Re: Use of X-ray film: technical discussion with example images
I like the x-ray film because it is orthochromatic, because its slow speed is good for lens cap exposures, and because it is cheap.
The double sided is a nuisance, but manageable. I always treat these like single sided sheet film, so the side of the film that faces the lens is treated as the emulsion side and is kept up in throughout development. You could notch it, but if you are used to darkroom work it should be simple to keep track since that side always stays up. As I learned from this thread, but worth repeating once in a while, develop in smooth bottomed trays - no ribs or troughs of any kind. Lift the film a few times during development to avoid blotchiness in the backside emulsion. If you have the space, you can run two developer trays side by side to speed things up. I've done three developer trays at a time with 11x14, but that was a handful.
I believe these are just two identical emulsions; the sides aren't marked and you can put it in the holder either way. As has been explained in this thread, the blue and green designations refer to the way x-rays are exposed, but for our purpose it is just an indicator of the color sensitivity, with green being most like traditional orho film, and what most people use as far as I know. Somebody had posted links to charts of color sensitivity at one point.
Re: Use of X-ray film: technical discussion with example images
Quote:
Originally Posted by
pepeguitarra
I have read and I think, I have understood how the X-ray film works. I will mention what I know hoping that someone may correct me if I am wrong. Regular current film is panchromatic and has light sensitive silver emulsion on one side. They also place another emulsion (anti-halation) in the reverse. This is the layer that many remove by washing the film prior to development.
The X-ray film does not need to be panchromatic, so it is orthochromatic (like the old original films). They (Kodak and Fuji) place a light sensitive silver emulsion on one side, and maybe an anti-halation emulsion in the other side. However, the x-rays do not produce light to impress the sensitive emulsion. That is when the manufacturers, place another emulsion on the back of the film that react to the x-rays by ignition producing light during the reaction. That light is the one that is going to create the image on the silver emulsion. My thought is that that emulsion that reacts with the x-rays to produce light is also mixed with anti-halation. I am not sure if this emulsion gets washed with the pre-washed, it may be. I am pre-washing for 5 minutes the x-ray film. I have heard that some photographers scrap or remove the not needed emulsion. The problem for me would be identifying which one is the side holding the image. Any comments or enlightenment?
I'm not an expert, but I don't think that's right. The film is not exposed directly by x-rays. X-rays get emitted, pass through what they're imaging, and then hit a screen that glows in proportion to the x-rays that hit it. This screen either glows with green light or blue light, and that's what corresponds to the x-ray film being blue or green labelled. It's the glow from the screen that exposes the x-ray film. Both emulsions on a two sided x-ray film are the same, and they both respond to visible light, either blue or green (and perhaps more.) X-ray film is two sided since that leads to double the density, which is important when looking for flaws in bones.
Re: Use of X-ray film: technical discussion with example images
Peter is right. There is no magic emulsion on xray film. It's just a very basic blue-sensitive or orthochromatic emulsion with a very flimsy topcoat. Mammography film has only one emulsion side and a water-soluble dye-based anti-halation coating on the backside, while regular double sided film just has two normal emulsion layers, one on each side.
No conversion of xray to visible light occurs in the film itself and there is no appreciable capture of xray in the photographic emulsion or even the entire film itself.
Re: Use of X-ray film: technical discussion with example images
Quote:
Originally Posted by
Peter De Smidt
I'm not an expert, but I don't think that's right. The film is not exposed directly by x-rays. X-rays get emitted, pass through what they're imaging, and then hit a screen that glows in proportion to the x-rays that hit it. This screen either glows with green light or blue light, and that's what corresponds to the x-ray film being blue or green labelled. It's the glow from the screen that exposes the x-ray film. Both emulsions on a two sided x-ray film are the same, and they both respond to visible light, either blue or green (and perhaps more.) X-ray film is two sided since that leads to double the density, which is important when looking for flaws in bones.
Thank you Peter. That sounds more logical. Here is the film I am using, which is single coated: X-ray Film
Re: Use of X-ray film: technical discussion with example images
This is the film that is single coated with antihalation.
Quote:
Originally Posted by
pepeguitarra
Thank you Peter. That sounds more logical. Here is the film I am using, which is single coated:
X-ray Film
Re: Use of X-ray film: technical discussion with example images
Quote:
Originally Posted by
pepeguitarra
Thank you Peter. That sounds more logical. Here is the film I am using, which is single coated:
X-ray Film
Argh, wish I saw that earlier! Now I'm stuck with 100 sheets of double-sided green Fuji HR-U :)
I've learned about how X-Ray film works from this Instructable, interesting read:
https://www.instructables.com/id/Homemade-Xray-Machine/
Re: Use of X-ray film: technical discussion with example images
In the book THE IMMORTAL LIFE OF HENRIETTA LACKS, I learned that Mrs. Curie used to bring pieces of Radium in her pocket. She came from Europe in the plane with a bunch of rocks in the pocket. Then, they cut the patient open and place a piece of rock inside the body, close to the tumor. Months later, they open again remove the rock and check the reduction of the cancer tumor. That is how radiation started. She died of cancer, presumably caused by the handling of radioactive material in a really ignorante way.
Re: Use of X-ray film: technical discussion with example images
So I'm planning on using Rodinol for my Fuji HR-U developing. What should I use as fixer? Some people here mentioned using hardening fixer. Is that what everyone is using?
Re: Use of X-ray film: technical discussion with example images
Use whatever fixer you have.
I use TF5 mixed with distilled water, but fixer only must be fresh enough, meaning not exhausted.
Save exposed but not processed scraps of X-ray for testing 'clearing time'.
Re: Use of X-ray film: technical discussion with example images
Quote:
Originally Posted by
koraks
YMMV, but I find double-sided film noticeably less sharp than single sided. The scratching issue is what eventually turned me off double-sided film altogether; I'm not wasting money on it anymore. Too much hassle with very little benefit in return, if any at all.
Yes single sided is sharper, but you can't see that unless you do side by side comparisons. Personally I feel the double sided green is an excellent x-ray film. I'm not sure why you cannot process without scratches. How were you processing it?
