File Size with/without Watermark

[dbaldock]

Using some command line tools on my Linux PC, I created a Watermark file that contains black text on a light gray background, "Copyright © David R. Baldock", and is saved as a PNG file (21.8 KB).

When the Watermark is added to JPG files that came directly from my camera using the composite command line tool (see ImageMagick - composite), the watermarked files are ~200 KB to 500 KB larger than the original.

When the Watermark is added to PNG files that were created from TIFF files from my scanner, the watermarked files are ~10 KB to 100 KB larger.


How much larger are your Watermarked files than the originals?


Here's an example of an original, and the watermarked version of a JPG file from my camera. The file size difference is ~475 KB.

Original photo - Cheddar's Restaurant, Webster, TX (1024x680)
(Click on the image to see the full size 4288x2848, 6.4 MB photo)



Watermarked photo - Cheddar's Restaurant, Webster, TX (1024x680)
(Click on the image to see the full size 4288x2848, 6.9 MB photo)

[Patti Edens]

Not sure if what I did will help answer your question, but your post made me wonder what my watermark (just a photoshop brush) added.

I saved a few varying sized TIFFs as jpegs using the same quality setting. Then I watermarked all of the jpegs and did a Save As, again using the same jpeg quality settings.

The amount added by the watermarked varied quite a bit. I haven't done enough of them to find any pattern.

Here's what I saw:



Example photo and watermark ...

[dbaldock]

Thanks for your reply.

I did some more reading about the ImageMagick commands, and followed some examples to create a 3D embossed style Watermark to place on my photos. It's a slightly more subtle design than the first type I tried. The Watermark.png file is 38 KB, rather than the 22 KB of the first one, but the resulting Watermarked image is still 6.9 MB.

=====
For those who may be curious, here are the commands that did the task:

convert -size 1150x90 xc:grey80 -font DroidSerif-BoldItalic.ttf -pointsize 70 -gravity center -draw "fill grey20 text 0,0 'Copyright © David R. Baldock'" Watermark_fgnd.png

convert -size 1150x90 xc:black -font DroidSerif-BoldItalic.ttf -pointsize 70 -gravity center -draw "fill white text 1,1 'Copyright © David R. Baldock' text 0,0 'Copyright © David R. Baldock' fill black text -3,3 'Copyright © David R. Baldock'" +matte Watermark_mask.png

composite -compose CopyOpacity Watermark_mask.png Watermark_fgnd.png Watermark.png

composite -dissolve 100 -gravity southeast ( Watermark.png -resize 100% ) "$FILENAME" "$FILENAME_wm.JPG"
=====


I added a -2 to the resulting Filename, since I already had a DSC_0587_wm.JPG from the first try.


3D Style Watermarked photo - Cheddar's Restaurant, Webster, TX (1024x680)
(It's in the bottom-right corner.)
(Click on the image to see the full size 4288x2848, 6.9 MB photo)

DSC_0587_wm-2 by David.R.Baldock, on Flickr