sevo
Fokutorendaburando
I would have expected Tetrasodium EDTA to be the most easily obtainable chemical in there second to KOH. EDTA sodium salts are the most common chelators, used in large amounts for medical and technical purposes, in food processing, cosmetics and aquaristics - there probably will be some place in driving distance selling it by the 50 pound bag. Disodium EDTA should be a good substitute - IIRC it buffers to a different pH in aqueous solution, but that can't matter in such a strong potassium hydroxide solution.
Murray Kelly
Well-known
You would think so but Brisbane is not a city with heavy industry. I have looked and given up. Unbelievably, almost, they manufacture TEA from natural gas in the port area and the smallest size they sell is 200L.
sevo
Fokutorendaburando
Well, if there really is nothing to be had, you should be able to order it abroad, many ebay sellers ship it, e.g. http://www.ebay.de/itm/Tetrasodium-...882325?hash=item3ca4339795:g:IiYAAOSw-7RVGirY - it is neither hazardous nor controlled. Disodium EDTA positively is obtainable in Australia, a minute of googling brought up http://shop.newdirections.com.au/ep.../Shops/newdirections/Products/RMAA100EDTADISO
If you use distilled water and all components are p.a. pure and free from heavy metals, you might do without a chelator - that is presumably all it is used for, at any rate I have never read anything which would lead me to believe that the mild reducing and inhibiting properties of EDTA are exploited in Rodinal. But in general EDTA makes home-made developers considerably more predictable and well-behaved - traces of calcium, manganese and iron (from the well) and copper (from household tubing) well below the legal thresholds for drinking water can already render some developing agents ineffective or alter their behaviour...
If you use distilled water and all components are p.a. pure and free from heavy metals, you might do without a chelator - that is presumably all it is used for, at any rate I have never read anything which would lead me to believe that the mild reducing and inhibiting properties of EDTA are exploited in Rodinal. But in general EDTA makes home-made developers considerably more predictable and well-behaved - traces of calcium, manganese and iron (from the well) and copper (from household tubing) well below the legal thresholds for drinking water can already render some developing agents ineffective or alter their behaviour...
Murray Kelly
Well-known
Thank you, thank you, Sevo. (Used it for 20 years.) No, seriously, that is a most useful link. They are a 1000km away but the postal service would be OK for most stuff.
I tend now to make developers with one of the glycols and no water. I even bought 5L of TEA from a supply house only to find it was the low freezing stuff which has 15% water in it. Quite useless for concentrates and metaborate has a pretty close pH anyway.
If I use water for anything, like the final developer, then I use de-ionised water from the local hardware store. The tap water here is pretty good in fact.
I have bookmarked the page for my future reference.
I tend now to make developers with one of the glycols and no water. I even bought 5L of TEA from a supply house only to find it was the low freezing stuff which has 15% water in it. Quite useless for concentrates and metaborate has a pretty close pH anyway.
If I use water for anything, like the final developer, then I use de-ionised water from the local hardware store. The tap water here is pretty good in fact.
I have bookmarked the page for my future reference.
tho60
Well-known
Yes, I have followed an advice which told me that 1:120 dilution (R09), 14 minutes, 18 Celsius are the best dev. factors; but these resulted in botched negatives, hardly visible. I missed some very good frames.
Fotohuis
Well-known
High iso speed films and R09/Rodinal in 35mm is a waste of effort and try. So for Rollei RPX-400 (coming from Harman/Ilford) you can better try something else.
Apologize for the typo. 1%=10g/ltr. So 45% is 450g/ltr. of course.
About the EDTA everything is already said. When using distilled water you won't need it however above receipt is an old Calbe / Agfa East Germany profile hence the extra ingredient which will work world wide with less good tap water too.
Apologize for the typo. 1%=10g/ltr. So 45% is 450g/ltr. of course.
About the EDTA everything is already said. When using distilled water you won't need it however above receipt is an old Calbe / Agfa East Germany profile hence the extra ingredient which will work world wide with less good tap water too.
tho60
Well-known
Rollei RPX with ST-2
Rollei RPX with ST-2
I have developed a test roll of Rollei RPX 25 with ST-2. The results were excellent.
Rollei RPX with ST-2
I have developed a test roll of Rollei RPX 25 with ST-2. The results were excellent.
Fotohuis
Well-known
I would be interested in the result. RPX-25 has also a steep developing curve. The film looks like an Aviation type film, Clear layer, both 135-36, 120 roll film and even the sheet film on 100um Polyester.
Here my result with RPX-25:
tho60
Well-known
I would be interested in the result. RPX-25 has also a steep developing curve. The film looks like an Aviation type film, Clear layer, both 135-36, 120 roll film and even the sheet film on 100um Polyester.
Here my result with RPX-25:
When I will able to get scanned the negative, I will show examples immediately. Sorry, but I am renovating my rooms and you should wait for some weeks. I developed the film for 6 minutes and the negatives looked very fine, sharp and contrasty.
Fotohuis
Well-known
Renovating rooms .... I know what you mean: One to go! (But all my computer connections are there) so you can imagine my problem already. 
tho60
Well-known
Renovating rooms .... I know what you mean: One to go! (But all my computer connections are there) so you can imagine my problem already.
Here you are the pictures. Excellent sharpness & resolving power, but quite high contrast. I shoot the pictures with my Zorki-6 seen in my avatar picture.
Attachments
Fotohuis
Well-known
I think it is OK. Did you develop with R09/Rodinal or Parodinal or did you use the CT-2 (ST-2) Svema film developer?
tho60
Well-known
I have used ST-2 developer, 6 minutes developing time, 30 second agitation at the beginning, and then 10 seconds in every minute.
Danlo
Established
GAARGH!! I logged in to rangefinder forum and wrote a looong text in this thread about my experience with RPX400 and when I clicked "Post quick reply" it said that I was not logged and everything disappeared! BAAAH! Okay, here goes again, the short version: I have shot about shot 15 rolls of RPX400 and developed in Xtol 1+1 20C and it has the most ugly and obtrusive grain I have ever seen! It looks horrible even at 13x18cm small prints! The grain is sharp and looks a little like an over-processed high iso jpeg! The greyscale is okay, but the weird grain just destroys every image! Horrible! A full body portrait with some sky above in 13x18 cm looks like the face of the person is falling apart in pile of uneven graininess! So, my recommendation is: DO NOT WASTE YOUR MONEY ON THIS FILM! Thankyou
HHPhoto
Well-known
Rollei RPX 400 is just re-labeled Kentmere 400 film. But as Rollei it is much more expensive.
And RPX 100 just re-labelled Kentmere 100 film. Again more expensive than Kentmere 100.
And RPX 25 ist just re-labelled Rollei Retro 80S. Again at a higher price.
Therefore using the RPX line instead of the original films makes no sense.
Cheers, Jan
miha
Established
All probably true unless one needs to look outside of the 135 realm.
Freakscene
Obscure member
Murray, I am sorry it's taken me so long to see this. Sigma and other scientific suppliers sell NaEDTA in Australia in amounts of 50g-5kg, and will deliver.
Photo grade chemicals, specifically meta/bi/sulfites and other alkaline agents have enough Ca and Mg as impurities that you need it even if your water good.
And in parodinal and similar formulae, the filler in paracetamol tablets is usually a calcium salt.
Marty
Murray Kelly
Well-known
Thanks, Marty. I actually got some from Melbourne. I try to make up concentrates in glycol or similar but the idea of chelates etc is a deterrent to me now. It's there if I ever need it.
Murray
Murray