Photoshop CS2 Alpha Problem

Hello, I am having a problem with my Photoshop CS2. When I save a .tga file or .psd file with a mask as alpha and open it back up it is no longer alpha and the background is white. I am having the same issue if someone sends me a .tga or .psd file that is alpha with a transparent background. I haven't always had this problem it just started lately. Is there something I need to change in my settings to fix this issue or is this a bug of some sort? If anyone could please help me out I'd appreciate it. Thanks!

Is very tricky to make the alpha channel on PS. I'm not on my home pc now, but if you IM me in world I will send you a NC with step by step instructions.

It's not tricky at all, and fully detailed instructions are sticked at the top of this forum, in both written and video form. You can make it tricky if you want, sure, but it certainly doesn't need to be. In most cases, it's three clicks. It's very, very, very simple (even if not necessarily obvious the first time you do it).

Anyway, from the post, it doesn't seem like Tara is asking how to make an alpha channel. She appears to be asking about something else entirely.


Tara, are you saying that the alpha channel itself is missing from the file, or simply that the background in the image appears white when you open it?

If it's the latter, that's perfectly normal behavior. By default, Photoshop will not automatically assume an alpha channel is a transparency map. This is because, outside of SL, alpha channels are used for all sorts of purposes. Transparency is just one of the many possible things any particular channel might be used for. And Photoshop is smart enough not to make any assumptions about what you might be wanting to do in this regard.

It's not Photoshop's job to equate the alpha channel with transparency or with anything else. That's the job of whatever program or device the file is intended for. SL happens to consider channel 4 to mean transparency, but in another application that channel might be a bump map, or a specularity map, or a spot color map, or anything else you can think of. Therefore, while Photoshop allows you to add as many channels as you want to an image, it won't actually do anything with those channels until you tell it to.

If you want to tell PS that you wish to see an alpha channel as a transparency map, you do so by copying the channel to a mask. If the file is layered, put all the layers into a group, assign a mask to the group, and paste the contents of the alpha channel onto the mask. If the file is layerless, like a TGA, double-click the background layer in the Layers palette to change it to a normal layer, apply a mask, and paste the alpha channel's contents onto it. Or, in either case, you can save the step of copying and pasting by ctrl-clicking the alpha channel's thumbnail to form a selection, and then hitting the Make New Mask From Selection button at the bottom of the Layers palette.

Assuming this is indeed what you're talking about, then since you say the behavior of Photoshop seemed to be different before, I can only for two possible reasons. Possibility number one is you've only ever opened working documents before, and you've never actually opened a TGA after the fact. However unlikely that may be, it is certainly possible.

Possibility number two is you were using Photoshop 7.0 before, and you've only recently upgraded to the version you're using now. 7.0 was a deeply flawed version of Photoshop, in which Adobe, during what I can only assume was the worst localized outbreak of mentally debilitating disease in modern history, tried to change the rules. That version treated TGA files differently from all other progams on Earth, both before and since. Adobe's experiment with 7.0 failed miserably, as not only did it screw up established work flow habits for thousands of users, it created files that were incompatible with most other programs, and that were riddled with internal problems of their own (see the Transparency Guide for more on this).

By a miraculous coincidence of development timing, SL happens to be able to read 7.0 TGA's, but many other programs cannot. Adobe patched 7.0 to 7.0.1 a few months later, and have rightly never gone back down that path again.

Now, all of the of the above assumes is or course only relevant if your question was indeed why don't alpha channels create transparency directly inside Photoshop. If what you actually meant was that alpha channels are actually disappearing from your files, then I have no idea what might cause that. All I could think to say would be uninstall PS and reinstall it. Maybe your current installation got borked.

Photoshop never ceases to amaze me and as long as I have used it, still learning. I found the same issue in CS3, but also found another way of making a 32bit TGA out of CS2 & 3. I saved the file as a PNG and then re-opened it and re-saved as a 32bit TGA. It works, so far anyway.

I'm wondering why you would do that, Jeremey. Beside the fact that changing format twice adds a whole bunch of steps to your process, you're ignoring the fact that SL can upload PNG's. So if PNG is your format of choice, just stick with that. There's no need to flip-flop formats back and forth.

The only drawback to doing it that way is you sacrifice the control that comes with making an alpha channel by hand. There are countless situations in which keeping your transparency map as a separate element from you color maps is tremendously advantageous. If you're stuck in WYSIWYG mindest, you miss out on all kinds of benefits.

In any case, it sounds like right now you're using PNG sort of as a work-around to avoid making your alpha channels yourself. I would encourage you never to do that. If you have a valid reason for preferring PNG as a format over TGA, then there's nothing wrong with it. But if your only purpose for it is to pseudo-automate the alpha channel creation process, I can promise you that all you're doing is wasting time. Making an alpha channel is one of the easiest things in all of graphics, once you've learned how. It never ceases to amaze me, the lengths that people will go to simply to over-complicate things in order to bypass the ridiculously simple.