Blue Stain of X-Ray film

[sanking]

I have been experimenting with some of the green sensitive X-Ray film. After the film comes out of the fixer it has a very pronounced blue stain. I assume this stain is eliminated with standard processing because I have never seen a blue tinted X-Ray. Does anyone know what chemical is used to eliminate the stain?

Sandy

[Brian Bullen]

Sandy,

Are you sure it's a blue stain and not a blue base material? Taken from a kodak x-ray film pdf. "This film is coated on blue, 7-mil ESTAR Base with a base density
of approximately 0.18. KODAK Medical X-ray Film"
This might be what you're looking at, the blue color surprised me at first too.

[sanking]

Sandy,

Are you sure it's a blue stain and not a blue base material? Taken from a kodak x-ray film pdf. "This film is coated on blue, 7-mil ESTAR Base with a base density
of approximately 0.18. KODAK Medical X-ray Film"
This might be what you're looking at, the blue color surprised me at first too.

Brian,

I guess it could be the base material. I just assumed it was some type of stain because I have never seen any blue tinted x-rays.

Sandy

[Brian Bullen]

What type and brand are you using?

[sanking]

What type and brand are you using?

Agfa green sensitive film.

Sandy

[Brian Bullen]

I did a little google searching for agfa blue base x-ray film and found some references but nothing substantial, and their website mentions the "Cronex 10T has a cool blue tint designed to reduce eye fatigue." Hope this helps
http://www.agfa.com/en/he/products_services/prod_cat/index.jsp#Conventional%20Imaging%20&%20Processing

[SteveKarr]

Hi,
Most (not all) X Ray films are coated on blue plastic to reduce eye fatigue. (it also makes it look sexy on TV) There is one film I tried that was on a clear base. I can look it up soon.

I love X ray film for its gutsy look (like pushed Plus X) and how dirt cheap it is. But because it is coated 2 sides it scratches soooo easy.

Have fun!!

PS ... watch out for 1/2 blue, it is like 6 asa where the others stuff is about 100 asa... half my butt!

[Vaughn]

It is the Agfa Cronex 10T that I have (14x17). Definitely has a blue base.

Vaughn

[Mark Woods]

I use the CSX Green sensitive and it has a blue base too.

[sanking]

When I received the Agfa green sensitive X-Ray film the first thing I did before testing was to check to make sure that it was not sensitive to my red safelight. Since I planned to use the safelight in the cutting process about two feet from the cutting area any sensitivity would ruin the film. So I cut a piece of the film in complete darkness and then exposed it for two minutes about three inches from the red safelight, then fixed it.

It came out perfectly clear so I figured it is okay to develop the film with a red safelight about two feet from the tray. I did, but nothing worked right as every sheet I developed came out heavily fogged. Since I know that the film is not sensitive to red light I figured there must be some kind of incompatibility between the developer or the fixer that is causing the fogging. So I repeated the tests with different developers and fixers, with the same result, lots of fogging.

Then I asked myself, could the fogging be from the red safelight? I ran a test developing the film in complete darkness, and guess what. No fogging at all!!

Could someone explain this to me. The dry film has absolutely no sensitivity to my red safelight, but the film being processed develops sensitivity to it? I would not have thought this was possible until I tested it both ways.

Sandy King

[Jay DeFehr]

Sandy,

Did you try plain water under the safelight, then fix?

[sanking]

Sandy,

Did you try plain water under the safelight, then fix?

Jay,

Yes, I took the film from the developer and ran it through two separate water baths before fixing. With the red safelight on I got heavy fogging.

Repeating the experiment with the red safelight off, same procedures otherwise, no fogging.

Sandy

[Robert Hughes]

All the x-ray film I've seen lately has a blue stain, including the CVS green-sensitive stock I use on my 8x10.

[Jim Noel]

Sandy,
Is it possible that the film sensitivity to red increases when in the presence of a developing agent?

[SteveKarr]

Hey Sandy,
I too had the Red safelight Death problem. I found out that green & blue are exposed under red safelight of all but the weakest! strength. I also found out UV plays a part so no CFL's in the safelight housing.

You can buy an "X Ray film safe" filter from I bet B&H or get one from a closed X-ray lab with the proper notch for the film & be golden. It real is 100 speed film after all, so no Plus X in safelight.

Steve

[Jay DeFehr]

Sandy,

I meant, no developer, plain water, then fix. Then you would know whether the developer or fixer was sensitizing your film. The plain water would just be a kind of place holder, to keep processing times similar. I suppose there's the off chance that simply wetting could sensitize the film, too. Very interesting.

[sanking]

Sandy,

I meant, no developer, plain water, then fix. Then you would know whether the developer or fixer was sensitizing your film. The plain water would just be a kind of place holder, to keep processing times similar. I suppose there's the off chance that simply wetting could sensitize the film, too. Very interesting.

I have done enough permutations of the test now with chemistry and lights to be absolutely positive that the film fogs when I develop it with a red safelight at about five feet from the developing tray, and it does not fog when I develop it with the red safe light turned off.

It would never had passed my mind that the film could be insensitive to red light when dry but sensitive once it is in the developer. But I can not argue with the facts of what I have observed.

Sandy

[sanking]

A small correction. I wrote earlier that I was using the Agfa green sensitive film because I thought that was what I bought. I just looked at the film box again and it is the CSX brand green sensitive film, not Agfa.

Sandy

[BetterSense]

I develop CXS Green Latitude under my rather bright (but narrow-spectrum) red LED safelight. It has tested to be very tolerant to my particular safelight FWIW.

[Vaughn]

Sandy, I have experienced a hyper-sensitivity to pressure happening with silver gelatin paper after it is put into the developer -- for the first part of the developing, one can "expose" the silver with pressing the emulsion with tongs, etc. Even the pressure from griping a 16x20 sheet to flip it over in the tray can leave developed marks.

So changes in sensitivity does occur in some emulsions during development. Might be what you are experiencing.

[sanking]

I develop CXS Green Latitude under my rather bright (but narrow-spectrum) red LED safelight. It has tested to be very tolerant to my particular safelight FWIW.


Can you give me a source for this red LED safelight?

Sandy

[Jim Fitzgerald]

Sandy, I know we have discussed this but for me the answer to not fogging the film is to turn the safelight on when about 80% of the development time is passed. I've never had any problem with fogging. It is interesting that it does not fog until you get it wet either with developer or water?
My question is does the blue base affect the UV printing when we do carbon transfer? I'm not well versed on these matters. Does the blue base and yellow dichromate sensitizer cause any problems with exposure?

Jim

[sanking]

Sandy, I know we have discussed this but for me the answer to not fogging the film is to turn the safelight on when about 80% of the development time is passed. I've never had any problem with fogging. It is interesting that it does not fog until you get it wet either with developer or water?
My question is does the blue base affect the UV printing when we do carbon transfer? I'm not well versed on these matters. Does the blue base and yellow dichromate sensitizer cause any problems with exposure?

Jim

Jim,

I don't believe the blue base matters very much, if at all. I am getting a B+F reading of about log 0.20 with a densitometer in UV mode. I would expect an estar base of about 7 mil to read about log 0.05-0.08 so the blue color appears to be contributing about 1/2 stop of UV density to the B+F. That means it increases exposure by about 1/2 stop, but we would just print through it.

I did a BTZS type testing of the film today and my results are very close to the ones you have reported. That is, development of 7-9 minutes with a 1+1+150 dilution of Pyrocat-HD and constant agitation at 72F gives negatives about right for printing carbon . With these times my Dmax was 2.90 (7 mins), 3.15 (8 mins) and 3.40 (9 mins). In fact, the 8 minute time almost exactly matches the Dmax of my digital negatives. I have not actually made a print yet but the negatives at 7, 8 and 9 minutes have a long straight linear curve and they should in theory print well in carbon if you use a very strong sensitizer.

Sandy

[Mark Woods]

Hello Sandy, I had the same experience. I have a lot of calibrated filters for Cinematography, so I added a CC 90 Magenta (complimentary to green) to my safe lights and haven't had a problem since. I was surprised the same as you.

Good luck!

[Mark Woods]

When you squeeze the film, that's a stress exposure that has nothing to do with light.

I didn't think the blue would make much of a difference sine it should pass short wave lengths through it. Primary Blue is about 350nm, UVB is around 300nm. I thought it wouldn't affect my exposures in my UV light box, but it did. My PP exposures for normal pan negs is 7 to 9 minutes. With the Green X-Ray film I calculated my test that I would need to expose them for about an hour. I'm going to do more tests when I get some time. I'm putting together my lectures on S3D and motion picture digital work flow from acquisition to theater.

[BetterSense]

Can you give me a source for this red LED safelight?


I just put one of these...

http://www.dealextreme.com/details.dx/sku.1776

...on an old computer heatsink with an LM317 current source. I have two of them. They work well. There are places that sell red LED lamps that screw right into lightbulb sockets though, and I hear that red CFL lamps (you can get them at Fry's) work well too.

[Jim Fitzgerald]

Jim,

I don't believe the blue base matters very much, if at all. I am getting a B+F reading of about log 0.20 with a densitometer in UV mode. I would expect an estar base of about 7 mil to read about log 0.05-0.08 so the blue color appears to be contributing about 1/2 stop of UV density to the B+F. That means it increases exposure by about 1/2 stop, but we would just print through it.

I did a BTZS type testing of the film today and my results are very close to the ones you have reported. That is, development of 7-9 minutes with a 1+1+150 dilution and constant agitation at 72F gives negatives about right for printing carbon . With these times my Dmax was 2.90 (7 mins), 3.15 (8 mins) and 3.40 (9 mins). In fact, the 8 minute time almost exactly matches the Dmax of my digital negatives. I have not actually made a print yet but the negatives at 7, 8 and 9 minutes have a long straight linear curve and there is no reason I can see they would not print well.

Sandy

Sandy, this is awesome! Nice to know that it is only a half a stop. Nice to see the Dmax that you can get with this film. This is the same thing I have experienced. Please let me know how the pints come out. It is great to know that an alternative process like carbon can benefit from inexpensive x-ray film.

Jim

[desertrat]

There are red LEDs and then there are red LEDs. There are two or three different types that operate at different wavelengths. I posted this at APUG:

I bought a red LED PAR-30 lamp from an Ebay vendor to use with paper and X-ray film. It works great for paper, but fogged the film. It's very bright, almost like dim room light, and I guess it was too much to use continuously for the film. I've got it tamed down for film developing by hanging a piece of black plastic sheet in front of it. No problems with the film now.

I did some research, and there are several wavelengths available for red LEDs. One peaks around 630 nm and another around 660. Mine was 630. I'm thinking about buying an LED replacement automotive taillight bulb. I've seen some advertised as operating at 660 nm. I think the longer wavelength red would work better with the X-ray film. I discovered LEDs don't operate at a single wavelength. There is a certain amount of spread. The 660 nm LEDs seem to operate with a narrower bandwidth than the brighter 630 nm bulbs.

Found some info here:

http://www.oksolar.com/led/led_color_chart.htm

I think the 660 nm bulbs are described as "ultra red" on this chart.