7 Replies Latest reply on Jul 16, 2010 3:09 PM by JETalmage

    Stacking order vs. Layers?

    StanWelks Level 1

      I'm coming from working with layers in Photoshop and understanding how they work in there. Illustrator also has layers, though you are able to also change the stacking order of items on a given layer  by using the object > send to back or forward.

       

      1. Why would you want to send items to the front or back and not just use layers?

      2. When do you want to put an item on a new layer vs. just changing its stacking order?

       

      Thanks.

        • 1. Re: Stacking order vs. Layers?
          Larry G. Schneider Adobe Community Professional & MVP

          Normally layers are used to categorize items like text, images or graphics. If you had a raster layer and wanted to over-lay one image over another, then you could use the stacking order to get them in the right order. Using multiple layers can be used for the same purpose but is harder to keep orgainzed and less useful in tracking and selecting items.

          1 person found this helpful
          • 2. Re: Stacking order vs. Layers?
            StanWelks Level 1

            How is using multiple layers more difficulty to keep organized in tracking and selecting items? If I want to find a specific item, couldn't I just go to the layer designated for just that item and have it easily identifiable vs. clicking on a layer that has lots of different items and trying to isolate it from the other items?

             

            Thanks.

            • 3. Re: Stacking order vs. Layers?
              Jacob Bugge MVP & Adobe Community Professional

              Stan,

               

              To continue,

               

              1) Generally layers may be used to hold connected artwork, and you can easily turn visibility on/off, lock/hide, and apply transparency, effects, and many other things, to the whole layer.

               

              You can expand/collapse the contents of layers.

               

              If you wish to work with different versions of the artwork, you may (repeatedly) Duplicate Layer and make changes, and when done you may easily delete the layer(s) no longer wanted.

               

              If you Group artwork on different layers, everything is moved to the topmost layer.

               

              Those were just a few more reasons for having more objects than layers.

               

              2) When you wish to separate it from the artwork on the existing layer(s).

              1 person found this helpful
              • 4. Re: Stacking order vs. Layers?
                Larry G. Schneider Adobe Community Professional & MVP

                Depends on how much monitor area you have to display the Layers panel.

                • 5. Re: Stacking order vs. Layers?
                  StanWelks Level 1

                  Jacob,

                   

                  Just to clarify:

                   

                  1.) are you suggesting it is better to use layers for each item or not to?

                   

                  2.) I am not sure what you meant by:

                  "Those were just a few more reasons for having more objects than layers."

                   

                  and

                   

                  "When you wish to separate it from the artwork on the existing layer(s)."

                   

                  Thanks!

                  • 6. Re: Stacking order vs. Layers?
                    Jacob Bugge MVP & Adobe Community Professional

                    Stan,

                     

                    1.) are you suggesting it is better to use layers for each item or not to? Not to.

                     

                     

                    2.) I am not sure what you meant by:

                     

                    "Those were just a few more reasons for having more objects than layers."

                    That was the end of 1), suggesting to put multiple objects on the same layer.

                     

                    and

                     

                    "When you wish to separate it from the artwork on the existing layer(s)."

                    That was my answer to 2), when to put objects on on a new layer instead of continuing on the same layer.

                    • 7. Re: Stacking order vs. Layers?
                      JETalmage Level 6

                      Stan,

                       

                      The point you are missing is a conceptual problem common among many users who have some experience with Photoshop (or other raster image program), but next to none with programs like Illustrator (drawing programs) or InDesign (page assembly programs).

                       

                      The key difference is this: Fundamentally, a Photoshop file is, ultimately, one single raster image. An Illustrator (InD, CorelDraw, FreeHand, Canvas, Flash, Firworks, etc., etc.) file is a collection of individual objects.

                       

                      In object-based programs, all the objects are located somewhere in one big Z-stacking order. Think of Layers in these kinds of programs as just one heirarchal "level" of "grouping" contiguous objects within the stack. There are several other such organizational "levels". For example:

                       

                      • AnchorPoints exist in the one big Z stacking order. Sets of contiguous anchorPoints are "grouped" (connected) into paths.
                      • Sets of contiguous paths are sometimes "grouped" (combined) into compound paths.
                      • Sets of contiguous objects—including paths and/or text objects and/or raster images (each with its own color model, color depth, rotation, scale, DPI)—can be "grouped" into Groups.
                      • Sets of contiguous objects can be "grouped" into (reside on) Layers.

                       

                      Groups can be nested. You can have Groups inside other Groups.

                      Layers can be nested. You can have SubLayers inside other Layers.

                      In Illustrator and some other vector drawing programs, the Layers palette does not just list Layers. It lists every object on each Layer.

                       

                      All this organizational scheme is useful and important because of that one fundamental difference: These are object based programs. Now compare this to Photoshop. Yes, a Photoshop document can have Layers. But what is a Photoshop Layer really? It's just another raster image of the same color mode, same color depth, and same pixel count as the Layer(s) underneath or above it. The color values of corresponding pixels in any of the channels of each Layer can be mathematically combined to result in the color you see in that pixel location on your monitor and in the final result. But you don't have a stack of independent raster images. Think about it: In Photoshop, you don't have a 100 PPI CMYK image in Layer 1 while you have a 300 PPI RGB image in Layer 2.

                       

                      But in an object-based program, you can have a stack of any number of raster images, and each one can be scaled independently without loosing any of its pixels. In other words, the pixels in individual raster images on the page can be different sizes from the pixels in other raster images on the same page. Then you can throw live text objects and paths into the mix, as well.

                       

                      So more elaborate and flexible ways to organize objects is critically important in these kinds of programs. Example:

                       

                      • You set up a Layer to contain the background raster images of a magazine ad. There are several images, and they are independently scaled and positioned, sometimes overlapping. They need to be sorted in Z-order within that Layer. The Layer enables that particular set of objects (raster images) to be treated as if they were one object.
                      • In the same ad, you set up a Layer to contain the body text.
                      • In the same ad, you set up a Layer to contain the photo captions.
                      • In the same ad, you set up a Layer to contain an elaborate vector illustration.
                      • Within that vector illustration are hundreds of individual objects. Those are organized into subLayers and/or Groups. But the parent Illustration Layer lets you turn off visiblilty or lock the whole Illustration.

                       

                      And so on. So there are counless reasons "why you would want to send items to front or back" or change the stacking order of objects within a specific Layer—because there are countless situations in which different organizational levels make sense in terms of working efficiency. There is no single one-size-fits-all answer to your question. But trust me, all the Z-stack organizational "levels" are important. And they are all standard fare in object-based vector illustration and page layout programs.

                       

                      JET