Skip to main content
B
buck-w
Known Participant
April 19, 2022
Answered

So Where's The Alpha?

  • April 19, 2022
  • 4 replies
  • 2508 views

I color keyed a video in Premier and saved out an image sequence with transparency (the key mask is now the 8bit portion of a 32bit image). How come when I load one of the saved files in PS, I see the transparency (checkerboards), but when I look at the channels, there is no alpha channel?

 

And while we're at it, I have a 32bit, uncompressed tiff generated from batch processing the images above.   It loads in PS and shows an Alpha 1 channel with the 8bit mask displayed in that channel as I would expect.  But unlike the above, this 32bit image displays black in the transparent areas, not the checkerboard.   Also, I cannot save this 32bit tiff to a PNG with transparency in PS.  Both examples are included.

 

So some 32bit images show checkerboards and no alpha channel, some show the 24 bit images as is, but have an Alpha 1 channel loaded.  Obviously I do not understand something about something here.

This topic has been closed for replies.
Correct answer davescm

Thanks for the step x step.

Click on the Alpha channel then load it as selection (?)

I go to Channels and highlight the Alpha 1 Channel.  Load as Selection?

Nothing I do seems to work.


Yes step two is simply click on the Alpha channel then on the symbol at the bottom of the panel to load it as a selection. 

There is a shortcut which is to Ctrl+Click on the channel

Dave

4 replies

Stephen Marsh
Community Expert
Stephen MarshCommunity Expert
Community Expert
April 19, 2022

What happened to the term RGBA? When was it replaced by 32bit (24+8)?

    D Fosse
    Community Expert
    D FosseCommunity Expert
    Community Expert
    April 19, 2022

    Not because I'm an expert on this, but I remember former PS engineer Chris Cox wrote several long posts about transparency and alpha channels, the gist of which was that they weren't the same thing. Here's one that I for some reason kept. He's talking about alpha channels here:

     

    I don't have any opinions here. But maybe this is what he was talking about.

      B
      buck-wAuthor
      Known Participant
      April 19, 2022

      Interesting to read.

      Complete BS.  Photoshop is the one being obtuse here.  A file is 32bit and has a mask within, or it does not.  I have two 32bit images that act differently.  Very confusing.  I don't think it is standards so much as PS evolutionary weirdness.

      c.pfaffenbichler
      Community Expert
      c.pfaffenbichlerCommunity Expert
      Community Expert
      April 19, 2022
      Complete BS.

      It seems hard to take you seriously when you make such a statement. 

      If you want to use Photoshop but refuse to use proper Photoshop-terminology you are setting yourself up for problems. 

       

      Batched in QFX. 

      Why and what? 

      If you want to process these files to incorporate actual transparency (as your customer seems to want) you can do that in Photoshop, as @melissapiccone indicated, and it should be possible to automate that process with Actions, Batch, … or at least with a Script. 

      melissapiccone
      Community Expert
      melissapicconeCommunity Expert
      Community Expert
      April 19, 2022

      If you load the alpha channel as a selection, you can use it to create a layer mask to create transparency and then save the image as a png. 

      Melissa Piccone | Adobe Trainer | Online Courses Author | Fine Artist
        B
        buck-wAuthor
        Known Participant
        April 19, 2022

        As stupid as I sound, please elaborate.

        c.pfaffenbichler
        Community Expert
        c.pfaffenbichlerCommunity Expert
        Community Expert
        April 19, 2022

        In Photoshop Layers other than the Background Layer have something called »Transparency« and that is not intended to appear as a separate Channel in the Channels Panel, but it can be converted to a Layer Mask.

        And what you call »32bit« is, in Photoshop under Image > Mode, called »8 bits/channel« (referring to bits per channel, not overall). 

        In Photoshop »32bit« would usually refer to images with 32 bits/channel. (edited)

         

        »And while we're at it, I have a 32bit, uncompressed tiff generated from batch processing the images above.«

        Please explain the details. 

          B
          buck-wAuthor
          Known Participant
          April 19, 2022

          Batched in QFX.  Doesn't matter.  The output is a 32bit tiff.  The is alpha in the alpha.  What can I do to save it as a png, where the transparency that should derive from the alpha is transparency in the png?

           

          A client is asking for that right now, actually.

          Thx.

          Terms & ConditionsAccessibility statement
          Using the community Terms of use Privacy Cookie preferences Do not sell or share my personal information ad choicesAdChoices