Blue light for more sharpness? -Avoid diffraction?

[ForenSeil]

Hi
I wonder if it might be possible to get more resolution out of the same object with the same lens when using blue or better pure monochromic blue or violett light (maybe ~430nm?) instead of normal white light.
Theoretically blue light should cause slightly less diffraction because it has a shorter wavelength and monochromic light would cause a picture which is completly free of any CAs.
Of course a B/W conversion would be necessary afterwards.

My idea is to use blue light while digitalizing 35mm B/W negatives - they are monochrome anyway.

Does it make any sense for you?

Next question would be what to use as a monochromatic lightsource
Using a prism or a diffraction grating to make an own monochromatic light source would make it unreasonable laborious

EDIT: A 405nm 5mw laserpoint might be interesting as monochromic lightsource.

[kds315*]

How about a Royal blue LED? But you need a suitable method to get a very uniform distribution of that light and this is quite tricky.

[SXR_Mark]

If your imaging device uses a Bayer pattern sensor (like most digital cameras) you will lose resolution because you will only be using a quarter of the pixels in the sensor, i.e. those with a blue colour filter over them. With an ordinary camera you would be better using green illumination (Bayer pattern is 2 green to every 1 red and 1 blue pixel).

You can get de-Bayered sensors. Or buy the B&W Leica.

mark

[buerokratiehasser]

I have thought of screwing a sharp filter before the lens and just expose for like a minute.

The problem with this is of course that you need something like b/w Adox copy film 25 and insane lens for the mono to have any noticeable impact (e6 and c41 drop at 200lpmm or way below), hrmm .. you could maybe indeed stop down to f8 or f5.6 or so instead of 5.6 or 4.

The next problem is that it will look just weird because everything not blue will be black. Even some blues will be black when they aren't broadband enough.
It will look weird even if you use R,G,B filters (which isn't even practical because screwing them will jiggle your setup) in succession. You can get this effect cheaper by using e6 duplicate film.

[buerokratiehasser]

Oh yeah and if you go for 3 rgb exposures these will of course have CA shift which you'd need to fix in postprocess. Not that there is a postprocess that can scratch 20,000 dpi off your negative.

I'd just go buy a 645 or P6.

[Bille]

[ForenSeil]