Yes, we have a computer program at Kodak to calculate Enthalpy of mixing for making emulsions. Temperatures must be very precise at all times.
PE
PE
Air bubbles at edge of frames causing uneven development
-
A
- Thread starter GLS
- Start date
Recent Classifieds
-
Want to Buy Shen Hao TFC617 A or B
- Started by djdister
-
Free CP40Y Color Printing Filtet
- Started by Roger Thoms
-
For Sale For Sale: 55mm ƒ/1.8 SMC Pentax Takumar Lens (M42 thread) and 50mm ƒ/2 Pentax-M
- Started by Kodachromeguy
-
Want to Buy Half Case For Nikon F
- Started by chuckroast
Forum statistics
GLS, thanks for the explanation and link. I had vaguely heard of such reactions between liquids but had no idea that what seems a small portion of IPA to the amount of water would affect that temperature that much. I suppose that one other answer if you want to avoid working out the total effect on average temp over say a 12 minute dev time would be to then cool the mixture until stable before using it
I'll have to try a measure of whisky with my usual small amount of water so in effect the opposite of what you did and stick a thermometer into it and see what happens
pentaxuser
I'll have to try a measure of whisky with my usual small amount of water so in effect the opposite of what you did and stick a thermometer into it and see what happens
pentaxuser
True, but I was impatient to see the results of the experiment re: air bells.
In future it will also be preferable to hit the desired temperature straight away, rather than have to wait
I have had some problems with spots of inadequate development with roll film. I use Pyrocat-HD. Pre rinse has largely eliminated them. Our water is fairly low in dissolved materials. To be on the safe side, I'm considering a drop of wetting agent in the developer (or maybe the pre rinse). These are available locally. Has anybody got particular recommendations for this purpose (in particular avoiding foaming)?
Ilford Ilfotol
FOTOSPEED FS RA50 rinse aid
AGFA MA APH59 Agepon (Compard)
KODAK K Photoflo 200
Ilford Ilfotol
FOTOSPEED FS RA50 rinse aid
AGFA MA APH59 Agepon (Compard)
KODAK K Photoflo 200
Last edited:
PE recommends never ever ever ever ever ever putting wetting agent in the developer. Just ask him.
MattKing
Moderator
I believe that recommendation was with respect to C41 film.
I think I had read this before. When I asked this question I was thinking of Ian Grant's post earlier in this thread. Maybe it's more of a problem with staining developers, or maybe pyrocat in particular. I first got this problem with PMC, a very early version of Pyrocat. Prior to that, I didn't get an air bell or anthing resembling one for 40 years. (But it did coincide with my first use of 120 rollfilm, so two variables).
Alright, here it is for B&W. NEVER EVER EVER put a wetting agent into a developer of ANY sort for ANY film!
PE
ok,ok I believe you! Or how about wetting agent in pre wash?
I could try isopropylalcohol in a pre wash. Is the 5% mentioned in a previous post a good quantity to use?
MattKing
Moderator
Thanks for making things clear PE. REALLY, REALLY, REALLY clear.
Andrew O'Neill
Moderator
I always, always, always put a few drops in Pyrocat-HD part A when doing two-bath development. 
Should be. Although you should also give it a try it in the developer solution. I didn't see any ill effects from it, but it was only the first film I tried so far; more experiments are needed to confirm.
Just be sure you use IPA of a high purity (99% or higher). Lower grades may potentially leave residues on the film.
What might a tiny amount of wetting agent do that is likely to result in problems and what might those problems be? I am simply looking for info. I have never had the OP problem and have no axe to grind.
Thanks
pentaxuser
Foaming, which may cause development issues as seen in post #38.
No, don't do it! A surfactant might cause foam and IPA might extract needed chemicals from the film.
PE
- Joined
- Jul 31, 2012
- Messages
- 3,284
- Format
- 35mm RF
But I had used LFN for over two decades without a single problem. It was only with the new bottle of LFN that the problem happened, so you can only draw the conclusion that LFN now might cause problems, not that all wetting agents cause problems. The old LFN never caused problems. In fact it solved problems. No air bells.
Interesting. It seems that different wetting agents have different characteristics, hence my question about which to choose a few posts above. Or maybe some are more powerful in effect and might be ok if less were used.
- Joined
- Jul 31, 2012
- Messages
- 3,284
- Format
- 35mm RF
That is a good question, but I certainly don't have an answer for you. I'd love to know myself.
The MSDS for LFN changed from listing some alcohols I think (not a chemist) in 2009 to "trade secret" in 2015. I don't know what that means, but something had to change.
MattKing
Moderator
I have been musing on the interchange in this thread between PE and Andrew O'Neill.
I know Andrew makes good use of semi-stand techniques with sheet film.
Could it be that a reduction of surface tension is much more important in that context than in anything that involves "normal" agitation or roll film?
I know Andrew makes good use of semi-stand techniques with sheet film.
Could it be that a reduction of surface tension is much more important in that context than in anything that involves "normal" agitation or roll film?
Foaming is probably the major issue here Matt. Surfactants sometimes cause uncontrollable foaming, especially on contact with other surfactants. Films are loaded with surfactants.
PE
PE
Is there a real risk of this? Earlier in the thread you said it wouldn't have any significant impact on the film.
I will perform further tests as time allows, but the first trial run didn't show any artifacts I could discern.
Probably it would not, I really don't know, but why take a chance. Many of the chemicals we add before coating are dissolved in IPA.
PE
PE
Probably it would not, I really don't know, but why take a chance. Many of the chemicals we add before coating are dissolved in IPA.
PE
PE
IPA = isopropyl alcohol
Glad it worked. I regularly mix water with alcohol. The best alcohol and water mixture I have found is from Speyside in Scotland
It doesn't sound as if there were any other extraneous factors to have caused this so can we assume that it was simply the IPA and water and can anyone explain how this arises? 2C is quite a jump
Thanks
pentaxuser
Which of these are you recommending to add to the developer? I am waiting patiently at the store.
I add Guiness!
| Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links. To read our full affiliate disclosure statement please click Here. |
PHOTRIO PARTNERS EQUALLY FUNDING OUR COMMUNITY:  |