Digitising collections of microfiche - Re: Looking for opinions...

[Pete Turnbull]

On 29/03/2018 05:26, Shaun Halstead via cctalk wrote:

> Using the wrong filament orientation can cause some weird artifacts
> to appear on scanned images, because of the high magnification. I
> strongly suspect that an attempt using an LED source would face
> similar (and possibly worse) issues.

> Light source.  Due to lensing requirements, LED's are probably out, 
> unless a way can be found to suitably diffuse or blend the source 
> without losing significant light.  This requires a very strong light 
> source.

Yet there are plenty of LED light sources used in photomicroscopy so I
don't believe it's that hard to do,which is why I suggested it.  I've 
seen it done with a high-brightness 5mm LED, but if a bit more "oomph" 
or a larger emitting area is required, there are inexpensive 1W and 3W 
LEDs that look like they'd work.  I'm no expert, but the biggest problem 
in photomicroscopy seems to be the spectrum, which isn't really an issue 
for monochrome microfiche.

-- 
Pete
Pete Turnbull