I was doing a series of scans from a Hagner sleeve, after having not used my scanner for a few weeks. The results were disappointing, as each scan seemed blurred and a little washed out.
I subscribe to the 'Standard' paid Vuescan service. I had both the 'preview' and 'scan' resolution set to 600 dpi, which should have produced very good quality results. Here's what I got:
Having cleaned the scanner's glass plate, there was no improvement. I was worried that there was something wrong with my Canon Lide210.
I then tried scanning using the standard Windows scanning software, selected from 'Control Panel: devices and printers'. Here's what I got:
Just as it should have been. So what was wrong?
I thought I should check through all the Vuescan settings... And there, under 'Filters', I had previously set the Descreen tick-box to 'on'. This is used when scanning a newspaper article or black and white photocopy. Which of course, I then remembered having done about a month before.
Having un-checked the box and rerun the scan, everything was back to normal. Panic over.
So the moral of this story is, check the software settings carefully, particularly if you experience 'senior' moments like me.