Actual pitch of 6x4.5 frames on 120 film?

[Cluster]

Hi, I've bought an old camera to play with and have a go with LoFi images on roll film.
The Halina 6-4 has an insert mask that allows it to change from 6x6 to 4x4. 4x4 seems to be a waste, I think that I could 3D print a new insert mask that will allow me to use more of the film.
The camera uses the standard backing numbering via two little windows.
When I played with roll film folding cameras in the past, one format was 6x4.5...
Is this measurement a nominal value, that is, is the 4.5cm the distance between the (16) frame numbers or the actual maximum possible frame width (so that the frame width plus rebate must fit within 4.5cm)?

 

[ChrisR]

I've got a roll of backing paper I keep for this sort of purpose... the frame to frame spacing size on this Ilford roll seems to be 46 mm (I think most 6x4.5 frames are slightly smaller than those nominal dimensions suggest). So if you use a 4x4 mask and select the 645 window you should be fine, albeit with a bit of extra spacing. You might also be able to play about with not quite winding on the full distance... but that gets very dodgy after the first frame! (I used this technique in my experiments with "in camera panos" using an Ikonta 6x6 camera).

 

[Cluster]

Thanks for measuring it.. It's not so that I can wind it on in any different manner, it will be transported as normal, from 16-on frame to frame marker.
I will make an insert for the camera which will mask down from 6x6 (nominal) to 4.5x6 and need to decide on what the frame gate width will be.
So, 46mm will be too much and cause overlap in some frames, maybe allow 3mm between frames at 46mm max, so the gap could be 43mm, I guess.
It might make a good starting point.

 

[David_Mug]

My 6x9 Super Ikonta has a clip-in mask to give 6x4.5 using two windows. The aperture in the mask is 43mm wide.

 

[David_Mug]

PS - Just remebered the RADA roll film back for my plate camera has a 6x4.5 mask. This one is 41mm wide.

 

[Cluster]

Great, thanks for the info.... i didn't say, but the camera has two film frame counter windows, 12 on and 16 on, so the winding is normal.
A small project for me, although I do remember from years ago, I quite like a square format.