Holder for 110 negatives (for a SilverCrest SND 3600 A2)

Some time ago I started digitizing my negatives (35mm).

I have 2 scanners for this purpose (of which the SilverCrest is the fastest, but also the lesser in quality).
As I also have a lot of 110 negative strips, the idea was born to create a holder for one of my scanners.
My other scanner (an Acer Scanwit) has a very dedicated interface in which you can scan exactly 6 negatives in a fixed holder. Creating a holder for 110 negatives for this scanner seemed impossible. I therefore decided to create a holder for the SilverCrest. For this scanner the holder must be inserted and progressed manually.

As you can see by the pictures and scad files I've added, I had some problems getting a decent picture.
The first version (scad and stl files with V0.1) was a good fit for the negatives and for the scanner. The problem was that I was getting a black picture. This is due to the auto white balance correction of the scanner. The plastic of the holder was displayed as pure white and therefor the image on the negative was black (see picture).
Before creating the second version, I drilled some holes in the holder, just to see if that would help (the light getting through the holes would be displayed as black, which I hoped would fool the auto white balance correction). This indeed help a bit (see pictures). Thus I created the second version (scad and stl files with V0.2).
As this version still did not let enough light trough to fool the auto white balance correction, I created another version (scad and stl files with V1.0). This version finally was good enough to fool the white balance correction of the scanner enough to create acceptable pictures from negatives.

I got the best results by starting the 'acquire' cycle for every negative. Somehow the scanner is then efficiently re-triggered to create a decent picture (color and contrast).
In the mean time I successfully scanned 6 rolls of negatives (25 each). It does take some work after the scan (clipping and color/contrast adjustment), but the results are satisfactory.

Enjoy!