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

[Corran]

I suggest Rodinal 1:100 like you say. It's worked just fine for me with Fuji HR-T, and that has the double-sided emulsion.

You don't have to know the true speed of anything, you just need to evaluate your negs. If you are having shadow values that are too low, give it more exposure, and if you want to pull your highlights, give it less development.

[Peter De Smidt]

You determine film speed. Shoot a evenly lit black card in shade. Use your best educated guess as to what the EI of the film is. Set that on your meter. Now meter the card and place the resulting value on Zone I, i.e. close down 4 stops from the meter reading. Take the photo. Close down one more stop and take another photo. Open up two stops and take a photo. You now have exposures bracketing your estimated film speed by 1 top over and under. You can do more if you're really unsure, but for 8x10 I'd just do the three. Develop the film using your best guess. Read the negatives with a densitometer. You want Zone 1 to read _at least_ .1 above film base plus fog. I prefer the value to be about .15. Does that correspond to one of your sheets? If it falls between the ranges your sheets give you, estimate the EI value that'll give you what you want. If there's not enough density, do the test again, starting with 2 stops more exposure than the first test. If it's more, do the same but giving 2 stops less for the starting exposure.

Once you have your film speed, do a development test. Photograph an evenly lit blank white card in sunlight. Set the EI you determined on your meter. Meter the card, making sure it's evenly lit. Read your meter and open your lens to 3 stops more than the meter reading, which places that value on Zone VIII. Take two more exposure exactly the same. Develop one of your negatives. For diffusion printing, the value should be about 1.3 above film base plus fog. If you're not there, estimate the change in development. Develop the next sheet, measure, estimate, and develop the last sheet if needed. If you're development is way off, you might have to do it again.

You now have your N development. You can test it by exposing one neg for the black card placing it on Zone I.....

This sounds complicated, but it really isn't. It also doesn't take much time to do.

[StoneNYC]

Thanks Peter and Corran, Peter, that sounds like the most perfectionist way to do things, however I don't know that it's exactly quick to do, that would take me at least a whole day to do, and I don't own a densometer (nor can I figure out how to spell it right so that spell check agrees). I go by the general look of the density of the negative, this has served me well all along. My "testing" is usually done by shooting, and not by performing a lot of tests, even "bad" exposures are usable they just take a little more effort to print, so I find doing lab tests to be time consuming, don't hurt me, I know they are the most accurate way to do things, but I also need to make sure not to deviate too far from my current working habits or that throws everything off as I'm changing too many variables at once. If I can't find an acceptable negative in my next attempt then I'll try out Peter's system, I know it totally makes sense, but again, this would take me a whole day, I work out of my kitchen so the setup and cleanup and developing and processing, I don't have a lot of days to set aside to developing work that I'll never use. YMMV (obviously), but I value the suggestions.

[Peter De Smidt]

It's not my system. The whole point is to eliminate variables and simplify getting to good exposure and development. Having that well in hand would save you a lot of time, money, frustration and lost opportunities in the long run. There have to be a number of people near you that have densitometers. Any pro film lab will have one. In addition there have to be a bunch of people here who would help you, including some that live in your area, but if that's not available, send the film to me, and I'll take readings for you.

[StoneNYC]

It's not my system. The whole point is to eliminate variables and simplify getting to good exposure and development. Having that well in hand would save you a lot of time, money, frustration and lost opportunities in the long run. There have to be a number of people near you that have densitometers. Any pro film lab will have one. In addition there have to be a bunch of people here who would help you, including some that live in your area, but if that's not available, send the film to me, and I'll take readings for you.

Yes, there are a few in boston if I want to drive about 3 hours (one way) and some in NYC if I want to fight traffic for 2-3 hours (one way) and then if they don't want money for the borrowing.

There's a few LF'er's in the state (somewhere) but they all meet in Massachusetts, and I haven't joined that LF New England group yet. There's no one within a 1 hour drive that I know of, so again, it's a little far to go, we'll see where I get with the next batch.

[Andrew O'Neill]

Thank you! Are you referring to my carbon transfer video?

[premortho]

Personally, I've only done one of those film tests in my life. About 50 years ago, when ortho film became hard to get (it's easier now than it has been for 50 years!). With ortho film I did then and still develop under a red safelight in trays. It takes a few shots to learn when to pull it out of the developer, but you get a feel for that soon enough. I am so used to doing that, Stone, that I forgot to mention it earlier. As to filters, a 2X is about a medium yellow. The yellow filter holds back the uv, violet and sky blue part of the spectrum. For me it gives (allows) more exposure of the shadows without blowing out the highlights as easily.

Yes, there are a few in boston if I want to drive about 3 hours (one way) and some in NYC if I want to fight traffic for 2-3 hours (one way) and then if they don't want money for the borrowing.

There's a few LF'er's in the state (somewhere) but they all meet in Massachusetts, and I haven't joined that LF New England group yet. There's no one within a 1 hour drive that I know of, so again, it's a little far to go, we'll see where I get with the next batch.

[StoneNYC]

Thanks!

Yes I've actually done ortho developing in trays before and can pull the film when needed, just like print paper, I'm working on a small project now with that.

Thanks.

Personally, I've only done one of those film tests in my life. About 50 years ago, when ortho film became hard to get (it's easier now than it has been for 50 years!). With ortho film I did then and still develop under a red safelight in trays. It takes a few shots to learn when to pull it out of the developer, but you get a feel for that soon enough. I am so used to doing that, Stone, that I forgot to mention it earlier. As to filters, a 2X is about a medium yellow. The yellow filter holds back the uv, violet and sky blue part of the spectrum. For me it gives (allows) more exposure of the shadows without blowing out the highlights as easily.

[andrewch59]

Andrew, yes, you make it look easy, I haven't tried it yet, but it is on my bucket list

[stiganas]

For anyone who might be interested.

The 18x24 xray film goes perfect, without trimming in the 18x24 holders.

Nice Carbon Transfer Video, I start dreaming (and searching for chemicals) about it.

I am from Romania, here (as I suppose all over Europe) the easily available sizes are only metric:
13x18, 18x24cm and so on.

My question is:

it will go in 18x24 holder without trimming ?