Scanning - Copying Color Negatives with your Camera? White balance the orange mask.

Updated techniques

High end phones have very good cameras, the results are usable.
You may need a macro lens adapter to fill the screen with your negative.

• LIGHT BOX: How to scan photo negatives with your smartphone

Invert colours with Helmut

• HELMUT Film Scanner – Android Apps on Google Play
• Helmut Turns Your Smartphone Into the World's Fastest Film Scanner
• HelmutApp | Flickr

Bit of pipe holder for film and smartphone: 

• DIY: A Cheap and Effective Rig for Digitizing Negatives Using a Smartphone
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Using the  Epson V350 scanner for slides, negatives and photos.

• 1 minute per image! 
• drivers 
• howtoscan.ca ScanSlidesNegativesPhotosEbook.pdf to download with free subscription
• negative image size settings