We cannot know why your signature has a white background without knowing how you made your composition. It could be as simple as deleting a solid layer from your comp. If you have enabled the Transparency Grid in the Composition Panel and there is transparency then you simply need to add your signature comp to the render cue and choose Lossless With Alpha from the output module templates. If you cannot simply delete a background layer then you have to tell us or show us exactly how you created your animated signature. If simply rendering Lossless with Alpha fixes your problem please do some reading on rendering. You're going to be wasting a lot of time if you don't learn about formats and workflow. After Effects Help | Basics of rendering and exporting
Thank you Rick for your kind prompt response, I appreciate your time. I usually solve all the technical problems I face through my classroom in a book series, or by watching experts videos
but this one I couldn't figure out correctly anywhere, sorry about that. The steps I followed are as follows:
1) I scanned a handwritten signature and I saved as a TIF image
2) I imported the above mentioned image in Adobe After Effects
3) I used the pen tool to mask the signature
4) I created a white solid composition
5) I copied the masks to the White solid composition.
6) I copied the white solid masks to a new video composition with same size of my Premiere pro project 1920x1080 and I started to amend the brush size, hardness...etc under stroke
7) I made the end of the stroke feature to be 0% at the start
8) After 3 sec. I made the end comes back to 100%
9) I checked the animation of the signature and it was great, I made the length of the composition becomes 20 sec in length to match the handwriting natural speed
10) I resized the composition to show a size of my signature which does not exceed a 10% of the quarter of the right corner of my video I opened the Premiere Pro and imported the compostion
11) The composition showed an animated signature in Premiere Pro but with a white background which I failed to make it transparent.
Thank you once more.
Your problem is probably that you are using stroke and applying that to the solid. You need to write on transparent or reveal original, then you need to export with an alpha.
I still don't know much about your project. A screenshot with all properties revealed for the layers in question would help a bunch.
Rick, can you forget about what I did, I am ready to make it again from scratch, it's fun for me, do you mind guiding me with simple steps? how do I achieve my target (animating my signature over the video) I'll figure what I missed according to these steps. That is ofcourse if you know how. Thank you.
All you have to do is change stroke to Reveal Original or On Transparent.
It would help if I saw the AE comp and not the Premiere Pro Sequence because the problem lies in AE not PPro.
You still need to show me the effects Control Panel. Just change that project fixed.
Thank you Rick, while waiting for a fruitful response from you, I could figure a solution to the problem by adjusting the opacity of the composition in AE, and making some slight editing in Premiere Pro. Thanks God I am now pleased with my results and need no more help. At least you showed a lot of care in responding promptly. Regards
I may add that I got a better result in achieving my above mentioned target by selecting the opacity blend mode "Linear Burn" and changing the position of the signature under motion effect, (see the above picture). NB. Thanks God I could manage to solve this problem which took a lot from my time and this never happened before except in Arabic titles which is unfortunately not supported by Adobe.