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Dragosvr92
Participating Frequently
December 24, 2016
Question

png transparency to Alpha channel

  • December 24, 2016
  • 2 replies
  • 32362 views

In GIMP, by default, when you load an image with existing normal-Transparency, it automatically creates an Alpha channel with that transparency.

No matter what i do in Photoshop, i cannot reproduce this functionality. You have to Manually select and erase the area you need transparent for no reason.

How can we make it so Photoshop creates an Alpha channel by default when we erase something in the actual image?

Photoshop Should simplify the Alpha Channel transparency. If i use the eraser tool to delete something, that should apply for the Alpha channel also and profile full transparency capabilities. Bit off how a free program manages like gimp this better than a paid professional software.

Thanks in advance.

2 replies

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FogLine_dude
Participant
November 11, 2018

I also need to sometimes use an alpha channel with .png instead of what Photoshop translates as layer transparency. In the specific case of a .png file, an existing alpha channel is translated by Photoshop to layer transparency. It doesn't do this with Tiff files or Targa files, which can also carry an alpha channel. Maybe it has to do this because of the .png format? Not really sure why it does this. One workaround is to save the file as a Targa or Tiff if your other software supports that.

However there is a way to save the .png from Photoshop with transparency, which your other software will probably see as an alpha channel. To do this, you don't need to add an alpha channel to the .png. Assuming you have a single layer with transparency in Photoshop, use the "Save for Web" option a couple of lines under the "Save As" line in the File menu. In the large dialog box that then opens, choose PNG-24 and check the Transparency box. Until you test it, of course keep your old file, because this may or may not work in your other application.

good luck!

T
torbach
Participating Frequently
December 13, 2018

nope; will not work, (that's a legacy system at this point btw) png-24 tells you it is not capable of encoding RGBA8888 which is 32bits

it is RGB888 + transparency and writes transparency (which is on white*).... not alpha

photoshop will open png transparency into alpha channel [which is a confusing illusion of functionality]

*so this process of save_for_web, transparent pixel are white,

you cannot save non-white pixels 100% transparent in photoshop

davescm
Community Expert
davescmCommunity Expert
Community Expert
December 24, 2016

On opening your PNG file, you can quickly produce an alpha channel using Layer - Layer Mask - From Transparency.

See the link below which explains why a PNG opens as a layer with transparency and not as an Alpha channel

Photoshop layer transparency masks, alpha channels | Scene7

Hope that helps

Dave

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    Dragosvr92Author
    Participating Frequently
    December 24, 2016

    I see... Although, i need my image to have an independent Alpha channel, and not one that extends from a layermask.

    So after i make a Layermask from Transparency, i have to Right click the mask, Add Mask to Selection, Go to the Channels tab, Create new Channel, and Push Ctrl + i to inverse the selection. And delete the created Mask from transparency.

    So much work when they could just add the Alpha channel from the existing transparency automatically.......

    But at least i figured out how to do it, so i wont have to get gimp each time, to avoid drawing over an already transparent area...

    Someone posted a link here to this plug-in (SuperPNG), but they deleted it....

    I installed the 64bit file, but i have no clue how to access it, or if it does what i want it to do.

    Thanks

    davescm
    Community Expert
    davescmCommunity Expert
    Community Expert
    December 24, 2016

    If you want to delete the mask but keep the channel it is quicker to :

    Right click the channel for the layer mask in the channels panel and duplicate it (this will give a new Alpha channel)

    Then delete the mask

    Dave

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