CS2 alpha problems

Now I am really flummoxed! I couldn’t upgrade my PS7. It was installed on my computer by an old boyfriend and when I tried to upgrade, I couldn’t. So, I upgraded to PhotoShop CS2.

If I use an old PS7 file everything works fine. However, when I make a new file in CS2, the alpha doesn’t work. It is there, I can see it and when I click on it to select I see the red background.

I then save it to tga format selecting 32 bit. At this point everything seems normal. However, when I check the file in the preview window it has a white background. If I open the same file in PS7 and save it to tga every works fine? Luckily, I hadn’t deleted PS7.

I searched the forums for CS & alpha and saw a thread about using a different alpha plug-in. I tried it, but it didn’t work. Do I have something set up wrong or not configured correctly?

Jen

Hi Jen!

I'm not sure what you are doing, and therefore not sure what is going wrong. But I have CS2, and love it. (It has all kinds of features, like the Warp filter, that make designing clothing and things worlds easier than any earlier version of Photoshop.) And it does make .tga files with the proper transparncy for SL. I upload them all the time.

It sounds like you know what you're doing, so I'm assuming that you don't have more than one alpha channel.

Is it possible that the black in your alpha channel isn't completely black? It's almost impossible for human eyes to tell.

Try this; open the Channels palette, and click on the Alpha channel, so you get a black and white image of that channel and nothing else. Then, with the Info palette open, run the cursor over the areas that are supposed to be transparent.

In the upper left corner of the Info palette there's a K, which tells you the percentage of black. It needs to consistently read "100%" for the channel to give you true transparency.

If it doesn't, honestly the best way to fix it is to delete that channel, go back to the RGB image, hold down the Command/ctrl key, and click on the thumbnails of each layer. (Right on the picture, not on the words. Clicking on the picture will load the non-transparent pixels as a selection. Clicking on the word will simply select the layer, since you can select multiple layers in CS2, and the Command/ctrl key lets you make non-continuous selections.)

Hold down shift and keep clicking to select the contents of more than one layer, of course.

When you have them all, choose "Save Selection" and you'll have a perfect Alpha channel.

In fact, if you don't care why it's not working, and you just want to fix it, you can do that firrst.

Whatever is happening, that should take care of the problem.

Thank you Robin for attempting to help me.

The alpha is there. I made it by CRTL clicking on the thumbnail to select the items in the layer then I used the Save Selection to make the alpha channel. I can see it and, when I use your suggestion of checking the K value, it is 100% black.

With the wanted layer(s) and alpha channel selected, I see the layer(s) and everything black on the alpha shows up red or pink, when looking at layers. I then Save As and select TGA. I get a dialog box saying it will be saved as a copy. There are also two yellow yield (attention) signs on the alpha channels box and the one below it. The two boxes are grayed out and there is no check mark in them. However, I get the same dialog in PS7 when I save. I select Save and tell it to use the 32 bits/pixel.

If I do this in CS2 when I go to preview under Upload in SL, I see a white background or a colored one, if I used a colored background. If I do it in PS7, I get a transparent background.

So, like, what is the matter?

Jen

I dont know if this helps jen, and I am not as expert as robin, but the behaviour you describe happened to me all the time in CS1. I had to flatten the image and delete all layers before it would same the alpha corrcectly. This was *fixed* when I started with CS2 though so its mystifiying.

If you didn't already do it, perhaps a very *complete* deletion of *all* pshop files, even from your library and the system library, followed by a complte re-install? this suggestion is base on the idea that yo umight have parts of various pshops installed at the same time, but it's just a guess.

Hi Jen,

I just tried various combinations of things to reproduce your behavior, and the only thing that I found that would do it is having more than one Alpha channel.

Other things, like trying to save in CMYK mode, would eliminate the Targa choice altogether, but having more than one Alpha on a layered file would do exactly what you said; warning signs on both Layers and Alpha. (All layered files have warning signs on the Layer, by the way, because you can't save layered .tga files.)

Are you sure that you have only one Alpha channel?

If that's not it, then the only thing I can think of is to send me the file, and I'll take a look at it. I feel like I'm picking things off a salad bar with chopsticks in the dark, here. Without seeing the file, it's really hard to tell what went wrong where.

If I can't find anything, then perhaps Dianne's rather drastic solution might be the only thing left. What platform are you on? I know that if you are on a Mac, and install PS CS2 before a System upgrade, it does funky and weird things, such as not opening a file when you click on it. The fix for that is simply re-installing the program after you have installed the OS.

But other than that, I dunno.

Let me know about the alpha channel(s), platform, etc. It can be done, though, so there must be some way for you to do it, too!

Robin, I often have more than one alpha channel in the channels tab. However, I only use one at a time. Meaning I select the one I want to use. I have done this in PS7 without any problems.

I use MS XP Pro with the SP2 upgrade.

Jen

Ah! Well, that's the problem, then.

There can be only one.

The .tga format can't tell which one you want to use. So, before you can save it for Second Life, you need to delete all the extra channels. (Yes, I know that PS 7.0 didn't work that way, because (I believe) it ignored the Channels and just used the transparency from the image. But that had a number of problems of its own, and Adobe listened to the uproar and fixed it very quickly.)

Personally, I have a PS action that flattens, shrinks and sharpens, since I tend to work at 1024x1024 or larger. Once that's done, I delete the extra Alpha channels if any, save a copy as a .tga file, and then use the History palette to return to before the Flatten. I know, that's an extra step or two, but it works for me to keep me from overwriting the layered file since I always do it.

But, anyway, once you remove all the channels except the one you want to use for SL, you'll find that you can save as a .tga file and upload to SL without any problems.

... and remember that because layer masks are ignored by the export-to-tga, they make a good alternative to channels for many purposes.

Sometimes, I will have a layer or two with nothing on them, but they have masks that I use as saved-selections. This means that the only channel I ever have is the one that I specifically create for the SL alpha.

(obviously, for non-SL work, I continue to use channels where they are more appropriate)

Great tip, Ben! Thanks!

Thank you everyone for your help. Robin, I will move all of the extra alphas to layers.

Jen

Also, when you get all of the transparentcies you need, and the layers merged visible, you can save the pic as a non interlaced png and then put it in Imageready cs 2 and just go to file>export>original document and save as tga. As in photoshop, it will bring up the 16, 24, 32 bit save option. i have noticed better alphas that way. it works great with half transparentcies!

Interesting. Can you define "better alphas"? This is a bunch of extra work per texture, and a process I would never have thought up in a million years, so I'm assuming you must be seeing some benefit from it or you wouldn't be doing it. Can you please explain exactly what's better about it? Maybe post some pics?

Well, don't have any pic handy at the moment, but will try to get some up for next post.
What i was speaking of, was that instead of the normal way of making a selection around
your texture, inversing, going to the channels tab, saving selection as channel, (which creates the alpha), turning the visibility of the channel on and then saving as a tga,
You can simplify all of this in a couple steps, as stated before, getting all your transparentcies correct, export to png, open in imageready, and simply export to tga.
It automatically makes the alpha for you. I have noticed that it catches half transparentcy detail that the old method might leave out. let the program do its job for you so to speak

Thanks for the explanatrion. Okay, I see what you're doing now. The issue I have with this is that visible transparency in my TGA's is exactly what I don't want. Visible transparency means potential artifacts, the most common of which is white haloing. Using any sort of automated alpha creation means giving up control. "Letting the software do it's job" means risking it making mistakes, which it tends to do more often than not. It also means that if you want to go back and make changes to the transparency or to any other aspect of the image, you're going to have to do a lot of re-work.

In other words, don't put the cart before the horse. You want the alpha to dictate the transparency, not the other way around.

The only method for creating alphas that I've found to work flawlessly each and every time, and is completely non-destructive, is to have no visible transparency whatsoever in the image itself, and to paint it onto the alpha. This is why alpha channels are still in use today, completely unchanged, despite the fact that they're almost as old as computer graphics itself. It's something that just works.

If you have a need to actually see the transparency as you work (which once you get used to it, you really don't), there's a much simpler way. There's no need to open a second program or to play around with exporting to different formats. Here's how:

1. Put all your layers into a layer set.

2. Give the set a layer mask. Do this by clicking on the name of the set in the Layers Palette and then clicking on the "Add Layer Mask" button at the bottom.

3. You'll see a new white thumbnail appear directly between the layer set's icon and the layer set's name. This is the thumnail for the mask. It should be active by default, but click it once just to make certain (click the thumbnail itslef, not the name, not the little chain link, the thumbnail and only the thumbnail). At this point your image will appear totally opaque since the mask is all white, as you can see in the thumbnail. Grab a black paintbrush (or the eraser if you prefer) and start painting where you want the transparency to be. For "half transparency" as you put it, simply paint with a gray brush or with the eraser on a 50% opacity setting. You'll see the checkerboard show through instantly as you work.

4. Once you've got the transparency the way you want it, simply save the mask as an alpha channel, and then delete the mask. Save the file as 32-bit TGA and you're all set.


That's all there is to it. It's simple and very effective. With this method, you can use all the painting, erasing, and blending tools that you would have with your old method to "get the transparency correct" , but without the extra steps that come with changing file formats and exporting to another program, and with the added benefit that you're doing it completely non-destructively since you're only altering a mask, not the actual layers. If you want to go back and change something later, you can do it easily.

I have PhotoShop CS2 v9.0, and what Robin said works...



Of course when you do "Save Selection", save it a new channel called Alpha.

Delete any other layers you have, only have one layer.

Worked perfectly...

Thanks, Norman!

That technique works in all versions of Photoshop, from the very first one that used Layers (I think it was 3, or some such number.)

I use all kinds of transparency in my Photoshop layers; but I also use a solid layer on the bottom of the stack, to block the "checkerboard" and keep semi-transparent pixels, like those around the edges of things, from being merged with white. (Which is what happens if you can see the checkerboard, and where the "white halo" comes from.)

I absolutely agree with Chosen that you want to use masks, never the eraser, to draw in transparency. But a lot of the time, I'm not eliminating pixels, I'm drawing them on to transparent layers. It's just the way I work.

By the way, you can have all the layers you want.

It's Alpha channels that can have Only One, for a total of four channels; Red, Green, Blue and Alpha. (It doesn't matter what you call it; that fourth channel is your Alpha.)

Hope this helps!