Compositing issue with Alph chanel

[ctasker]

Hi,

I'm trying to composite a rendered model onto a site photo. The model has areas of translucent materials and so simply cutting out the background in Photoshop after isn't going to work.

On a previous job I had been able to render TGA files that stored transparency info with the file thus removing the need to cut out the background but i can't seem to get it to work for me again.

 

I'm rendering out as a TGA file with the following settings: 32bits per pixel with Compress and Pre-multiplied Alpha ticked on.

When i open the image in Photoshop the background is black not transparent!

 

Can anyone tell me if there is some other setting i'm missing to make this work properly? Maybe it could be a setting in Photoshop alternatively.

Any light shed would be apreciated, thanks

[JamesTaylor]

turn off the compression on the TGA when saving, bring the image into p'shop then go Selection > Load Selection and select the alpha channel in the dialog box which appears.

 

James

[ctasker]

Thanks for that james,

That should do the trick.

My photoshop skills are not what they could be.

 

I was previously able to open up a rendered TGA file without having to specifically select the alpha chanel though, the rendered image would be visible but you could see right through to the checkered background, puzzled as to why that doesn't happen anymore.

[JamesTaylor]

yeah,

 

i remember others being able to do that a few years ago too! its strange but that is the way i seem to have to do it now!!

 

maybe someone else could help us solve the mystery! any suggestions?

[diegofer_9]

Hi,

I am not sure if I can solve the mistery, but what I found to be the reason is the version of photoshop. I use to get the same transparent background with photoshop 7.0 but I recently updated to photoshop CS and I get exactly the same thing you are describing, so...there is my veredict: the version of photoshop changed the settings.