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View Full Version : Need help with alphas.

Kotayus
06-10-2003, 09:39 PM
Ok...ive never really used alpha channels, outside of masking in c4d...and im curious...i rendered an image out with an alpha...i want to color the background with a gradient...and do the normal post effects in PS...my question: is this done with the alpha? do i do what i want IN the alpha channel? i cant seem to get anything to work right...maybe i have the wrong idea of what the alpha chanel does in PS? squid for instance uses the image...at huge resolution for his BG's... i KINDA want to do a similar thing...but i want to make a gradient...without it affecting the image...is this possible?

TIA
tcastudios
06-10-2003, 10:01 PM
If I understand you right, render your pict with alfa activated in render settings.
Open in PS and select alfachannel in ChannelsTab. CommandClick(Mac) on the alfa layer to make a selection. Invert if necessery and delete the black area. Then delete the alfachannel. Make a new layer, put it in the bottom, under your pict and make a gradient.

Cheers
Lennart
Kotayus
06-10-2003, 10:13 PM
that is what i want to do...but when i delete the alpha...it doesnt seem to be effective...i followed what you said...but something (most likely me) is not working...i followed what you said a couple times...and its just not doing it

the bottom layer has the gradient...but the only way i can see it is to make the blend layer different...when i delete the alpha, it seems to then have no effect...
tcastudios
06-10-2003, 10:37 PM
Deleting the alfa have no visible effect per see, itīs just that it is not needed anymore. The only thing you use the alfa for is to get a selection (the crawling ants line). If you have got the selection working(by using CommandClick on the alfa channel if you have a Mac, on PC I think its ControlClick), go to LayersTab and select your C4d layer. The selection should still be active. You will probably have to invert the selection otherwise you will cut your pict instead of the black area.

Oh, also when you open your pict itīs most likely labeled "Background" in italics. If that is the case you first have to dubbleclick in the layer making it a editable layer.

Cheers
Lennart
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