matching film and paper curves

[AlanC]

Writing in the latest edition of Black and White Photography magazine Mike Johnston mentions that the highlight contrast of Ilford paper is formulated to match Ilford film, and therefore doesn't suit Tri X, which has different highlight contrast.
I am no expert when it comes to characteristic curves of film and paper, and would like to know more about this. Can anyone help?

Alan Clark

 

[Photo Engineer]

If you are exposing on the straight line of the film, which is normal with a normal exposure, then both kinds of films will work the same way. If the film has a pronounced shoulder, then if you overexpose you will be on the shoulder and that is what you see on the paper in the highlights.

OTOH, all papers have toes where the highlights are reproduced from the shoulders of the films. The toe of Ilford papers is rather similar to that of Kodak papers and others that I have seen.

So, I think that this is a myth. I would consider it so until he shows data to support his POV rather than just a 'mention'. You might be able to prove it yourself by getting a characteristic curve of each film from the mfgrs. web site and comparing them in the middle where a good exposure should be.

PE

 

[gainer]

You are right, PE. Even if Ilford films and papers were designed for each other, a little change in exposure and development might very well bolix up the agreement. We can talk about straight line portions, but we seldom see one. If we did run across such a thing, the tones in the print would of necessity be distorted in some way in the attempt to get a black black and a white white because every paper I have seen is not linear on bothe ends of the curve. The curves for different films with different developers published some years ago in "Darkroom and Creative Camera Techniques" (now "Photo Techniques") showed so many different curve shapes for the same film that one might wonder how a decent print could be made with all the curves on one type of paper or of one film curve on different paper curve shapes. There is a chapter in "Theory of the Photographic Process" that deals with the subject of tone reproduction. With proper exposure and development, film and paper curves that are as crooked as a dog's hind leg can be made to give beautiful prints.

We are not usually looking for absolute accuracy of tone reproduction anyway. We may prefer some particular kind of tone distortion because it emphasizes some aspect of our favorite type of subject. Some like to overexpose, which may make true tone reproduction impossible with any but truly linear film and paper curves, but suits some creative purpose.

I don't mean to be dogmatic about the subjective, just to add some freight to the train of thought.

 

[gainer]

Subjective? I really am getting old.

 

[Daniel_OB]

"Even if Ilford films and papers were designed for each other..."

Are you jocking? It must be some fun.
Curve and for paper and for film depend of developing time. To match film and paper one should make density-exposure curve and for film and for paper, place them both into Decart-coordinate system and make some graphical trickery (cannot make with words).
Fully developed paper nerly is undepend from developing time (developer plays role here), just for different papers D-max is different, but for film D-Exposure can be changed to match the paper.

And what is meaning of "to mach the paper" is a story for itself. It is depends of photographer and working style. Some want full details some not.

And not all ilford films has the same curve slope at the same exposure (say zone III).

There is no such think as one film match one paper. It is just adjustable, and NO maker mater, but well one need to know how to do it.

PE: I am sure you know that are so rare films (and developer) that shows a straight line on Density-Exposure.

Alan: you have two choices, or just use it (films and paper) no mater manufacturer as you mentioned, or deep into experimentation, which will not help a lot at this moment for it requires really a long time of learning. Curves published no matter where are totally unuseful so do not look at them. whereever they are published they are made by working standard od a guy made them. There are so many influental factors on that Density-Exposure curves that you have ZERO chance to get the same curves by your own working standard. One example: I recently moved 30 km (20 miles) and had to retest all my films. So there will be no answer on your question which you will be able to apply NOW. Answer on your question is: if you try to control phot process then warm up the chair for a couple of years. Good luck.

www.Leica-R.com

 

[AlanC]

Photo Engineer and Gainer,
Many thanks for your very interesting replies to my query. After reading them I feel quite safe to carry on using Tri X and printing it on Ilford Warmtone paper!
Gainer, your point about us not always looking for accuracy of tone reproduction is an important one. I recently used a 5 x 4 FP4 negative to make a print on Ilford Galerie. It's contrast matched grade 3 very nicely, and the resulting print looked ok. I then made another print from the same negative on Ilford Warmtone fibre paper. This looked far better. The print had a real glow to it. It was the midtones. On the galerie print they were slightly darker than they should have been, and on the warmtone paper they were slightly lighter. The result was about a two zone difference, and this really brought the warmtone print to life, despite being tonally "wrong"

Alan Clark

 

[Photo Engineer]

Well, now you know how myths start!

This guy throws something out there and people read it and believe it.

Of course, Ilford tests their paper with their film, I have no doubt about that, but Ilford and Kodak film are not that far apart in contrast and tone scale. There are laws of physics and chemistry that come into play here that limit the possible directions one can go.

Yes, your comments about the different papers make sense and I have seen the same thing. That is why I say "use what works for you" as everyone uses a different exposure, developer, film, paper combination that yields a unique result.

Having designed both papers and films, I can say that this guy has just tried to give some depth to his writing with no evidence to back it up whatsoever.

PE

 

[AlanC]

Photo Engineer,
Once again, what you say makes a lot of sense. I knew I should have backed my own judgement!
Thanks again,

Alan Clark

 

[Rick Jones]

Alan - this is not the first time Mr. Johnston has written an article on this subject. Years ago I contacted him asking just how one goes about picking a good fit between paper and film. He was kind enough to reply but never answered my question. There certainly seems to be some disagreement about the value of this matching question. In the March/April 2007 issue of Photo Techniques Fred Newman wrote an article titled "Image Gradation:Matching Your Papers to Your Films" in which he explains how a computer program designed by Phil Davis can help choose film paper combinations which can "make our job as photographers easier". If you would like to learn more about the issue from Fred's prospective read the article and/or contact him at the View Camera Store as the article suggests ( fred@viewcamerastore.com).

 

[AlanC]

Rick,
Thank you. I may contact him. However, since posting the original question I've made a few work prints on Ilford Mg 4 using 35mm Tri X and HP5 negatives of similar subjects, taken at the same time. If Mike Johnston is right I should have had better highlight rendition with the HP5 negatives. ( He said in the article that Ilford had re formulateed their paper to match the highlight contrast of HP5)
But guess what? The only problems I encountered were getting the highlights to print properly with some of the HP5 negatives! The Tri X negatives printed easier.
I have had this problem in the past with HP5 and subsequently abandoned it and have been trying other 400 speed films. I had just finally settled on Tri X when I read Mike Johnston's article, and started to have doubts.
All this has taught me that the best approach is to do my own tests and back my own judgement.

Alan Clark