That depends on the paper. Most RC brands will top out at a minute at the recommended temperature and will develop very little more. Highlight fogging can occur if overdone. FB papers I've developed 2 to 5 minutes depending on the brand. I like giving it more time than the spec sheets say, I find it gives the blacks a bit more depth on many papers.
That depends on the paper. Most RC brands will top out at a minute at the recommended temperature and will develop very little more...
That's not my experience. I can't find a 'top out' point. In my tests development continued after the shadows reached Dmax. With midtones and highlights getting continuously darker. Dr. Henry has a graph in his book showing the effect. Highlight fogging happens after that. I think the term 'developing to completion' needs to be reconsidered.
Originally Posted by glbeas
...FB papers I've developed 2 to 5 minutes depending on the brand. I like giving it more time than the spec sheets say, I find it gives the blacks a bit more depth on many papers.
This is my experience too. Ilford, for example, told me that their spec was written for commercial labs, where speed is of the essence.
I think the term 'developing to completion' needs to be reconsidered.
I don't mean to contradict but wouldn't you say bulk of development process is done in first 30 seconds or less and after that, the rate of development slows down significantly? It looked as if at 60 seconds mark, the process has slowed to a point where it appear to have stopped.
I've tried 60 seconds and 90 seconds, and saw no difference. Then, I left the paper in for 10 minutes and saw a significant difference.
That's not my experience. I can't find a 'top out' point. In my tests development continued after the shadows reached Dmax. With midtones and highlights getting continuously darker. Dr. Henry has a graph in his book showing the effect. Highlight fogging happens after that. I think the term 'developing to completion' needs to be reconsidered.
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Any recollection of which brands? The only RC I've used that didn't top out was the old Oriental paper, man that stuff was good!
Seems like the manufacturers have mediocracy as a goal, so many times something really good shows up it and gets killed after a while for some reason or another and the lesser products seem to just go on forever.
Well, maybe we need to define what is meant with 'top out' or 'develop to completion'. If it means 'reach Dmax', then yes, that does happen fairly quickly. However, if it means 'no further development' for any of the tones in a print, then no, I was never able to find the point in time when development stopped with RC or FB. It seems to continue beyond highlight fogging.
As one can see from the attached graphs, development actually never stops for any print tone that has not reached Dmax yet.
The attached test results are for Ilford MGIV-RC&FB, but I have done the same test with Agfa and Kodak papers with similar results.
So my 3 min. sound about right or not long enough????
3 minutes sounds about right for FB paper. I use Ilford MGIV-FB with factorial development for which I time the first appearance of midtones and multiply this time by a factor of 6 to find the total development time. Using this method, I usually end up with 3 minutes in fresh and up to 4 minutes in nearly exhausted developer. Factorial development is useful to compensate for developer exhaustion as well as for temperature fluctuations.
As one can see from the attached graphs, development actually never stops for any print tone that has not reached Dmax yet.
The attached test results are for Ilford MGIV-RC&FB, but I have done the same test with Agfa and Kodak papers with similar results.
Very interesting Ralph, thanks for posting this, I didn't know this, or at least hadn't seen it so well shown.
However, two questions:
- To what extend might safelight fogging influence the results you graph out? Are these graphs from papers developed in absolute darkness? Considering no safelight is actually truly "safe", I would expect at least part of this issue related to slow safelight fogging with the extended times in the developer.
- Am I right the "0.00" value / line is for the "blacks", while subsequent higher numbers are the negative densities of the "highlights" in your graphs (just to make sure I do really interpret them right)?
"The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true." - William M. Ivins Jr.
"I don't know, maybe we should disinvent color, and we could just shoot Black & White." - David Burnett in 1978
"Analog is chemistry + physics, digital is physics + math, which ones did you like most?"
Very interesting Ralph, thanks for posting this, I didn't know this, or at least hadn't seen it so well shown.
However, two questions:
- To what extend might safelight fogging influence the results you graph out? Are these graphs from papers developed in absolute darkness? Considering no safelight is actually truly "safe", I would expect at least part of this issue related to slow safelight fogging with the extended times in the developer.
- Am I right the "0.00" value / line is for the "blacks", while subsequent higher numbers are the negative densities of the "highlights" in your graphs (just to make sure I do really interpret them right)?
Marco
Marco
Your interpretation of the values is correct. My (red) safelights are tested to be 'safe' for up to 32 minutes. These tests show developing times up to 6 minutes. Consequently, safelight fogging can be ignored.
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Originally Posted by glbeas 
