High quality transparency

[jhphotography]

I have a scanned file of a signature created in blue ball point pen from which I want to create a PNG file of the signature without any background artifacts, but in spite of making numerous tries to create the file I want with the transparency eraser, the resultant files always have several spots of non-transparency, and transparency has not bween created with consistent closeness to the signature, creating an ugly result when the file is placed on top of anything that's not pure white. I'd appreciate suggestions on how to create the high quality PNG file I seek. Thanks!

[Mylenium · Accepted solution]

Image --> Calculations --> Transparency mask, then a few adjustments on the mask and exporting using the mask info.

Mylenium

[jhphotography]

Very helpful, Mylenium ... many thanks. https://www.redbubble.com/shop/ap/129206065