the link for the png files is Dropbox - PNG (hopfully it works, I am not so familiar with dropbox)
In this folder there is the ABC.png file and some converted. All do not work and result in a crash of Lightroom.
How were these PNGs created?
I am able to use your ABC.png as a watermark if I open it in PS CC 2014.2.2, leave it non-color-managed, then save it back without any embedded color profile, both compressed and not-compressed.
My suggestion would me to make them RGB PNGs with an sRGB color profile, rather than indexed or grayscale.
The ABC was simply written on white paper, scanned with a HP Officejet J4580 and saved as png file. In the HP software there is also the the option to invert it. (Purpose of this is off course to have later my signature as watermark.)
Do I understand correctly you were able to use the ABC.png as watermark in Lightroom without crash after you changed it ? Can you copy this file in the dropbox ? Not sure where I can set up the color profile for the HP printer (scanner) :-(
I opened and resaved the PNG with Photoshop and it didn't crash LR, so it seems your scanner is producing PNGs that aren't quite compatible with Lightroom.
Instead of me uploading files after editing in Photoshop, you can use an online editor like Pixlr to edit your own PNGs that won't crash Lightroom:
I used the following steps in Pixlr to convert ABC.png to a transparent background PNG that had black writing then another with white writing:
- Open apps.pixlr.com/editor/ Online Photo Editor | Pixlr Editor | Autodesk Pixlr in a browser, I used IE 11
- Click Open Image from Computer
- Browse to and Open ABC.png
- Double click the padlock symbol in the Layers panel to convert Background to Layer 0
- Select the Magic Wand tool - over at the left
- Turn off Anti-Alias and Contiguous checkboxes up top if necessary because you want all the background removed and clean edges on this B/W PNG
- Click on a white area outside of the letters, notice that the insides of the A and B are also selected because Continuous is turned off
- Hit the Delete (Del) key, notice that the background turns from white to a checkerboard pattern indicating transparency
- Use File / Save... and save this black-letter copy with a new name (e.g. ABC_black.png) to your computer, somewhere, as filetype PNG - Transparent, Full-Quality
- Use Adjustment / Invert to change the letters to white, notice that the transparency remains
- Use File / Save... and save this white-letter copy with a new name (e.g. ABC_white.png).
Obviously you can do more things in this editor, but for the simple task of making transparent background PNGs from a scanned PNG that's all you need to do.
Magic. It works ! Many thanks