth all day.
One scenario might be that you've applied a filter and it looks great. You go on working on the image and adding additional Layers. At some point you realize the additional Layers have had an effect that makes the filter look a little "too something". Too much, too little, totally wrong, just really bad and you feel the need to change (or remove) the settings. By having previously converted the Layer to a Smart Object you have the ability to go back and make further adjustments.
That takes care of one aspect of Smart Objects. This post is getting a little wordy. We'll have to look into other functions of Smart Objects in the coming weeks. It'll probably be three or four "Wednesday Q&A sessions to fully resolve what can be done with Smart Objects and how to control them. If you're interested in or upset by Smart Objects, come back for the next couple weeks and we'll get through them.