What happened? (Processing 8x10 x-ray film)

[James Drukeli]

I have an 8x10 camera which I've shot a few negatives and it has been a complete failure. I think I'm doing everything right but must have missed something. I've processed 2 negatives at different times with no success. The first negative I got the faintest partial image when held up to light but pretty much unrecognizable. The film was very black and the emulsion was easily rubbed off with my finger nail. My second attempt yielded a completely black negative with no image whatsoever.

Here is my process, worked under a 6watt red safelight.

1. Exposed the negative. Each time was a different shutter speed and aperture.
2. developed in D76 1:1 for 9 minutes at 20c.
3. Stop bath tap water for 2 minutes.
4. fixed with ilford rapid fixer for 5 minutes.
5. water wash and hang dry.


Any ideas what's going wrong?

The x-ray film is fuji super HR-T 8x10 green latitude.

The sheets appear to have an almost silver tone tone to them. Once I put them in the developer they turn dark black after about 5 minutes but no image ever resolves. When I'm finished i'm left with a black negative, no image, and the emulsion is almost gooey and easy removed with a light fingernail scrape.

 

[Daire Quinlan]

Massively overexposed ? What speed are you shooting them at ? When you say they 'turn black after about 5 minutes' are you developing under a safelight ? The emulsions on the x-ray films I've used have been pretty soft after dev & fix, I'd be careful around them until they'd dried out completely.

 

[Rick A]

You would probably do better asking on this site:
https://www.largeformatphotography....film-technical-discussion-with-example-images

 

[Andrew O'Neill]

The emulsion is a gooey? Could be something wrong with the film itself.
What ISO did you use? D76 1+1 dilution is most likely too strong. Try 1+3 or weaker.

 

[James Drukeli]

Massively overexposed ? What speed are you shooting them at ? When you say they 'turn black after about 5 minutes' are you developing under a safelight ? The emulsions on the x-ray films I've used have been pretty soft after dev & fix, I'd be careful around them until they'd dried out completely.

The first exposure was 1 sec and the second was 1/5. The second shot turned out completely black.

Yes developing under 6watt red safelight.

 

[Andrew O'Neill]

The first exposure was 1 sec and the second was 1/5. The second shot turned out completely black.

Yes developing under 6watt red safelight.

No... what ISO?

 

[James Drukeli]

No... what ISO?

estimated at IS0 100

 

[Andrew O'Neill]

estimated at IS0 100

HA HA we're both bouncing between both forums!

 

[James Drukeli]

So i figured it out. It was my safelight. I guess the red bulb wasn't the right type .

 

[Luckless]

A member here, Greg Davis, has some YouTube videos on safelights and safelight testing that might be worth looking up.

There are a number of "Red" lights currently on the market that put out a pretty broad spectrum of light that can be hard to notice if you're not paying attention.

Also a good time to remember that not all films/papers need the same safe light.
[And if you rig your work space with different safe lights for different uses, remember to have your coffee before turning them on to start work. They're not very safe if you have the wrong one on.]

 

[MattKing]

An X-ray product is not likely to be designed for the same safelight as darkroom printing paper or even lithographer's film.

 

[juan]

On the large format site there are links to led safelight bulbs from superbrightbulbs that work well with X-ray film. I have one and use it regularly.

 

[DWThomas]

I use Fuji HR-T and found those small red LED bulbs did not work without a Rubylith filter added. LEDs typically have a very non-continuous spectrum and a very narrow output toward blue or green can be a problem even though our eyes don't see it. There are those who suggest looking at the light reflected off a recorded CD which can display the spectrum. Mayhaps my eyes are too old, but I didn't find the results of that confidence inspiring, so I just experimented with the red filtering of Rubylith. The experiments were because a Kodak #2 dark red in one of those classic "bullet" safelights works, but seemed barely better than groping in the dark.

 

[Daire Quinlan]

So i figured it out. It was my safelight. I guess the red bulb wasn't the right type .

Ah, yes that's why I was asking :-D Good to find out anyhow. @DWThomas only way to be sure is to test it out, classic coin on a sacrificial sheet of film exposed to the safe light and then developed.

 

[Luckless]

Ah, yes that's why I was asking :-D Good to find out anyhow. @DWThomas only way to be sure is to test it out, classic coin on a sacrificial sheet of film exposed to the safe light and then developed.

the specific video I had mentioned earlier.

The basic coin test as often suggested is potentially rather dangerous to trust, as may give a false sense of security in lights that are actually unreliable.
An improvement on the test of "Leave your paper/film out in the safe light with a coin on it for awhile, then develop and see if the exposed areas darkened" is to include some manner of pre and post flashing.

Physics are weird, but below a specific overall energy level you don't start to see a noticeable change in the light sensitive material. Give it a bump of higher energy, such as part of a proper exposure, and suddenly the tiny low levels of light that showed no impact on an initial coin test can begin to accumulate and darken the film/paper.

And this seems like an important bit of information that is far too often forgotten or overlooked in the film community.

 

[DWThomas]

@Luckless makes a good point, and I did in fact, do some work in that direction, but for a first pass a nickel on a piece of film indicated 'trouble ahead!' There is or was a Kodak publication that described a safelight test method that is quite a rigamarole but no doubt appropriate for serious work

I'll add for the OP:
I meter at ISO 50 for HR-T, but I'm using it for pinhole with rather long exposures (and likely reciprocity issues), so metering is not quite as precise as one might like to imagine. I have settled on developing it in HC110 1+63 for about 3:30 @ 68ºF to rein in a tendency to higher contrast. A few years back when I started with HR-T I searched a number of photo forums and claimed numbers were all over the place. And of course, Fuji doesn't spec it for normal photography so one really needs to experiment in a vaguely systematic way and keep good notes until arriving at a usable work flow.

I also tray develop the 8x10 sheets one at a time in Cesco trays with a smooth, flat, matte finish bottom to avoid scraping the emulsion which is on both sides. (But I generally only shoot between 2 and 10 sheets on Worldwide Pinhole Photography Day once a year.)

 

[MattKing]

There is or was a Kodak publication that described a safelight test method

https://www.kodak.com/uploadedfiles..._motion_products_filter_K4_Safelight_1106.pdf

 

[DWThomas]

https://www.kodak.com/uploadedfiles..._motion_products_filter_K4_Safelight_1106.pdf

Thanks Matt!

 

[AgX]

An X-ray product is not likely to be designed for the same safelight as darkroom printing paper or even lithographer's film.

Yes, X-ray film is not X-ray film. There are various sorts.
A great share of the medical ones are spectrally sensitized as they are are mainly exposed by the intensifyer sheet.

Aside of that all X-ray films are intended for automated processing, even rapid access.
Thus I am surprised of learning of soft emulsion.

 

[Daire Quinlan]

Aside of that all X-ray films are intended for automated processing, even rapid access.
Thus I am surprised of learning of soft emulsion.

IIRC the problem is that conventional dev (in dentists & hospitals etc) would use a hardening fix, which is uncommon nowadays. Most people would probably have rapid fix readily available which leaves the emulsion somewhat soft.

 

[KN4SMF]

You need to use acid hardening fixer. This film is very soft and slimy.

 

[AgX]

Thank you both!

 

[Andrew O'Neill]

I have never used an acid hardening fix with many brands of Xray film. Double-side, single-sided. The emulsion is delicate, but certainly not slimy.

 

[koraks]

I have never used an acid hardening fix with many brands of Xray film. Double-side, single-sided. The emulsion is delicate, but certainly not slimy.

Dito. Moreover, a hardening fixer doesn't change anything about the emulsion during the processing stage when it actually matters. When dry, the emulsion on these films is perfectly easy to handle without damage.
The problem during processing is the much thinner (it seems) and softer topcoat. No hardening fixer is going to change a fundamental property of the emulsion design.

 

[KN4SMF]

Dito. Moreover, a hardening fixer doesn't change anything about the emulsion during the processing stage when it actually matters. When dry, the emulsion on these films is perfectly easy to handle without damage.
The problem during processing is the much thinner (it seems) and softer topcoat. No hardening fixer is going to change a fundamental property of the emulsion design.

Well obviously the emulsion is soft in the developer. That what developer is, and does. And I've found X Ray film is especially slimy-soft in the developer. Easy to damage. And transferring it to stop bath leaves all sorts of ways to scuff it. But once it hits that nice fresh Kodak Fixer (or similar), the gelatin hardens up quite nicely compared to previously. Just because you're out of the developer doesn't mean you're home free. When you're dealing with x-ray film, scratches materialize out of thin air. NOT having scratches is nothing less than a miracle.