i) A 220 sized rollfilm basically consists of three parts:
- a paper leader (of 120 paper sized width - x) and having length 'A'; followed by
- a length of film emulsion (of 120 film sized width - y) and having length 'B'; followed by
- a paper trailer (of 120 paper sized width - x) and having length 'C';
ii) The rollfilm is wound, during manufacture, onto a normal 120 sized spool in the order trailer - film - leader.
iii) One end of the length of film is adhered to the end of the paper leader and the other end of the length of film is adhered to the start of the paper trailer; this is usually accomplished by using a suitable length of adhesive tape; at both its ends, the film should overlap the paper leader/trailer by a few millimeters and be afixed to the inside radius of curvature of the paper so you have in effect a three layered sandwich over the short length where the film is fixed to the paper consisting of paper, film and tape as we go from the outside of the wound reel to the inside. The adhesive tape need not span the whole width of the paper leader but should have a width that is sufficient to ensure that the joint does not tear apart during the film winding operation. The non film ends of the leader/trailer papers may be shaped into tongues in order to engage with the slots in the reels.
iv) The film should be taped to leader/trailer papers such that it is centred and all lengthwise edges are parallel; as this has to be done in total darkness, some practice may be necessary - but it is not difficult.
v) Typical lengths are:
- 'A' 21 inches
- 'B' 60 inches
- 'C' 13 inches
- y 60.5 millimeteres
- x 61.5 millimetres
These lengths do exhibit some variations especially 'A', 'B' and 'C' but they work for me on Hasselblad A24/A32 backs. You may wish to experiment to determine what is best for your setup.
vi) In addition, there is the need for a "start mark" which is to be put on the outer surface of the leader paper; this usually consists of a thick line across the width of the leader paper; it should be positioned about 7.5 inches from the start of the film. This is used to align the film to film advance/counting mechanism in your film magazine.
vii) You can prepare, trailer and leader papers in daylight but clearly the taping of film and the winding onto the spool must be done in total darkness. That is basically it. I would strongly recommend you to acquire then sacrifice a 220 roll film and to take it apart; the above would then become clearer in your mind and you could practice remaking the film in daylight and then with a blindfold possibly before you start rolling your own.
If you start with 70mm roll film you will see from the above that it is too wide - you need a film strip of width 60.5mm so you must remove a strip of about 9mm along one whole length of your 220 film strip to be; alternately, you could remove about 4.5mm from along both whole lengths of your 220 film strip to be. If you are starting from unperforated 70mm stock, the former would be sufficient; if your 70mm stock is perforated, then the latter is more elegant but you will still probably have some residual traces of perforation along the length of your 220 strip.
That is why unperforated film is more suitable for this job; of course you could remove the 9mm strip along one length of the 70mm strip and take the remaining perforations on the other length into account when photographing - these perforations might encroach into your image area.
You need to remove the excess film using a film slitter which can be bought over the web for about 30 US dollars.
Since the actual image area is typically 56mm by 56mm, there is scope to make your 220 film strip even narrower; this however may lead to further problems such as difficulty in centering the film strip relative to the trailer/leader backing papers and the fact that your strip may now be too narrow to be able to be held securely in a typical developing tank reel.
Is it practical? Yes of course it is; when you have rolled a few of your own, you will become proficient and enjoy the benefits of shooting longer rolls of film (if that is what you want to do).
Is it cost effective? That is impossible to answer because there is no longer any commercially produced 220 b/w film available with which to make a comparison. It has to be a subjective decision on your part. Personallly it is right for me and I have been doing it for years. Before this year's ULF run, I cut my own backing paper from 50 foot long, 25 inch wide rolls. I no longer have to do this and if Ilford were to offer in the future long rolls of standard 120 sized film (which they must have anyway) then the process becomes even easier.
Hope this helps,
Richard Hughes.