Use of X-ray film: technical discussion with example images

[Eugen Mezei]

I have bought some 18x24 cm and 24x30 cm. Will this fit without problems in our casettes? (And in which ones? Metric system or inch?) Or are they nomimal sizes for the X-ray casettes?

I also bought some dental panorama film. It came in two sizes (same film) 15x30 cm and 12,7x30,5 cm (this one has mentioned in paranthesis: 5x12 in.). So it seems imperial and cm sizes were made.

[Daniel Unkefer]

Eugen,

Any 18cmx24cm holder (Fidelity, Lisco, etc) should work with your 18x24 film. Don't know about the other sizes. Arca Swiss made very cool film holders in the day

Sinar Norma 18x24 Lisco Holders by Nokton48, on Flickr

Sinar Norma 18x24 Lisco Holders XRAY by Nokton48, on Flickr

I'm a Sinar Norma collector and user (I guess!) and I found these cool Sinar Norma holders in a European auction site. They were not as expensive as some since they had no slides with them. Luckily Catlabs stocks these replacement slides so I am good to go. Kodak 18x24cm MINR seems to what is available, most of mine has come from France. Fits perfectly

[abruzzi]

Quick question--I've found that the red LED bulb I use as a safelight will quickly fog the Fuji HR-U. I have an old traditional safelight, but its so dar it takes me 5 minutes before I can see anything, and then only barely. I ordered some rubylith (actual Ulano brand) with the idea that I cut out a disk to cover the metal reflecting dish over the LED bulb, then a little black gaffer tape to seal the edges. That should be sufficient to remove whatever is fogging the film, right? Or should I do a double layer? (I'm trying to retain a resonable amount of brightness, with the other safelight, I might as well do it in the dark...)

[jmdavis]

I use a 7w red incandescent darkroom bulb at around 6 feet from the sink. Yes, it takes some time to get used to it. Can you put your led system on a dimmer? Do you know what light wavelengths it produces? But it is entirely possible to develop by inspection. You could look for the bulbs used by x-ray processing rooms too. I don't take a real look at the film until around the 5 minute mark. Fuji UM-MA development has been running around 6-6.5 minutes depending on water temp with Pyrocat-HD 1:1:100.

[Jim Noel]

Your red LED is not pure red. There are such available but you have to search.

[abruzzi]

Your red LED is not pure red. There are such available but you have to search.

I get that, but I’m hoping putting rubylith on it will tame it. As is, it works perfectly (5 minute penny test) on Ilford paper, but it burns the film with less that 30 seconds exposure.

[abruzzi]

I use a 7w red incandescent darkroom bulb at around 6 feet from the sink. Yes, it takes some time to get used to it. Can you put your led system on a dimmer? Do you know what light wavelengths it produces? But it is entirely possible to develop by inspection. You could look for the bulbs used by x-ray processing rooms too. I don't take a real look at the film until around the 5 minute mark. Fuji UM-MA development has been running around 6-6.5 minutes depending on water temp with Pyrocat-HD 1:1:100.

I’m not sure on the dimmer, but most LEDs don’t work with dimmers. This is the light I’m using:

https://www.superbrightleds.com/more...27-lumens/440/

It claims the light is 631nm, but I haven’t seen a sensitivity chart for the X-ray films.

[Corran]

Two things. First, many of us are using that exact LED light, but not getting fogging. The only fogging I've ever had was from a traditional safelight too close to the film. I'm not sure what could be causing the issue unless some kind of change in manufacturing happened or a defect in the bulb? I have two about 5 feet over the trays and haven't had a problem.

Secondly, I would suggest not using gaff tape or other items on the LED bulb as some bulbs can get very hot. It's usually high-output bulbs that get dangerously hot but better safe than sorry.

[jmdavis]

Fuji UM-MA film appears to be sensitive at 630nm. See post #5580 on this thread for a chart. I think that you want something between 580-610nm or so. I don't know the wavelength of my delta-jr 7w bulb but I didn't detecting fogging with it.

https://www.largeformatphotography.i...images/page558

[abruzzi]

Two things. First, many of us are using that exact LED light, but not getting fogging. The only fogging I've ever had was from a traditional safelight too close to the film. I'm not sure what could be causing the issue unless some kind of change in manufacturing happened or a defect in the bulb? I have two about 5 feet over the trays and haven't had a problem.

Secondly, I would suggest not using gaff tape or other items on the LED bulb as some bulbs can get very hot. It's usually high-output bulbs that get dangerously hot but better safe than sorry.

My bulb is about 6 ft from the work space in a simple metal domed light clamp pointed away from the work area that looks like this:



I wouldn't be taping the rubylith to the bulb itself, but to the perimeter of the metal dish.