Fresh New Kodak Disc Film

Hèrm Hofmeyer, The Netherlands, August 24, 2020

Why fresh new disc film?

It is well known that the size of disc negatives was thought to be too small to yield good prints, even for standard print sizes. On the other hand, it is surprising to see how well current high-quality disc scans perform. Nevertheless, disc is certainly not a format that quickly comes to mind when thinking of a format to resurrect, due to its low resolution, and for the fact that is relatively difficult to produce. However, some people have feelings of nostalgia (regardless the low quality), and the complex character of the production may be seen as an interesting challenge.

Original disc processing and printing

Surprisingly, almost no information can be found on how disc film was processed and printed originally, at least not on the internet. An easily found Kodakery February 3, 1982, gives some information on the developments involved, but does not list actual equipment. A presumably very interesting publication "K-17 Planning Your Disc Photofinishing Work Flow" exists, but could not be found so far. Luckily, the Kodak Photographic Products Reference Guide 8/83 provides a nice overview of the equipment needed, and a small-scale and large-scale work flow can easily be imagined out of this information. An interesting (Dutch) website exists on the daily business in a Kodak lab (> 100 employees) in The Netherlands. It also shows a Kodak 2610 disc printer.

It can quite often be read that labs did not buy dedicated 6-element lenses for disc printing, but if so many dedicated and thus expensive parts were needed anyway to print discs, as listed in the guide, what would have been the problem of buying such lenses? And what (3-element) lenses were used instead? As disc negatives were among the smallest, have enlargement lenses been used for their normal 3R prints, e.g. lenses normally used to make a large print from 110 film negatives?

Fresh new disc film project 2012-2013

In 2012, Hèrm Hofmeyer (The Netherlands) and Greg Miller (Film Rescue International (FRI), Canada) came up with a plan to produce fresh disc film. FRI provided professional advice, materials like film sheets, disc cartridges and hubs, and processing, scanning, and printing facilities. On June 17, 2012, the first two fresh B&W disc films were made by Hèrm Hofmeyer in The Netherlands, following a process similar to the one described in the fresh disc manufacturing protocol below. Some pictures came out surprisingly well, while others were useless due to severe stains of the cyanoacrylate based glue involved.

Results and further plans were discussed at the FRI boot at Photokina 2012 in Köln, Germany. November 11, 2012, the first three colour discs were produced, using fresh Kodak Porta 160 film. Results were successful and reassuring grainy, and between March and August 2013 not less than about 30 colour discs were manufactured for personal use. Below some scans of the fresh disc films can be seen.

Further information

No fresh discs are left from the project, but you can make some yourself via the manufacturing protocol below, published here first in August, 2020. For specific questions related to the details of the protocol please contact Hèrm Hofmeyer (herm_hof[at]gmail.com, remove the underscore), and for information on high quality processing, scanning, and printing of disc film, contact FRI (mail[at]film_rescue.com, remove the underscore).

How to make your fresh discs at home

Probably, there are many different methods to make fresh disc film, and of course not any of the following steps need to be followed exactly. However, the protocol below has an advantage: it has shown to produce correctly working fresh disc films. So it is suggested to start following the protocol exactly, then only afterwards to be modified to your own taste and preferences.

If you are in the need of cartridges and hubs, FRI may be willing to help, as they process many discs each cycle, for which naturally the cartridges have to be removed. More special, their very high quality disc scanning involves the detachment of the hubs too.

The cutting of the film is the most difficult and time consuming. One could imagine that a 3D printed steel punch can be made, with two interconnected 1 mm thick blades, following the outside and inside circumference of the disc respectively, and their edges filed sharp. Then it could be used, for instance with a hammer impact and a sheet on a cutting mat, to quickly produce excellent disc shapes. Another possibility could be the use of a laser cutter in a dark room, or maybe even covering the film with lightproof paper or foil and doing the cutting in the light?

Manufacturing protocol

Outside the darkroom: Print disc_template_v6.pdf using a laser printer, as some inkjet inks will not be visible in the darkroom. The disc_template_v6.pdf have been made by scanning a disc, importing it in Corel Designer 12, and drawing lines over the disc bitmap in order to get a line disc. Hereafter, the disc bitmap has been removed, the line disc has been copied and the two line discs have been moved on a rectangle exactly as large as the film sheet. If printed 100%, without scaling, the print is exact. Adjust circle cutter 1 (e.g. OLFA CMP-1/DX) for the inner disc circle on disc_template_v6.pdf, figure 1 (from here on all photos have been shot with a Canon 5D Mark II + EF24-105 f/4L IS USM, no disc film involved).

Then cut an inner circle in an old sheet and check whether it fits nicely on a hub (prepare the hub by breaking off the complete bottom hub ring; this is the ring without numbers), figure 2 and 3. Note that there is a very small extra ring on the hub between the upper hub ring and bottom hub ring, this very small extra ring is connected to the 5 small glue points. The disc inner circle should be slightly larger than this very small extra ring, in order to fit flat on the upper hub ring. Adjust circle cutter 1 if necessary. The reason to check this inner circle diameter so carefully is that it is very annoying after making several discs, to discover they won't glue to the hubs because they are slightly too small (or too large).

Adjust circle cutter 2 for the outer disc circle, using disc_template_v6.pdf, figure 4.

If wanted, this outer circle adjustment could also be checked with an old sheet and comparing the outer circle cut with an original Kodak disc. However, (very) small deviations of the outer disc circle diameter seem not to be critical. For extra confidence, also the paper discs from disc_template_v6.pdf could be cut now with circle cutter 1 and 2 and the paper versions could be checked with an original disc. Note that it is better for the inner disc circle to be slightly larger than to be slightly smaller. As mentioned earlier, if it is smaller, it is not possible to glue the disc to the hub. If it is larger, it can be centred visually during gluing. Using the needle of one of the circle cutters, punch EXACTLY (even a deviation of a half mm could be too much, getting 2 discs out of one sheet is very difficult) in each centre of the two paper discs on the template and cut out the rectangle sheet of the printed disc_template_v6.pdf, figure 5.

In the darkroom so far successfully an IR night goggle has been used (Yukon NVMT SPARTAN 1x24, 24124 with Compact Head Mount, without using its build-in light source, as this may emit also some visible red light) and a separate 940 nm light source (Kingbright BL0106-15-28), powered by a 6V battery. Note that the depth of field of this camera is quite shallow for the short focus distance used (between the eye and table), and only a single eye can be used. This makes the work in the dark room quite strenuous. If existing, two eye night goggles with a large depth of field at the required focus distance would be very helpful. In the darkroom: wear powder free gloves and align a sheet with the template paper, both the ink on the template and the emulsion side of the sheet should face toward you, with the template on top. This is because the outer holes and inner holes of the disc do not form a circle symmetric pattern and thus it matters how template and sheet are positioned. To avoid scratches, put baking (parchment, not backing) paper under the sheet, and put template, sheet, and baking paper on a cutting mat. If alignment is perfect, move the needle of one of the circle cutters carefully over the paper template, feeling the previous punched hole, and then push the needle into the sheet, making an indentation, figure 6.

Do the same for the other previous punched hole. Now remove the template, and move the needle of the outer circle cutter carefully over the sheet to find the indentation. It may help to change the orientation of the sheet towards the light, to see the indentation more easily. Once the needle is in the indentation, cut the outer circle, figure 7.

Do the same for the other disc. Now, using the inner circle cutter, follow the same procedure and cut the two inner circles of the disc, figure 8 and 9.

Take care that the disc is on the baking paper all the time to avoid scratches due to the cutting mat roughness (the cutting mat will get rough due to the cuts in it). Also, keep the emulsion side always towards you (so base side facing the cutting mat) so the indentation will be found much more easy. Of course, always the outer circles should be cut first, before the inner circles, because if first inner circles are cut first, the centre indentation is lost to make the second set of circles (which would then be the outer circles).

Outside the darkroom: using circle cutter 2 to cut the outer circles of the paper discs from the laser print of paper_template_v6.pdf, figure 10.

Then use circle cutter 1 to cut the inner circle of the paper discs, figure 11 and 12.

Inside the darkroom: wearing powder free gloves, put a paper disc with the black rectangles for the holes towards you on a sheet disc with the emulsion side towards you, figure 13.

The sequence of layers is now as follows (from your eye towards the table or cutting mat): your eye, paper disc with printed black rectangles as holes, paper disc back side (without printing), emulsion side disc, base side disc, cutting mat. Align the paper disc with the sheet disc carefully, and keep the paper and sheet disc surface more or less parallel to the light beam direction. Now use a hole puncher (like the DRAPER Expert 2.0-4.5 mm) to punch half holes of 3 mm on every black rectangle on the outer circle and the inner circle, figure 14.

Note that the above mentioned sequence of layers is critical: As mentioned earlier, the holes of inner and outer circle are not point symmetric, and this sequence of layers is needed (given the template_v6.pdf as it is) to assure the numbers on the hub are correctly visible in the camera window. If done, move away the paper, and check whether all holes are indeed half punched out the disc. If not, punch them again a little larger. If the punched hole is a little too much a circle, punch them again a little more towards the edge, because along the very edge, the hole should be open for 2.5 mm, figure 15.

Outside the dark room: Prepare hubs by breaking off the complete under ring; this is the ring without numbers. Mark one of the five small circles on the underside of the upper ring (these are coincident with the 5 glue spots) with a knife cut or paint dot, so they are better visible in the dark room, figure 16.

Put the hubs with numbers down on a piece of paper on the cover of a can or light safe box, put all the marked circles (with a cut or paint dot) in a certain direction (e.g. north). Prepare a slowly curing (1.5 to 2 hours, full strength after 10 hours) epoxy glue, e.g. "Bison KOMBI PRO XL" and apply -e.g. with a toothpick or likewise- some glue to the outer edge on the downside of the upper ring. In other words, the location where the sheet disc will touch the hub. Don't apply the glue too thin, as some thickness is needed to allow the glue to contact each part of sheet. On the other hand, don't apply it too thick as that will cause stains on the film during pressing the disc on the hub, figure 17. The glue needs to be slow curing, because time is needed to do all the preparing work, and it needs to be epoxy, because other glues may terribly destroy the film (like super-glue/cyanoacrylate). However, MS-Polymer seems to work though, and other glues not tried may work as well.

Inside the dark room: Start wearing powder free gloves, so any glue residues on your hands will not contact the sheet discs. Position the sheet discs -with the emulsion side facing towards you- on the hubs, aligning one of the holes along the disc inner ring with the mark on the hub, figure 18.

Now with only touching a left finger on the hub, use your right hand with a toothpick to press the disc inner circle edge on the hub. As the hub can always have some glue residues, use only one hand for fixing the hubs, and the other (with a toothpick) for pressing the discs on the hubs, figure 19.

Also use the toothpick only on the very edge of the inner circle. As it also will get contaminated with glue, touching other parts of the disc with it will stain the disc. Using a bird-eye's view, check all discs are centred correctly on the hubs. If not, it is possible to carefully shift them a little relative to the hub, the glue is not hardened yet. However, be careful on using clean gloves for the film. Then close the light safe box, figure 20, and let the glue harden for a day.

Outside the dark room: using a single cartridge, open the door of it. The door can be opened by first pressing with e.g. a toothpick in the hole at the backside of the cartridge (near the sliding race), then sliding the door open with the notch inside the race. Figure 21 shows a cartridge with the door open.

Check 1) Cartridge, important

Use an original Kodak disc, put it in each cartridge to be used and close the cartridge. Check whether the disc can rotate freely almost 360 degrees (from the locking position) anti-clockwise and clockwise with a half clothespin put into the driving hole, figure 22. It is normal that at one location, the locking position, the disc will not go further. Do not use excessive force during rotating the disc then, as then you will break a pin and the disc will not stop after 15 exposures anymore. Rotating anti clockwise (normal advancing) should go very easy as long as the door is open (which is the reason why the door was opened). It will be quite impossible if the door is closed. Rotating clockwise is theoretically impossible as a little pin is located in the cartridge avoiding the disc rotating clockwise and permitting rotation the disc rotating anticlockwise. This pin is located at the upper right corner of the inside of the bottom part of the cartridge. However, it is found in practice that rotation is quite well possible, only a small ticking noise can be heard. If the disc does not rotate completely easily counter clock wise and not reasonable easy clock wise (however here some resistance and ticking is allowed), the cartridge most probably has a bubbled up foil near the little pin (that avoids the disc rotation clockwise) and the cartridge should not be used.

Check 2) Fresh disc, optional

Inside the dark room: wear gloves. For each fresh disc a) insert the disc in the cartridge with open door, b) close the cartridge, c) check whether the disc can rotate freely almost 360 degrees (from the locking position) anti-clockwise and clockwise with a half clothespin put into the driving hole, figure 22. It is normal that at one location, the locking position, the disc will not go further. Do not use excessive force during rotating the disc then, as then you will break a pin and the disc will not stop after 15 exposures anymore. Rotating anti clockwise (normal advancing) should go very easy as long as the door is open (which is the reason why the door was opened). It will be quite impossible if the door is closed. Rotating clockwise is theoretically impossible as a little pin is located in the cartridge avoiding the disc rotating clockwise and permitting rotation the disc rotating anticlockwise. This pin is located at the upper right corner of the inside of the bottom part of the cartridge. However, it is found in practice that rotation is quite well possible, only a small ticking noise can be heard. If the disc does not rotate completely easily counter clock wise and not reasonable easy clock wise (however here some resistance and ticking is allowed), the disc should not be used, d) open the cartridge and check the next disc until all discs have been tested and selected.

Outside the darkroom: make some glue like for the hubs (slowly curing epoxy) and apply it with e.g a toothpick to the cartridges at the same points as where small fractures due to the previous opening have occurred, these spots seem to have been temperature "welded" or similar.

Inside the dark room: wear gloves and first put all discs in the cartridges without touching the cartridges to avoid glue traces going from the cartridges via the gloves to the discs later on. Now use one finger on a hub, not touching the disc sheet at any location to avoid possible glue traces, and check whether the hub is able to rotate and is positioned correctly, figure 23. If the door is closed, the disc will only rotate clockwise (with some ticking noises and possible some resistance). If the door is open, it will rotate anti-clockwise as well. Remember all the time what is the clean hand and what is the possible glue contaminated hand and use them wisely.

Close the cartridge (the exact hub/disc position is not yet important) and apply four wooden clothespins, one at every corner, figure 24. Let the glue harden for 24h and remove the clothespins.

Check 3, disc + cartridge combination, important

Finally, check again whether the disc can rotate freely by: a) open the cartridge door (in the darkroom of course!), b) check whether the disc can rotate freely almost 360 degrees (from the locking position) anti-clockwise and clockwise with a half clothespin put into the driving hole, figure 22. It is normal that at one location -the locking position- the disc will not go further. Do not use excessive force during rotating the disc then, as then you will break a pin and the disc will not stop after 15 exposures anymore, c) if all correct, turn it clockwise (looking at the disc label) as far as possible, until the locking position has been reached, d) close the door, e) be sure that the cartridge door has been closed by guiding the notch through the race again, but now in the opposite direction, figure 25, f) check the "number" window at the outside: it should read something between "1" and "x". Actually, this is often difficult to see inside the darkroom, but it is a check that could be done outside later on.

Now the cartridge can be given a new label, simply printed on a colour laser or inkjet printer and cut out.

Enjoy your proudly homemade discs!