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X-ray Film Processing ISO400

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Proud Mary

Fri Oct 30 2009, 07:08PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

HP5 400 ISO 4" x 5" is to be used for x-radiography in a dark slide configuration.

Step by step, minute by minute, and centrigrade by centrigrade, what chemicals will be needed
to produce the best results for trial experiments to produce stabilized images?

Thank you,

Harry.

Steve Conner

Sat Oct 31 2009, 09:26AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

How long is a piece of string?

Joking aside, the process for developing black and white film is fairly standard. First you have to decide whether you want to develop it to the manufacturer's ISO rating, or "push" it to a higher rating. I'll only cover standard processing here. Push processing may well be useful to bring out faint X-ray images, but I've never done it, so you'll need to check out a photography textbook.

You'll need the following parts:

A really dark room with a tap and sink. If you can find a blackout bag (a bag made of heavy black cloth with hand holes, specially made for film handling) then the room doesn't need to be so dark.

A developing tank (might not be necessary if you just want to handle one small film piece)

Developer, stop bath and fixer, available as concentrates, but harder and harder to find as digital cameras stomp film to death.

A thermometer.

A stopclock or other timing device.

Start by making up the developer, stop bath and fixer solutions as per the instructions on the bottles. The temperature of the developer is important, because the developing time is a strong function of it. You should get a developing time vs. temperature chart with the developer, but you want it to be about 20 degrees. Tap water can be much colder in the winter, so add warm water as needed.

Now load the film into the tank in complete darkness. This takes some practice, so it's a really good idea to practice with scrap film first. If you're only doing one frame, you may be able to do it in dishes, but total darkness is even more important without the extra protection of a lightproof tank.

Once the tank is loaded and closed up, you can turn the lights on. Pour the developer in, bang it on the table a couple of times to dislodge air bubbles, start the clock, and agitate as per the instructions you got with the developer. Agitate doesn't mean violent shaking, as this causes air bubbles and reduces contrast. Just gently turn the tank upside down and the right way up again.

Once time is up, pour the developer out and the stop bath in, and agitate continuously. The purpose of stop bath is to neutralize the developer, which doesn't take long. I forget the exact time, but it should say on the stop bath bottle. If I remember right, stop bath is just a dilute solution of acetic acid.

Now pour the stop bath out and the fixer in. Fixer gets rid of all the undeveloped silver, and by the end of the fixing process, the film won't be light sensitive any more. But for now it's still sensitive, so don't open the tank yet! Fixer is quite expensive, but you can reuse it several times. Used fixer contains silver compounds, and big photographic labs will recycle it to extract the silver. It also smells strongly of sulphur, so try not to spill it on your clothes.

Once the fixing is done, you can open up the tank. Or finally turn the lights on, if you're using dishes. But you're not quite finished yet. If you want a long-lasting result, the film must be washed under running water for about half an hour to remove every last trace of fixer.

All of this was much more laborious than sticking a memory card into a laptop, but somehow quite fun

rp181

Sat Oct 31 2009, 05:11PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

I would also like to add that after the film is rinsed with water after the fixer, their are compounds (the one I know of is Photoflo) that the film is placed in, then taken out and hung to dry, without rinsing with water. This gives cleaner film.

"A really Dark room" may not suffice, my school has a dark room, with a dark closet in it to open film, but even that causes the film to be exposed some sometimes. I would go with the bag.

Stop bath is about 30 seconds, constant agitation.

Also, don't mix the fixer and developer, it makes something (I forgot what, I think ammonia) and smells horrible. Some people are sensitive to the chemicals too, so be aware of that. I always use my bare hands though.

plazmatron

Sun Nov 01 2009, 06:39PM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

The most important thing, especially with "unkowns" like homemade x-ray machines, is documenting what you have done, in terms of exposure time, and subsequent developing conditions, and working from there.

Not one radiograph I ever took, was thrown away for this reason, and was instead placed in a folder. A bunch of bad images is a valuable tool for refining your technique.

Developing times are worked out, simply by taking several radiographs of the same object, and varying the dev time. The opposite applies for working out exposure times. Once you have a folder full of film, you will be able to pick up any object lying around, and be able to say with confidence " ah that will need x-kVp, y-ma/sec z-time etc..."

Les

Fabio

Wed Nov 11 2009, 09:40AM

Registered Member #122 Joined: Fri Feb 10 2006, 12:55PM
Location: Milano Italy
Posts: 148

Where is my previous post????

anyway, i have a backup!

*********************************************

i played with X-rays many times and all of the informations given so far are good, i just add few notes:

A really Dark room" may not suffice,

True!
an ISO400 film is really sensitive to light (expecially if you overdevelop it), and even if all cracks and holes are covered, even the fluorescent tubes's afterglow will expose the film!
I suggest you turn off the lights few minutes before opening the container of the film to fade the afterglow and adapt your eyes to darkness (with adapted eyes you may find some other holes or faint light sources), is better if you the use a small wattage incandescent bulb instead of high flux fluorescent bulbs to avoid afterglow and to decrease the time adaptation of your eyes.

Just gently turn the tank upside down and the right way up again.

be careful of some developing tanks:
cheaper models have a rubber cap instead of a plastic threaded ones, you must press the center of cap when you close the tank to make some vacuum inside otherwise it will' not watertight; is better if you test it some times with water before using with chemicals!!!!!

and finally:
me and some my friend tried many photographic films/papers few years ago until we found a best solution:
we used a MACO GENIUS FILM inside an Xray intensifing cassette to obtain an excellent negative transparent image and we use a varicontrast paper to replicate it in positive and adjust the exposure.
The MACO GENIUS is a photolitographic film so is easily reperible in large, largest and exaggerated formats, is really cheap if compared to a large format plain photographic film, can be manipulated in a darkroom with red safelight, can be developed, stopped and fixed with the same chemicals used for photographic paper, temperature and time of baths aren't so critical and finally his contrast may be controlled by varying the concentration of the developer; you may get excellent results with minimal problems and minimal cost!

Ciao!
Fabio.

LutzH

Thu Nov 12 2009, 10:29PM

Registered Member #1721 Joined: Sat Sept 27 2008, 08:44PM
Location:
Posts: 136

Hello:

I do radiology for a living, so I would highly recommend using a cassette with screens, in part for reasons on which I will elaborate later. For now there are two basic types of screens inside of X-ray cassettes:

1. Regular (About 400 speed equivelent)
2. Detail (About 100 speed equivelent)

For most larger objects the reqular screens are great, due to geometric blurring and scatter etc., you will not get better pics with detail screens. If your object is delicate, small, or thin, then try to use detail screen cassettes. This is what they are designed for.

There are different type of screens inside of the cassettes, the most common ones use a rare earth phosphor to generate green light when exposed to X-rays, often Gadolinium Oxysulfide. The other type converts x-rays into blue light like the older Calcium Tungstenate ones. The key here is to match the screen light color, to the peak sensitivity of the film used. You can put sheets of photo printing paper into the cassette also, but it is much slower, but a whole lot cheaper than film! for this I would recomend high speed or regular screens.

My main reason for recomending cassettes and screens is radiation exposure!

The basic principal used in medicine reference radiation dose is "ALARA" it stands for: (As Low as Reasonably Achievable). This principal applies also for hobby use, yes officialy I should be tellling everyone not to mess with X-ray's period, and that they are very hazardous, and that X-ray's and ANY equipment capable of producing them, requires licensing just about everywhere on the planet. After telling folks this they will of course disassemble their equipment, and take it to the dump. Ya sure they will, just like a kid will throw away his ice cream bar when you tell him that it has sugar, and its bad for your teeth!

Sooooo back to reality, please folks lets observe basic safety measures, and lets not get so caught up in the design of our equipment that we forget this. Here are some very basic concepts, these represent a very basic starting point. I would strongly suggest that you go a little further, and do some research on your own. If you can manage even a basic understanding of the science involved, then all the better for your safety, and for the safety of others like your neighbors who live below in your appartment! If you are not careful then they could become unwilling participants in an experiment on the effects of ionizing radiation. This reasearch has already been done, and we do not need to repeat these tragic findings.

Starting Point:

Minimum Shielding (Based on Voltage to X-ray tube): 15-70KV use about 2 mm or 1/16"min.of lead. Use 3-4mm or about 1/8"min. for 70-120KV. For 120-250KV use about 6mm or 1/4" of lead. For 250KV+ find a large uninhabited field with a handy rock wall, and use a 25 meter or 100 foot extension chord, you get the idea :) Use layers for thicker shielding, to make a 4mm thick shield 4 x a 1mm sheet is better than a single 4mm sheet. Concrete can be substituted but testing is essential due to density variations in concretes. Remember X-ray tubes produce off axis X-rays so you need 360 shielding. Also high energy X-rays can be scattered by thick objects etc. so secondary radiation needs to be considered also.

Distance: The intensity of the radiation goes down with distance via the inverse square law, thus twice the distance from the source, and you have about 1/4 of the radiation.

Time: Restrict the tube on time to only what is needed for the experiment.

System Speed: The faster your receptor the lower the hazard.

The screen material can also be used to measure high intensity radiation, you cut out a piece and attach it to a silicon solar cell, this could even be used to make an electronic auto exposure device.

X-rays can be a lot of fun, but they demand respect just like the high voltage which helps create them. One last note of warning reference X-ray tubes with Beryllium windows:

These tubes emit massive amounts of soft X-rays, a second of close range exposure to a diffraction X-ray tube for example at full power, can deliver a dose high enough to permanently remove the exposed skin. Skin grafts are very painful, in addition to the cancer which will show up later. So if you have to use a Beryllium window tube, permanently mount a .5mm Aluminum filter on the tube port. This will remove only the soft X-rays which do not contribute to your image anyway. So have fun, but be safe :) We want to oogle your results, and not grieve your passing. Take care and good luck....Lutz :)

Proud Mary

Sat Nov 14 2009, 07:54PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

An excellent and well informed post - Stella,

King Edward VII Hospital for Sick Officers (Wish Day Ward)

Fabio

Sun Nov 15 2009, 05:07PM

Registered Member #122 Joined: Fri Feb 10 2006, 12:55PM
Location: Milano Italy
Posts: 148

i do my experiments in a basement, i always pointed the primary beam on the floor or on a perimetral wall to ensure an enormous beamstopper; i always remotely operated the machine in another room behind at least one bricks wall for shielding me against secondary and scattered radiations; luckily, wood and plasterboard aren't common materials for home buildings in Italy (except few estetical parts) so i have bricks and concrete slabs everywere.

i point your attention to photo paper and intensifier cassette again:

with a KODAK TMAX400 photo film (similar to ILFORD HP5) i made these images (three different exposure times:

with the same film plus a reprint on a variable contrast photo paper this other image:

This is the result with Xray medical film inside an Xray medical cassette

and finally, what you see is what you can made with photolitographic film inside a medical cassette + reprint on photo paper..... even photo paper inside a cassette will made similar results (but of course in negative!), no doubt, this procedure gave the best results:

so, don't wait any longer, is time to

then

then scan it an save the pics on your

and finally, upload the results here!

Ciao!
Fabio.

Proud Mary

Sun Nov 15 2009, 06:31PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Thank you, Fabio, for your insights that always seem to put the rest of our X-ray enthusiasts to shame!

All my tubes are of the XRF type - beryllium end windows with HT+ connected to Earth.

I am doing a hospital-based PTSD /PIE program right now, but hope to put up a thread about my crystalography experimnts in the new year.

Stella

Fabio

Sun Nov 15 2009, 09:22PM

Registered Member #122 Joined: Fri Feb 10 2006, 12:55PM
Location: Milano Italy
Posts: 148

Hi Stella!

I suggest you to imediately start your experiments.
doing something exciting and nice can help you to not think your problem and finally...... make a better and faster healing.

I think that this can be considered a sort of radiotherapy, but without the exposure of your body and without any side effect so, in short, i want see some of your radiograms!!!

Ciao!
Fabio.

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