5 Replies Latest reply on Sep 9, 2013 4:40 PM by JJMack

    Background layer default opening vanishing

    nico37500 Level 1

      Hi, when you open, let's say a PNG file, it creates a default locked  Background layer, fine, now edit it, turn it into Layer 0 for example,  and save, again as PNG, ...the next time you open that file, you'll get  your Layer 0 and not a Background layer, I definitely need to get rid  off that behavior, I need that Background Layer to be there! PNG isn't a  PSD or TIFF, why is Photoshop saving Layer infos? and where? in the  PNG? in a Cache ? I tried a bit of things to retrieve that "Background  layer" when opening but PS CS5 still stores that info somewhere...

       

      What I want is to prevent Photoshop doing that. That is, the next  time I'm re-opening a file that is not supposed to have layers (like a  PSD or TIFF), it opens it with "Background Layer" ! and not Layer 0 if I  already opened it / edited / saved in Photoshop.

        • 1. Re: Background layer default opening vanishing
          JJMack Most Valuable Participant

          If you open a png and it  has a background layer  it means that the png file has no transparence for a Photoshop Background layer does not support transparency.   If you want your file to have a background layer why did you convert the background layer to a normal layer to layer 0 which can contain transparency.  A background layer is always at least partially locked because is does not support transparency so its transparency is locked its fully opaque.  You can edit a background layer paint on it, sharpen in, blur it etc you just can not add transparency to it. You converted the background layer to a normal layer. Why. Its your behavior that need to be corrected. Or save it as a Jpeg file not a png for jpeg does not support transparency like png does. However PNG supports 16bit color and jpeg only support 8bit color. You can also convert the bottom layer in a layered document your editing to a background layer if its not a background layer.

          • 2. Re: Background layer default opening vanishing
            nico37500 Level 1

            Try doing the following :

            1) open a JPG file (no transparency, right?). Background layer is there.

            2) save it as PNG

            3) open the PNG .. Background layer still there.

            4) double-click the bg layer, convert it to Layer 0, save as PNG... still no transparency, right?

            5) open the PNG .. Layer 0 ! no more Background Layer.. and still no transparency.

             

            Two things, either Photoshop save that info in the file, or in a cache. And that can be annoying. It's not about my behavior as I depend on files I'm provided and working with, and scripts I made. I can't have 2000 files with Layer 0 and 1200 files with Background layer just because Photoshop is acting weird. Ok I could make a script as a work around to open all files and convert all background layers to layer 0 but I find it's not the way it should be. And I'd rather understand why Photoshop does this and if there's a way to prevent it doing it. And my little example showed you it's not about transparency.

            • 3. Re: Background layer default opening vanishing
              JJMack Most Valuable Participant

              That is correct you converted the background layer to a normal layer in step 4 you no longer have a Photoshop Background you have a normal layer with the contents that was in the background layer without transparency. A normal layer may have transparency it does not have to have transparency. A normal layer can also be larger then the canvas size you can transform it larger then canvas to increase the size of objects over the canvas,   You can also convert Layer 0 to a background layer if its the bottom layer.  Any transparent empty areas will be filled with pixels, any  areas with transparency will be made opaque and any pixels out side the canvas area will be cropped off. Photoshop is not acting weird it is working as designed.  You saved a PNG document that did not have a background layer so Photoshop save the PNG file with a normal layer which may or may not contain transparency and transparent areas.  PNG format supports transparency and transparent area as does PSD and PSB file formats.  Photoshop is working correctly is just not working the way you would like it to.  If you want a background layer make one or do not convert the background layer to a normal layer. Your jpg file still has a background layer for the is the only kind of layer supported by jpeg file format is a single background layer.

               

              Scripts can handle documents with and without background layers they can use logic.  If you want a background layer always add this to your scripts before they save files.

              // Make sure bottom layer is a background layer

              var layers = activeDocument.layers;

              activeDocument.activeLayer = layers[layers.length-1]; // Target Bottom Layer

              activeDocument.activeLayer.isBackgroundLayer=1;    // Make it a background Layer

               

              If your manually editing if the bottom layer is not a background layer target it and use menu layer>New Background Layer from layer.

               

              If you just using actions and you converted the background layer before your save as png insert these  two steps Alt|OPT+, (shortcut for target bottom layer) second step

              menu Layer>New> Background From Layer

               

              The PNG will have no transparency or transparent areas.

              1 person found this helpful
              • 4. Re: Background layer default opening vanishing
                nico37500 Level 1

                Thanks for the script tip and detailed explanation, I'm still clueless finding where Photoshop stores this layer info since there's no layers in a PNG afaik. I supposed it could create an alpha channel (even if nothing is transparent) but there's none when I check the channels tab. I'd need to compare both files with & without photoshop's layer modification.

                • 5. Re: Background layer default opening vanishing
                  JJMack Most Valuable Participant

                  PNG is not an Adobe format consult the PNG format standard and all PNG file are not the same. There is also a Super PNG plug-in (SuperPNG.8bi) you can install in Photoshop and save PNG file with some more capabilities.   I would think that most PGN files would not had a background layer for the main reason users save PNG file is because it has better color capabilities then GIF the other Web Image file format the supports transparent pixels.  Gif then will only have up to 255 mapped colors for the 256 color is transparent.