Simple compositing - watermark

[arumiat]

Hi guys

I have a straightforward compositing step that I can do but I’m not sure it’s the ‘correct’ way as I get some weird artefacts sometimes.

I have an original image 1280 x 720 png created in a .blend file.

I have a ‘watermark’ 1280 x 720 png created in another .blend file.

I want to overlay the watermark over the original.

I can do this by opening up 2 image input nodes in a new .blend file, selecting both images via dropdown, adding a ‘math’ node set to add and attaching the watermark via the alpha channel.

Is this the most efficient way? I seem to get some artefacts of the watermark image sometimes…

Thanks in advance

[3pointEdit]

Um, performing an add function only alters the RGB pixels. So I’m not sure how you think you are using the alpha channel? Perhaps provide a screen cap of your nodes?

You could use the add by applying white or original watermark image then send the watermark to the factor input.

Otherwise use the alpha over node, assuming you have an alpha channel from the watermark image.

[arumiat]

Hi 3pointedit

This was the setup I was using, oops!

I got it to work using the alpha over node as you suggested, many thanks.

I couldnt figure out the other node setup that you were advising? Factor input of which node?

Lastly when you hit F12 and render, is the rendering literally just combining the two images right, no loss of quality?

Thanks again
T

Attachments

[arumiat]

Something I’ve noticed though using the alpha over node is that it darkens the original render as you increase the strength of the alpha. How can I avoid this?