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Human friendly fixer

wiggywag said:
When you use such fast fixers that require only 1 minute fixing, when is it safe to turn the lights on? After 30 sec?
Click to expand...

I'm not as brave or rushed as BetterSense, consequently, I play it save and wait until fixing is completed.
 
Ralph,

Your BF-1 formula appears to call for solid-form Ammonium thiosulfate. I thought this was usually sold in liquid solution. What's the conversion factor?

Thank you.

steve
 
I believe my choice now stands between Ilford Hypam Fixer, which should be fast and odorless, and Kodak Kodafix. Are they very similar?
 
If you are using an acid fix, turning the lights on after 1/2 the suggested total fix time is reasonable, but if you are using a neutral or alkaline fix, you should wait for the full time to elapse. This suggestion is especially true if you are not using a stop bath.

PE
 
Steve Goldstein said:
Ralph,

Your BF-1 formula appears to call for solid-form Ammonium thiosulfate. I thought this was usually sold in liquid solution. What's the conversion factor?

Thank you.

steve
Click to expand...

That depends on the percentage of thiosulfate in your liquid solution.
 
If you are using an acid fix, turning the lights on after 1/2 the suggested total fix time is reasonable, but if you are using a neutral or alkaline fix, you should wait for the full time to elapse.
Click to expand...

What are the effects of not waiting that long? I have tested and found no visible change in the prints. It was my understanding that fixer will fix exposed-but-not-developed paper and film just fine...otherwise everything would have to be developed to completion after all.
 

The carryover of developer into an alkaline fix creates a monobath condition in the paper. The amount of carryover is dependant on whether it is FB or RC. It also depends on how good the rinse is or whether you use a stop bath.

Given the presence of developer, alkali and light, the paper becomes fogged and the monobath does its job which varies according to the paper, as above, time and the state of seasoning.

I have tested this extensively while formulating new fixes and find that the result can be gray whites or an actual yellowing of the paper.

PE
 
Only with an alkaline fix, though? I only use RC paper, acid fixer and common rapid fixer.
 
RalphLambrecht said:
I'm not as brave or rushed as BetterSense, consequently, I play it save and wait until fixing is completed.
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OK. Caution is a good thing. But in reality, if you've used an acid stop, once the print is in the fixer (assuming the fixer is fresh and not exhausted) no more development will take place. I have tested this by making two identical prints. One was subjected to lights on as soon as it was completely immersed in the fixer. The other was subjected to lights on only after complete fixing - two minutes for an RC print in rapid fixer. Result? No difference whatsoever that I could see by eye.
 

The problem is that sometimes the yellowing or discoloration may take a while if it happens at all. Very fine colloidal silver can form in the coating and this can "bronze" with keeping.

It is best to fix for at least 1/2 the suggested fix time with a fixer before turning on the lights.

PE
 

I will never understand the rush. Why not wait another minute and be save?
 
Ralph, I agree. The only time I hasten to turn on the lights is to examine a test print and see what I have to do next in terms of exposure and dodging. Ah well, let them do what they want, right?

PE
 
I will never understand the rush. Why not wait another minute and be safe?
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Someone else could think 2 minutes was the minimum and wonder why you didn't wait yet another minute "just to be safe". Why not wait another 35 minutes and be 35 times as safe? Probably because and testing shows that 1 minute is "good enough". And there IS such a thing as "good enough". You have to base your decisions on something, and you have to be careful to dispel superstition. If waiting that extra minute in the dark is not necessary then there is no "to be safe" about it, and you are just being silly. You could justify any number of random things on the basis of "just to be safe".

In this case it's probably a good idea to fix the paper in the dark, but if I'm using RC paper I don't notice any difference if I turn the lights on after the paper is thoroughly stopped in acid stop bath and put into rapid fixer.
 

You are grossly exaggerating now. I said, why not wait another minute (to the end of the fixing sequence) and be safe. That's a far cry from standing around for 35 minutes for no reason whatsoever. I think PE gave a good explanation why not to pull the print too early from the fixer. The first time to pull it is probably somewhere between 50-100% of the total fixing time, in which case, we are arguing about seconds. I just don't think that's worth any risk.
 
Yours a Dark Darkroom?

When to turn the lights on? More of a concern
for those using VC paper rather than Graded.
Safelights used with Graded paper pass the
green portion of the spectrum as well as
the red. The eye is most sensitive to
the green portion of the spectrum
and least to the red.

VC safelights trend towards red while Graded
paper safelights trend towards yellow, red plus
green. Quit a high level of darkroom lighting
may be used with Graded papers. Dan
 
I often use a flashlight with a red filter to view prints in the fixer tray to try judging them if I really have to. The only time that is of any use is when I am very much off in exposure or contrast grade. Otherwise, the dim light fools me.

I also use yellow safelights with VC papers, as the green sensitivity of these papers is very very short.

PE
 
On the subject of rapid fixer smells, the very alkaline ones smell of ammonia, acid ones of sulphur dioxide, but there is a spot in the middle at which smell is minimal, somewhere around pH=7.
 
These are the so-called neutral fixes, and the best pH is just slightly acidic for technical reasons. This was first put into large scale practice by Kodak with a series of fixes including the C-41 fix, and the E6 fix. See an example here where someone posted my Super Fix.

PE
 
Odorless Fixers

john_s said:
On the subject of rapid fixer smells, the very alkaline
ones smell of ammonia, acid ones of sulphur dioxide,
but there is a spot in the middle at which smell is
minimal, somewhere around pH=7.
Click to expand...

I found a totally un-doctored ammonium thiosulfate fixer
which measured a ph of 7.8 to be odorless. Decidedly
alkaline sodium thiosulfate fixers are odorless. Dan
 
dancqu said:
I found a totally un-doctored ammonium thiosulfate fixer
which measured a ph of 7.8 to be odorless. Decidedly
alkaline sodium thiosulfate fixers are odorless. Dan
Click to expand...

I think the issue is that to take a rather neutral chemical like Sodium or Ammonium Thiosulfate and make them acid, you mix an acid with it, and the most common one for many years was Acetic Acid, so it had the same strong vinegar smell as stop bath.

A couple of discoveries have been made though, first is that other chemicals like citric acid work just as well for stop bath, and that fixers didn't need to be as acidic as they were. Less acid, even if it's still acetic acid, means less smell.

This however does create another issue, the strong smelling stop baths and fixers of even 30 years ago, had only one defence, good negative ventilation. Less odorous chemicals may mean that darkroom workers are less likely to install good venting. Another solution is to use drums and motor base tanks, as the amount of chemical exposed to the room air will be considerably less.
 
In the details of Formulary TF-5 Archival Rapid Fixer it says:
- Little or no odor if mixed with distilled or filtered water

Does this relates to other fixers as well?
 
RalphLambrecht said:
Acid fixers smell, alkaline fixers don't. Switch to an alkaline odorless fixer if the smell bothers you. But remember, once you go alkaline (acid free), you need to drop the stop bath too and replace it with a water bath.
Click to expand...

is leaving it in a tray of water with agitation enough, or do I have rinse it under the hoose?

How often do i need to change the water if using a tray?
 
I've been using it as my paper fixer, almos no smell, if any at all, in the tray. I also use a low odor stop in trays, makes extended stays in the DR bearable. Even without ventilation the old style, strong smelling chems were not overly offensive. However, in my advanced age, I have become conscious of the need for safer practices and do all I can to limit myself to exposure to chems.
I use TF-4 fix for all my film, even mixed with distilled it has a smell of amonia, but not too awfully strong as to be offensive.
 
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