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Generating a transparent watermark .png

Jun 27, 2011, 21:51
Post: #1
Generating a transparent watermark .png
I want to generate a transparent embossed text watermark .png file that can be batch-applied in Lightroom. I get how to apply a bump map to an image inside GIMP, but I haven't figured a good way to get an otherwise transparent .png with just the watermark.

Ideally, this would be totally transparent except for lit areas (white, at varying degrees of opacity) and shaded areas (black, with varying degrees of opacity). In GIMP, I can apply a bump map to anything opaque -- lightening and darkening the color, I guess -- but I can't apply it to a transparent layer.

If there's no straightforward way to do that, I imagine I could bump map onto gray, turn the resulting light grays into a mask for a white layer and the dark grays into a mask for a black layer. The content of the watermark will change, so it would be outstanding if there's a simpler way to do this.
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Jun 27, 2011, 22:20
Post: #2
RE: Generating a transparent watermark .png
Apply the bump map to a some gray. It you want only the shading/lighting, do a color selection with no treshold on your original gray and erase. If you want to keep only the darks or lights,
add a layer mask, initialized from the grayscale copy of the layer, and use the Levels tool to transform everything below some value to pure black (for the darks you'll have to invert the colors first).

If you can tell me exactly what LR expects I could be of more help.

You can also use ImageMagick's 'compose" tools to apply bumpmaps to your pictures outside of LR.

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Jun 28, 2011, 00:18
Post: #3
RE: Generating a transparent watermark .png
Yep that's about what I figured, and once I have the sequence down it shouldn't be that big of a deal in the future. I just figured there'd be some shortcut.

Lightroom just superimposes a .png file at whatever level of opacity you specify. It does that while exporting processed images, so there's no extra step for watermarking. I'll check out ImageMagick too.

Thanks,
Drew
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Jun 28, 2011, 01:01
Post: #4
RE: Generating a transparent watermark .png
(Jun 28, 2011 00:18)dtronvig Wrote:  Lightroom just superimposes a .png file at whatever level of opacity you specify. It does that while exporting processed images, so there's no extra step for watermarking.
Not really embossed then...

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Jun 28, 2011, 07:50
Post: #5
RE: Generating a transparent watermark .png
Not embossing the underlying image, no. Just overlaying some percentage of this "embossed" watermark png, so the watermark doesn't have to be applied inside GIMP.
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Jan 16, 2012, 14:55
Post: #6
RE: Generating a transparent watermark .png
Here are two plugins to add watermark images and text easily -
http://www.skipser.com/p/2/p/how-to-wate...-gimp.html
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