Photoshop and transparency in the TGA file format

J
Posted By
john
Feb 22, 2006
Views
415
Replies
3
Status
Closed
Hello,
in Photoshop CS2, if I have an image with transparency, and I save it in PNG format, when I reload it I will get again transparency. But if I save it in TGA, I won’t. Even if I selected 32bit. Is there any way to make it save and load transparency using 32bit TGAs? Please note that I even tried to create an alpha channel from transparency (using Image/Calculations..) but, while the newly created alpha channel will be saved in the TGA file, it won’t be reloaded. But, even worse, the saved alpha/transparency IS NOT PERFECT. The edges look bad then.

But if I save e.g. in PNG, and then import the PNG into Artgem and resave it in TGA, it works. Even when I reload it.

Does this mean that Artgem supports TGA in the right, proper way, while PS support of TGA is bad/crippled?

And here we’re talking about PS 9.0, not 1.0 beta.. how’s it possible?

Thanks,
John

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NS
Nicholas Sherlock
Feb 22, 2006
wrote:
in Photoshop CS2, if I have an image with transparency, and I save it in PNG format, when I reload it I will get again transparency. But if I save it in TGA, I won’t. Even if I selected 32bit. Is there any way to make it save and load transparency using 32bit TGAs?

Right click on the thumbnail of your layer, click "Select layer transparency". Click the Select menu, "Save Selection…". Save it as a new channel in your image. Then make sure "Alpha channels" is ticked when saving your image.

Cheers,
Nicholas Sherlock
J
john
Feb 24, 2006
Hello Nicholas Sherlock, you wrote:
wrote:
in Photoshop CS2, if I have an image with transparency, and I save it in PNG format, when I reload it I will get again transparency. But if I save it in TGA, I won’t. Even if I selected 32bit. Is there any way to make it save and load transparency using 32bit TGAs?

Right click on the thumbnail of your layer, click "Select layer transparency". Click the Select menu, "Save Selection…". Save it as a new channel in your image. Then make sure "Alpha channels" is ticked when saving your image.

Cheers,
Nicholas Sherloc

Thank you Nicholas, now transparency is saved correctly to the bit, I verifyed. However, there’s a halo around the image (on the edges where there was *semi*transparency).
Since the transparent parts are saved with white RGB values, I tried to use a black background to fill transparent pixels but it won’t give the proper results. I think it’s a "matte" problem, i.e. those pixels that are semi-transparent will be saved against a wrong background by Photoshop.
How could I solve this problem? To sum it all, now Photoshop will save the correct alpha, but RGB will be correct only for opaque pixels, semi- transparent ones will have RGB "matted" towards a wrong background color.

Moreover, is there *any* way in Photoshop to LOAD transparency from an alpha channel? Imagine I have a solid image, I want to make the pixels more or less opaque by using a mask. Is it possible? Cutting works only for the pixels that I want to make completely transparent, and anyway I’d like to have a pixel by pixel precise control.

Thanks again a lot,
John
TN
Tom Nelson
Feb 25, 2006
If you’ve saved transparency as an alpha channel…
1. Within the SAME image: select>load selection
2. From ANOTHER image (which must be open as well) select>load selection and choose from the Document pop-up.

Tom Nelson
Tom Nelson Photography

In article <43fec291$0$28065$>,
wrote:

is there *any* way in Photoshop to LOAD transparency from an alpha channel?

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