Thodoris, you said it is double sided X-ray film - with tube processing, one side of the film is against the inside of the tube. How is that side getting developer to it? I am confused.
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Thodoris, you said it is double sided X-ray film - with tube processing, one side of the film is against the inside of the tube. How is that side getting developer to it? I am confused.
Randy, it has to do with the diameter of the tube.Quote:
Originally Posted by Randy
For each format you have to use the "right" diameter, so that the film curls inside the tube in such a way as to not being pushed completely flat against the wall of the tube.
The 18cm dimension of the films I'm using has the right amount of tension/freedom inside a tube with a 3" diameter.
This allows for the chemistry to reach both sides of the film.
Thodoris,
OK, that almost makes sense to me - but at some point the outer side of the curled sheet of film has to make contact with the tube...doesn't it? The curled sheet of film can't just be suspended inside the tube, not making contact anywhere. In my minds eye I am trying to picture how the film could be suspended inside the tube allowing both sides to get even development - and the only way I can imagine that working is if the only part of the sheet of film that is in contact with the tube is the very edges. Is that correct? Sorry if I am just not understanding.
Thanks for your input - and I really like the image - reminds me of one I shot a few years back on regular 5X7 film.
https://www.dropbox.com/s/ljpwkgh5552is56/rh5.jpg?dl=1
Randy, I can't be 100% sure of what goes on inside the tube during processing, since the tube is closed.
My comment on how this whole thing works is an extrapolation from the results I'm getting, plus how the film fits the tube when I load it in (while still dry.)
I imagine that the tension I described above which keeps the film's back from total contact with the wall when I load it, remains to some degree even after the film gets wet.
It's possible that the flow of chemicals is not the same on both sides, but there seems to be enough of a flow of liquids on the back to produce evenly developed negatives.
Again, this is only a guess.
And, I like your picture too :)
Rapidrob,
Thank you for sharing your experience with us.
You've packed so much great information in your post, I saved it for future reference.
I'd like to offer a couple of notes though.
First, for anyone new to xray (or who's reading this thread thinking of giving xray film a try at some point):
If you were to develop xray film as it was intended by its manufacturer (rapid developer at 100-105 degreed F for 25 to 60 seconds), you would get a characteristic curve like the ones shown in the data sheets published by each manufacturer (do a google search for the film you're interested in using, and you'll find a pdf of that data sheet.)
Those curves are extremely steep for pictorial use.
That is why most people who use xray film for in-camera negatives are using dilute developers at lower temperatures, making their own tests to determine length of development depending on whether they intent to contact print (and with which process) or scan their negatives.
Second, regarding safelight testing:
The process you describe is fine, if you'll be processing the film in some sort of daylight processor.
In my experience, if you intent to process in open trays, it leads to about 12min of safelight exposure (1-2min prewash, 8min or so of developing, and 1min rinse before the film reaches the fix, plus 1min or so for loading/unloading before processing starts).
For such a working process, the safelight testing described by Kodak in the link below is more appropriate:
http://wwwca.kodak.com/global/en/con...Safelite.shtml
As long as we are talking processing.
This is for new folk. Old news.
I use KODAK only Film Hangers for DIY GAS Burst of CARESTREAM EKTASCAN B/RA SINGLE EMULSION VIDEO FILM. Kodak hangers have more drain holes.
I load 4- 8X10 or 8-5X7 or 16- 4X5 on 4 hangers into 1-gallon tanks, cover the tank and run through 4 different tanks in a row. I turn on white lights and relax between tanks.
Gas Burst Rodinol, still water stop, Gas Burst TF5. Last tank is bottom-up trickle wash. Times vary. Rodinol is 1/100. One shot. I reuse TF5. TF5 is made with distilled water. All temps 68F.
Remove and hang dry with no fan. Works for me.
This was with Lake Michigan water. No squeegee, no soap.
I am still setting it back up for rural water. This water is a little chunky. I have filters.
Save your X-Ray cutoffs for Fixer checking. Time to clear.
Thodoris, I am going to speculate that your method will work best on 4X5, work with 5X7 (13X18), but may not work at all with 8X10...which is what I shoot.
As we know, a larger sheet of film is more flexible than a smaller sheet of film, even if they are of the same thickness. A 5X7 sheet will not sag as much in the center as an 8X10 sheet.
RATS!
But, I may try fabricating a tube to try anyway.
Randy, according to my research, the 3" tube is the recommended size for 8x10.
The format I'm most interest in at the moment is 18x24cm (the European equivalent) and I have developed a few sheets in the 3" tubes with great results.
For 5x7 (13x18) the recommendation is 2" tubes, but my first attempt in that size was unsuccessful due to leakage problems. I might try fixing this issue at some point, but since I already made a couple of 3" tubes for 13x18 that work, I might not.
As a side note, I initially tried developing 2 sheets of 13x18cm in the tubes I made for 18x24cm, but one of the negatives moved during development and covered a bit of the other.
To fix this, I cut one of the tubes for 18x24 in half and glued between the two pieces a coupling.
The stopper that I mentioned that these couplings have in their middle, was exactly what was needed to keep the two films separated.
Hope this helps.
It does help - thanks. I will look into the 3" tubes. If you get a chance, perhaps post a picture of your tube assembly some time - or if there is one already posted somewhere, can you direct me to it. Thanks.
Randy, sure, I'll take a couple of pictures and post them here soon.
By the way, I'd like to make clear that all the posts I made about "my tubes" were only meant as clarifications. I was only trying to answer questions asked, as best I could. They should not be misconstrued as advertisement for this processing method.
I'm still in testing mode, as I've only processed about 20 sheets so far. It's too early to tell if it works consistently.
(Also, I'm not the first to have used this method. This is a diy version of the btzs tubes.
The only reason I didn't just buy a set of btzs tubes is because they cost too much to get them here in Cyprus. When you add shipping and taxes (we pay taxes on the shipping too…) they end up costing almost as much as a used Jodo expert drum.)
And even if I decide that it indeed works (for me), this method has a major disadvantage to others, like the gas burst that Randy Moe mentioned above. It's not productive. You can only process one sheet per tube, and each tube requires about 40"sec between lifting it from the rollers and putting it back on them with the next chemical.
This limits the number of tubes you can run together, while keeping your processing times consistent. It's more comparable to tray processing individual sheets.
On the plus side, they cost relatively little to make, so (in theory) you could load several and process them sequentially, without wasting time washing and drying tubes between processing cycles.
In any case, I'll keep on posting results as they come in.