sorry for late reply... fixing a lumen print is really up to you. It will change the look of the print and may take away some of the subtle shades, but if you want the print to be permanent then you have no alternative but to use fixer. Make sure to wash the print before fixing to ensure even processing, and afterwards to remove the fixer. If you're happy to tuck the print away in a dark box then it's fine not to use fix, but in light the print will keep changing as the paper fogs over time.
So, you didn't make the fixing step... Is it right?
sorry for late reply... fixing a lumen print is really up to you. It will change the look of the print and may take away some of the subtle shades, but if you want the print to be permanent then you have no alternative but to use fixer. Make sure to wash the print before fixing to ensure even processing, and afterwards to remove the fixer. If you're happy to tuck the print away in a dark box then it's fine not to use fix, but in light the print will keep changing as the paper fogs over time.