Alpha Channels in Photoshop CS

I've been using FF a lot recently to make transparent textures for 3D models and then saving them in Targa format. To save a TGA in Photoshop CS with alpha channels, you need to create a fourth channel for the Alpha then flatten the image. This can be done manually or automatically when saving as a copy.

When doing this automatically, or when flattenning a single layer with transparency, Photoshop will automatically use a white background for the areas where there was image transparency. Unfortunately, this means that anywhere that was even partially transparent will be lightened slightly because of the white background (the more transparent a pixel was, the greater the effect of the white background, but also the less you will see the pixel in the end.)

This means that by default, alpha images end up with nasty white halos around them. It's often not too hard a workaround to select a similar colour as the filter and fill the transparent areas with this colour before flattening. But for filters with more colour variation, this doesn't work. For these filters, I have to render them once with no alpha channel, render the FF alpha channel to a new layer, and then copy it to a new Alpha channel in Photoshop.

I'd like to see (if possible) an option to render a texture to Photoshop in RGBA format, so that the RGB channels are transferred without any alpha. This would cut out the tedious re-rendering processes. Is it even possible?

The attached image shows how these halos look (right) compared with the image generated with two FF passes (left). It's a lot better on the left in both versions - with a white background, the wires appear thinner than they should because the halo blends in with the background.

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onyXMaster wrote: If you are talking about rendering into separate Photoshop channel (i.e. alpha goes to alpha channel instead of layer transparency) -- I'll go check it out tomorrow, but I seriously doubt that we can do it.

Yeah, that's exactly what I meant.

I've played around with other formats, and it's the same result for PNG and TGA - and I wouldn't really consider any other formats for transparent textures.

It would be a shame if you can't do it, but if that's the case I think a helpful alternative workaround would be the ability to turn off alpha (perhaps through the "Channels" options?) from the final render. That way I wouldn't need to build this functionality into the filter (ATM I can use a switch and a Use Alpha checkbox like in the Hair filter, but it would be great if this was part of the software.)

If not, thanks anyway for looking into it