Just to clarify from a personal point of view I've only carried out a visual comparison with Peter Hogan's alkaline and Fotospeed's acid fixers with 4x5 T-max 100 developed in PMK pyro and I could not see a visual difference as to the amount of stain. They looked the same to me.
Originally Posted by pentaxuser
While I have used Peter's excellent Prescysol developer I have never done a comparison with this developer. Peter clearly states on his website that his alkaline fixer preserves the staining effect.
The effect may indeed be apparent with different films/developers it would be nice if someone could carry out a comprehensive test with various films/staining developers.
Sounds like the basis for an excellent article fro B&W Trevor!
Thanks for your support David but I've just not got the time at the moment. Perhaps Leon will if he's got the time. If he dosn't respond to this thread I'll drop him an email.
Originally Posted by Dave Miller
I agree with Trevor regarding film.
I was using Barry Thornton's Alkaline fix with his developers, then with PMK. The arrival of my Jobo coincided with me running out of the fixer. I did try Ole's alkaline fix listed here on APUG, but the clearing time was ages, so I swapped to Ilford Hypam and have seen no visual reduction in staining. Incidentally I use 1:4, then dilute this 1:1 with water. Makes it more economical as one shot with the Jobo. The choice of Hypam was simple - I had some in the garage!
Thus to the photographer on the street, the staining developers work well with more commonly available fixers.
No wish to hyjack the thread, but does the steel wool method of removing the silver from spent fixer work with alkaline fixers, such as TF-4?
How about silver loading tests, such as Edwal Hypo check?
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IMO (my opinion is based on my own laboratory experience) to evaluate image stain you need a transmission densitometer with the proper spectral sensitivity. Visual evaluation can produce very misleading results.
Originally Posted by Trevor Crone
Last edited by Tom Hoskinson; 01-05-2008 at 07:19 AM. Click to view previous post history.
Everything is analog - even digital :D
Tom, I certainly agree visual evaluation can be misleading, but what was important to me, I saw no clear advantage in printing my pyro developed TMax negs. fixed in an alkaline fixer with negs. fixed in an acid fixer.
Originally Posted by Tom Hoskinson
Obviously to perform a fair test one whould have to produce two sets of negatives exposed at the same time, lighting and subject matter, then developed in the same developer for the same time, agitation and temperature. Then of course split between the two types of fixer. Other films and staining developers would need the same fair tests. This would be quite a time consuming adventure, something I haven't got time to do at the moment. But it would be interesting to see if there are 'real' differences with regard how a finished print would look.
Not a problem Bob. I've been using Kodak's Flexicolor fixer for C-41 for a couple of years now. Works great and it's fast, as you know. PH is close to neutral, about 6.5 at working strength.
Originally Posted by BobNewYork
Dave. If you await my experiment you may be playing the harp or stoking before you get the results! I certainly second the idea of some stalwart such as Leon giving it a go. It's the prints that are the clincher either way.It's precisely that sort of article that would make me buy B&W mag. I do now most months anyway but I give a committment here and now to buy B&W mag when this article is there.
Just one further thought. It may be that Peter Hogan did the experiment himself and has the evidence and could cobble together an article for B&W.
Everything I hear about him suggests that he recommends his alkaline fixer for sound reasons but it would be nice to see an article on it.
Steel wool will work to remove silver from all fixes, and the standard tests for silver retention and exhaustion will work as well.
As for running tests, you see how hard, expensive and time consuming testing films and fixers are. Literally millions were spent at Kodak to come up with these formulations with all the tests mentioned above and more. You see, everything mentioned here plust image stability and image structure were tested with exact quantitative measurments to determine the results. Somtimes it took years to get approval for a new fixer with the results being peer reviewed in-house before release. And, it was done by two groups to avoid bias. The originating engineer had to run these experiments, and then they had to be duplicated by an impartial engineer in another group. Then the results were compared in a peer review.
That is why I accept prepackaged chemistry. It takes the burden off my shoulders. If I do make a new mix, I test it before I use it.
But, an interesting observation has grabbed my attention. All of the 'staining' processes are doing is creat a pseudo dye in the coating around the silver grain. This dye blurs the grain, but can also detract from sharpness. But, my point is this, or rather my question is this. What is the stability of this pseudo dye? What will happen to 'stained' negatives over time. Does the pyro induced coloration fade? It certainly fades or is bleached in acid sulfite fixes. Is it not fair to assume that the stain/tint/dye is less stable than the silver and will change over time?
I just wonder if anyone has run that type of test. Because, if the dye is not stable, then all of this discussion about staining developers is moot.