Near Infra Red - Nikon D50 - What filter or technique to use?

Http://www.kenrockwell.com/nikon/d50ir.htm
"White Balance and color" images.
Image ref.nrs.:
12
34

The upper link takes you to a page where the camera used is supposedly the same as mine, yet the image is white/gray/blue/yellow while mine are of solid colour. The numbers above correspond to 4 photographs on that same page (about 1/3 slider down at White Balance and color section).

I use a home-modified Nikon D50 with 2 layers of black slide-film as IR filters instead of hot mirror on the chip.
My initial idea was that the second cover blocks too much visible light and renders images a solid colour - but this doesn't explain why White Balance doesn't work.

So my problem is this: I wish to make an image like #2 - the bluish leaves and brown clouds but always end up with a violet version of #1. I tried setting white balance manually with one of the blank page images I took but the pictures remain violet. I shoot in RAW(.NEF)

The other WB settings work. Or used to before I removed the hotmirror. I can still see the difference if I shoot with "flash" or "tungsten" but manual WB doesn't make it white. Could the image be "too violet" for the camera to process? Or is it the film's fault? I've got a glass IR filter (Cokin 89B) that gives much more red photographs, but would that really work differently?

I have a Canon 10D that has been professionally converted to record near infrared, so I'm not sure how this advice will work in your case. I tend to read a custom white balance from local foliage rather than a grey card, because foliage reflects a lot of infrared (e.g.point the camera at the grass, take a shot, set and set that as your custom balance).

Nonetheless, even with this method the results turn out looking very flat and monochome. Have a look at this post on Digital Photography Review, where I show some samples:
http://forums.dpreview.com/...e=36742621

You'll notice that they look a bit like Ken's, although the first image is less red, because I'm using a converted camera rather than filters. The problem, as far as I can see, is that neither the camera nor Photoshop's RAW module have enough range to map the colours properly. To fix this I load the image into Photoshop and select "auto color" from the image-adjustments menu, or "auto white balance" from the Colors->Auto menu if I'm using the GIMP, which is free. The result still needs a lot of contrast work and channel swapping.

However, I remember from using infrared filters on my Kodak DCS 560 that there often wasn't enough visible light to extract any colour information at all, without boosting the saturation so much that the noise was boosted as well. This could be your problem; it could be that your filter is passing no visible light, and that neither the camera nor your raw module nor your image editor can extract different colours from the resulting file. In that case you'll have to convert the image to black and white.

I can recommend getting your camera converted - Lifepixel seems to be the default choice in the United States, they even have a DIY guide for the D50:
http://www.lifepixel.com/ir-tutorials/nikon-d50-digital-infrared-conversion-instructions.htm