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Tim k
25-Apr-2011, 10:42
Does anyone care to voice an opinion as to which type of film seems to be working out better for general photography, or for high contrast applications such as carbon printing? Is there a type that seems to be rising to the surface, so to speak?

Thanks

Vaughn
25-Apr-2011, 11:26
And while we are at it,

What are the different qualities of the "Green" and "Blue" types?

Mark Woods
25-Apr-2011, 13:15
Hello Vaughn, I think you're talking about X-ray film? Do you mean the green sensitive v/s blue sensitive? And Tim, if you want contrast, the X-ray film developed in Dektol, or similar developer will give it to you quickly. I took Jim Fitzgerald's suggestion and use PMK for my 11x14 and D-76 for the other cameras in 4 gallon tanks.

Hope this helps.

Vaughn
25-Apr-2011, 13:25
My Agfa x-ray film is marked "Daylight", so I have not used any classified as green or blue like I have seen online.

I have been getting plenty of contrast using Ilford PQ Universal developer (1:9) -- will try one of the pyro developers "one of these days".

Vaughn

Heespharm
25-Apr-2011, 13:37
Check this thread:

http://www.largeformatphotography.info/forum/showthread.php?t=48099&page=36&highlight=Xray

Has information on the different types also ways to process it and such

Tim k
25-Apr-2011, 15:17
And while we are at it,

What are the different qualities of the "Green" and "Blue" types?

Vaughn, here is your answer;

5. What is the difference between blue and green sensitive film? Blue sensitive film is a 200-speed film that uses a blue emitting calcium tungstate phosphor screen for general-purpose radiography. Green sensitive film is a 400-speed film when used with a high efficiency green emitting gadolinium oxysulfide phosphor screen. Green sensitive film and screens use 50% less radiation than blue sensitive systems.

I copied it from here; http://www.sdssouthland.com/msdssharpimage.htm

Now if somebody could explain that to me? I'm good till about "200-speed". :eek:

Tim k
25-Apr-2011, 15:54
Heespharm, I have followed that thread. Thanks, there is a lot of good info there.

Vaughn
25-Apr-2011, 16:19
Tim, X-ray film , in its designed use, gets most of its exposure from the x-rays exciting a layer (and thus giving off light) behind the film in the film holder -- this layer then exposed the x-ray film... and not from the x-rays themselves. Think of it like the old black-light posters of the 60's and 70's, LOL!

I was interested if people have found the blue or the green better for general landscape work -- info I did not find in the other thread...but I might have just missed it.

My "daylight" x-ray film packaging mentions nothing about blue or green. In the sunlight, it seems to be as fast as 800ASA, but under the dense forest, its ASA drops dramatically -- and part of this may be due to a poor reciprosicity responce at longer exposures.

Vaughn

Tim k
25-Apr-2011, 16:46
I was interested if people have found the blue or the green better for general landscape work...

Vaughn

This was pretty much my question as well. I just asked in a more round-about confusing way. :)

Mark Woods
25-Apr-2011, 17:04
I use the green, but I've never tested the two different sensitivities side by side. If the film responds the way an electronic image does, the blue would not only be slower, but not a lot of natural scenes have a lot of blue in it -- except for the sky. Green on the other hand is in most colors at one level or another.

Tim Meisburger
25-Apr-2011, 17:43
Okay. If it doesn't exist already, it sounds like an interesting test. If someone that has both green and blue could shoot the same scene, or series of scenes, with each type at the appropriate ASA for each film, and perhaps a regular B&W film as well, then post the examples, that would be a definite contribution to the art and science of cheap LF.

Tim

Mark Woods
25-Apr-2011, 18:13
I agree with you Tim. Someone will have to buy both. Maybe we should take a collection to buy the emulsions. :-0 I could be wrong, but I think if we think about the sensitivity of the emulsion as being similar to adding a narrow band color filter in front of the lens, we'd have a pretty good idea of what the emulsion will represent.

Thoughts?

Lachlan 717
25-Apr-2011, 18:19
Perhaps a basic question, but are "regular" films the same dimension as X-ray films? That is, will X-ray 7x17 sheets fit my current "regular" holders?

If so, for the price of X-ray film relative to Ilford/Efke film, I'd buy a box of each and do some tests!

Then again, I'd probably chase up some Mammography film to try first.

Jim Fitzgerald
25-Apr-2011, 18:33
Guys, I'm sorry to be so negative with my following comments. Get a box of each and try it out already! It is so f'nig cheap just get some green like I did and shoot it at ISO 80 develop it in Pyrocat-HD in tanks or trays for 6 minutes and you are done. Then dry it and print it in carbon. It works great for me and I'm no wizard. Why did I pick green? Because I like the color!! My understanding is that the screens that they use it the x-ray world give it its sensitivity. Why are we trying to analyze this. It works like any other film I've used and gives me great contrast.There is a learning curve like anything but YOU have to figure it out for what works for your printing style! No need to bleach off the emulsion or anything else. It is not rocket science. I'm going to print a 14x17 negative that has a density range of 1.78. The neg's is from 2.08 to .30. I've posted images that I have shot on x-ray film and printed in carbon on the forum. Now, I'm sorry to seem upset as I am not but just "DO IT!"

Mark Woods
25-Apr-2011, 18:48
Jim, you missed my irony and theoretical analysis. Good to see we rattled your cage. ;-) Hope all is well in Ventura.

Jim Fitzgerald
25-Apr-2011, 19:34
Sometimes I'm slow on the uptake but I am burning a couple of 14x17 carbon prints from x-ray film! Can someone explain how the green sensitive reacts to the NuArc's 1000 watt light and how this translates to the proper sensitizer for a green sensitive material..... I'm confused!!

Greg Blank
25-Apr-2011, 20:06
My guess, UV. Welders spit a lot of UV which can actually sunburn you if your skin is not covered. X ray would be close to the UV spectrum.

Here is a snipet that seems to confirm,....I not a physist, yet :)
Ultraviolet

The region just below the visible in wavelength is called the near ultraviolet. It is absorbed very strongly by most solid substances, and even absorbed appreciably by air. The shorter wavelengths reach the ionization energy for many molecules, so the far ultraviolet has some of the dangers attendent to other ionizing radiation. The tissue effects of ultraviolet include sunburn, but can have some therapeutic effects as well. The sun is a strong source of ultraviolet radiation, but atmospheric absorption eliminates most of the shorter wavelengths. The eyes are quite susceptible to damage from ultraviolet radiation. Welders must wear protective eye shields because of the uv content of welding arcs can inflame the eyes. Snow-blindness is another example of uv inflamation; the snow reflects uv while most other substances absorb it strongly.

Frequencies: 7.5 x 1014 - 3 x 1016 Hz
Wavelengths: 400 nm - 10 nm
Quantum energies: 3.1 - 124 eV
Electromagnetic spectrum

Index

HyperPhysics*****Electricity and Magnetism R Nave
Go Back





X-Rays

X-ray was the name given to the highly penetrating rays which emanated when high energy electrons struck a metal target. Within a short time of their discovery, they were being used in medical facilities to image broken bones. We now know that they are high frequency electromagnetic rays which are produced when the electrons are suddenly decelerated - these rays are called bremsstrahlung radiation, or "braking radiation". X-rays are also produced when electrons make transitions between lower atomic energy levels in heavy elements. X-rays produced in this way have have definite energies just like other line spectra from atomic electrons. They are called characteristic x-rays since they have energies determined by the atomic energy levels.

In interactions with matter, x-rays are ionizing radiation and produce physiological effects which are not observed with any exposure of non-ionizing radiation, such as the risk of mutations or cancer in tissue.

Astronomical observations in the X-ray region of the spectrum are obtained with the Chandra X-ray Observatory.

X-rays are part of the
Electromagnetic spectrum

Frequencies: 3 x 1016 Hz upward
Wavelengths: 10 nm - > downward
Quantum energies: 124 eV -> upward
Compton scattering of x-rays Moseley plot of x-rays
Bragg spectrometer Bragg's law

http://hyperphysics.phy-astr.gsu.edu/hbase/ems3.html



Sometimes I'm slow on the uptake but I am burning a couple of 14x17 carbon prints from x-ray film! Can someone explain how the green sensitive reacts to the NuArc's 1000 watt light and how this translates to the proper sensitizer for a green sensitive material..... I'm confused!!

Jim Fitzgerald
25-Apr-2011, 20:38
Wow!!!

Tim k
25-Apr-2011, 21:18
Ok, I'm going to just quietly slip back to the sidelines now. Green it is.

Jim Fitzgerald
25-Apr-2011, 21:44
Ok, I'm going to just quietly slip back to the sidelines now. Green it is.

Tim, any advice you need about the green just let me know. It is a great film to use. I will say that you have to be very, very careful loading and unloading 14x17.

Mark Woods
25-Apr-2011, 22:16
Although Greg's post was very informative and interesting, it has nothing to do with the image once it's developed. Once it's developed, the image is just like any other image that we print. It is black and white and shades of gray. And, again, I find his information fascinating and informative, it has nothing to do with the color spectrum that we photograph unless one uses some radioactive source as your light source. Again, I would suggest the theoretical concept that a given color sensitive film is much like using a narrow band color filter to expose your image. A green sensitive emulsion would be like putting on a narrow band (550nm) filter between the subject and the film (i.e., in front of the lens or behind it).

Hope this helps.

John Kasaian
25-Apr-2011, 22:16
Perhap someone can give us curious folks some guidence?
CSX lists four types of green x-ray film:

CSX Ortho Green by Agfa (Agfa?)
Fuji Super HRT Green
Kodak Ortho Green
KodakOrtho Green Latitude

Which green to start with? Which one do you guys use?

Mark Woods
25-Apr-2011, 22:29
I use the CSX Ortho, but it's really sensitive. I rate it at 320 EI. Not familiar with the others.

Vaughn
25-Apr-2011, 22:49
I am using Agfa Cronex 10TL x-ray film marked "Daylight" (14x17). It expired in June 2002 and I have kept it the fridge since around then. It has a blue base. Don't know much else about it. I just have begun to use it in an 7x17 camera. I did a little 8x10 work with it previously.

Photographing my boys in open shade, I got good exposures at 800ASA -- at 400ASA the negs were overly dense (developed at the hospital). Under the redwoods and developed in the darkroom, I rate it more around 200ASA -- based on the shadow detail...then give it an extra stop if the exposure is long. Can't say I have used it enough to get a firm grip on its properties yet.

Just found this:


AGFA Cronex X-Ray Film

Cronex 10TL is a medium-contrast, half-speed, bluesensitive
film for use in general diagnostic and special procedures radiography. It is recommended for use with Agfa blue-emitting screens. Cronex 10TL has a cool blue tint designed to reduce eye fatigue. Its state-of-the-art anti-static properties enhance its performance during film handling, processing and digitization.

From: http://ccxmedical.com/X_ray_films.html

So that explains why it is so much faster in open shadows, yet slower in the forest. Full-speed blue must go like a rocket!

And thanks to Google, I found, from a 2004 article:


...The plaintiff, Eastman Kodak Co., alleged the defendant, Agfa- Gevaert N.V. and Agfa Corp., manufactured and sold radiographic films that infringed on seven of its crossover and tabular grain patents. By limiting the amount of light that crosses over from one side of the film to the other, the crossover patents prevent distortion.

The benefits of the tabular grain (T-grain) patents include the capturing of more light at a lower cost compared to grains in other films and capturing that light more accurately, resulting in clearer images....The court first addressed Kodak's Sept. 7, 1995 letter to DuPont which stated Kodak's belief that DuPont's Cronex 10T product infringed upon two of the T-grain patents...

While the court held the letter constituted proper notice of infringement with respect to the Cronex 10T film, the court did not find the notice extended to other DuPont products that also involved T-grain patents...

This is interesting in that even though the film is double sided, I do get a sharper print when contacting the side that faces the lens against the carbon emulsion. From the above, it would appear that most of the exposure is on the side facing the lens, and the opposite side receives less light due to the patented crossover prevention technologies...IF the Cronext T is similar to the TL, anyway.

Vaughn

Jim Fitzgerald
25-Apr-2011, 22:50
John, funny thing is I shoot my Ortho Green at ISO 80. Works very well for my carbon printing. Great negatives. I think everyone has to find their personal EI.

BetterSense
26-Apr-2011, 05:56
I use the CXS green latitude for silver printing. For being cheaper than paper, it's satisfactory.

Jim Fitzgerald
26-Apr-2011, 08:34
Okay so to answer some questions that everyone has and to show an example here is a print I made last night. Shot on 14x17 Green x-ray film, developed in Pyrocat-HD in a tray 1:1:100 for 6 minutes. I pre-soaked for 3 minutes developed and water stop and then TF-4 fix. This is a carbon transfer print with my own lay down tissue and my own pigment recipe. The image was take with my 14" Darlot shot wide open @ F-4. Now this is only part of the image as my scanner can not get all of the 14x17 image. BTW the DR of the negative is 1.78. The range was from 2.08-.30. I'm okay with this. Works for landscape, still life, portraits, etc.etc.
This is the straight scan of the print and not a negative inverted. So here is an example for all to see. So @ .50 a sheet for 14x17 do you see why I built my 14x17 camera? This is a no brainier and it works for me as I have no brains to begin with!!

Greg Blank
26-Apr-2011, 10:58
I'll admit my thought process was Jim was making exposures on the film using the Carbon Arc instead of prints. My point was that UV and xrays have a cross over at ten nanometers. Inferred by that the film and light sources must correspond to allow carbon arc and xray sources to expose said film perhaps similarly.



Although Greg's post was very informative and interesting, it has nothing to do with the image once it's developed. Once it's developed, the image is just like any other image that we print. It is black and white and shades of gray. And, again, I find his information fascinating and informative, it has nothing to do with the color spectrum that we photograph unless one uses some radioactive source as your light source. Again, I would suggest the theoretical concept that a given color sensitive film is much like using a narrow band color filter to expose your image. A green sensitive emulsion would be like putting on a narrow band (550nm) filter between the subject and the film (i.e., in front of the lens or behind it).

Hope this helps.

Tri Tran
26-Apr-2011, 11:12
Guys, I'm sorry to be so negative with my following comments. Get a box of each and try it out already! It is so f'nig cheap just get some green like I did and shoot it at ISO 80 develop it in Pyrocat-HD in tanks or trays for 6 minutes and you are done. Then dry it and print it in carbon. It works great for me and I'm no wizard. Why did I pick green? Because I like the color!! My understanding is that the screens that they use it the x-ray world give it its sensitivity. Why are we trying to analyze this. It works like any other film I've used and gives me great contrast.There is a learning curve like anything but YOU have to figure it out for what works for your printing style! No need to bleach off the emulsion or anything else. It is not rocket science. I'm going to print a 14x17 negative that has a density range of 1.78. The neg's is from 2.08 to .30. I've posted images that I have shot on x-ray film and printed in carbon on the forum. Now, I'm sorry to seem upset as I am not but just "DO IT!"

Chillax my friend, save your energy :)
I Had a Dream! I think we should start writing a book called Carbon print revealed with Xray film. More details later.

Tim k
26-Apr-2011, 18:54
Tim, any advice you need about the green just let me know. It is a great film to use. I will say that you have to be very, very careful loading and unloading 14x17.

Thanks Jim. Nice print by the way.

Curt
26-Apr-2011, 19:06
I just ordered a box of 11x14 Kodak Ortho Green from cxsonline and it was cheaper than the other brands. I haven't heard about anyone using Kodak film, Fuji, Agfa?, and house are mentioned but not Kodak. If there anything wrong with cheaper and Kodak?

Curt

Jim Fitzgerald
26-Apr-2011, 19:24
Curt, cheaper is just fine. I've tried several different brands and shooting them all at 80 and they work fine. BTW if you are still in need of some 11x14 holders let me know. I have two to sell for a friend.

Jay DeFehr
26-Apr-2011, 21:08
Curt,

I just ordered a box of 8x10 Kodak Green Ortho X-ray film from CSX, so we can compare notes. My main intention is to use the film to test a camera I'm building, so I don't have to use my expensive stuff.

Curt
26-Apr-2011, 23:24
Jim, thanks I'm beginning work on the holders but if it totally doesn't work out I'll pay the piper and buy one or two S&S.

I've got to make the bellows and put the back together but the camera is about done. For anyone who is going to make a camera I have one piece of advice. Don't make one out of parts from an older donor camera. The time spent on the conversion could be better spent by building from scratch.

At 55 cents a sheet, more or less, the cost of 11x14 has gone though the floor! I think when I'm done I'll make a folding 11x14 field camera similar to Tim's.

At that time I'll probably have Camera Bellows make one for me. On this build the cost was between $500 and $600 for one, that's too much for this type of camera build. I just wanted to get going in the larger format. In retrospect I should have just made one from the ground up as I said but I'm not giving up.

I wouldn't mind having a 10x12 either or even a 7x17.

Curt