3 Replies Latest reply on Jul 23, 2010 11:09 AM by MTSTUNER

    Photoshop Elements 8.0 - Cannot export alpha to BMP files?

    Wheat Vitamin

      I am apparently unable to export to a BMP file with alpha information intact using Photoshop Element 8.0 (PSE 8).  (My current project requires BMP file format, not GIF, PNG, TIFF etc)


      As far as I understand, the BMP format allows an alpha channel, and indeed a hint for some support within PSE 8  seems to appear in the "BMP Options" dialog box (which appears when you click the menu item "File: Save As...", select "BMP" as the format, and click on the "Save" button).


      -    The "BMP  Options" dialog box has an option for saving to a 32-bit depth. I guessed that this would be 8 bits of red, 8 bits of green, 8 bits of blue, and 8 bits of alpha, but when I saved to this 32-bit depth format, and then loaded the newly saved file back into PSE 8, the alpha was missing. (If I saved to PNG format, then reloaded into PSE, the alpha was intact.)


      -  The "BMP Options" dialog box has an "Advanced Modes" button; clicking on that button leads to several radio buttons.  Each radio button that hints at an alpha channel (such as "A1 R5 G5 B5", "A4 R4 G4 B4", and  "A8 R8 G8 B8") has been disabled, whereas enabled radio buttons include "X1 R5 G5 B5", "X4 R4 G4 B4", and "X8 R8 G8 B8" .  I tried saving to "X8 R8 G8 B8", but the reloaded BMP file is missing the alpha.



      So my questions are:


      - Does PSE 8 currently export alpha information in BMP, and if so,

      -how do I fix my installation to re-enable those disabled radio buttons?

      - Alternatively,  is PSE 8 already exporting the alpha correctly by default in 32-bit depth mode, but a bug in PSE 8's BMP importer is not processing the alpha channel correctly?

      - If PSE 8 does not currently support BMP alpha information, but perhaps might in the future, when might we be able to get a patch?  Or is the internal development team at Adobe awaiting a critical mass of consumer demand for such support?


      My configuration is currently the following:


      • Version of Photoshop Elements:  8.0 (20091008.r.615486)
      • Operating System: Windows XP Home Edition  (Version 2002) SP 3
      • Memory: 2 Gigabytes RAM
        • 1. Re: Photoshop Elements 8.0 - Cannot export alpha to BMP files?
          MTSTUNER Level 6

          Pse8 should be able to save a bmp with an alpha channel.

          How are you making your alpha channel?

          How do you know that the alpha channel was not saved?


          Anyway, here's a quick rundown.


          1. Either use a file you want or make a new document.


          2. In the layers panel, add a new blank layer and put the logo

              or picture you want to use to define the alpha channel.




          3. Ctrl+click on the layer you want for your alpha (layer 1 above) to load the selection.

              Then go to Select>Inverse.


          4. Go to Select>Save Selection and name your new selection Alpha 1 and click ok.

              Then Select>Deselect.




          5. Save as a BMP. The 32 bit option should be enabled by default and no need to worry

              about the advanced options for now.

              The 32 bit option only means you are saving the image with an extra channel (RGBA)

              and is not same as an image in a 32 bit depth mode.



          6. Open your bmp file into pse8 and go to Select>Load Selection.

              You should see Alpha 1 listed.




          7. You can also check for channels in your image by going to:

              Filter>Render>Lighting Effects and at the bottom under Texture channels

              will be all the channels in your document.





          Hope this helps.




          • 2. Re: Photoshop Elements 8.0 - Cannot export alpha to BMP files?
            Wheat Vitamin Level 1

            MTSTUNER, thanks for replying and for taking the time to post your informative tutorial.  I didn't know that PSE 8 could export selection information to the BMP format.  I experimented with creating multiple layers, each with its own uniquely saved "new selection", and saved to 32-bit BMP.  However it seems that PSE 8 cannot export more than one selection (unless I'm doing something wrong).   Only one exported selection would just require 1-bit of alpha, so 7 bits of alpha space seem to be wasted...or used for something else?


            Your post indicates that PSE 8 interprets the 8-bits of alpha in a different way, unfortunately, than what I wanted. I was expecting that the alpha channel would be used to store  "transparency" (or more accurately, "opacity") information and when I currently export to a BMP file using the 32-bit option, opacity/transparency information is not preserved.   8 bits of alpha would nicely provide  256 levels of opacity,


            Such a capability seems to be hinted at with the disabled option of "A8 R8 G8 B8" in the Advanced Modes dialog (as detailed in my original post).


            I am rephrasing my original question to "Photoshop Elements 8.0 - Cannot export transparency (via alpha) to BMP files?"

            • 3. Re: Photoshop Elements 8.0 - Cannot export alpha to BMP files?
              MTSTUNER Level 6

              BMP does not support transparency, hence the use of an alpha channel.


              When you save a selection in pse, your really saving a channel, pse just calls it

              saving a selection since it does not have a channels palette.


              Maybe if we knew what the purpose and intended destination (other program)

              of the bmp files were, we could understand better.