Rollei RPX practical questions

tho60

tho60

Well-known
Local time
11:14 PM
Joined
Jul 16, 2010
Messages
309
Hello,

in addition to Fomapan films I will buy a bulk of Rollei RPX 25 film. I have heard that this film has some troubles.

1. Slow films, like Rollei RPX 25 have very narrow latitude so steering the contrast is a quite hard task. Either darks are without details or high-lights are blocked. How to solve this problem?
2. Rollei RPX 25 has Polyester base which, like fibre-optics shows in light into the canister, causing light leaks. How to avoid this problem?


Thanks, Thomas
 
Use a lower contrast type developer or semi-compensating type, often a two bath.
Load and unload the 35mm film in subdue light. Keep the 120 roll film tight on the spool and directly close and glue it when finished. A Black cannister 35mm or for roll film will help too.

The same you have to do with the Rollei Retro 80(S), (S)uperpan 200 and the Retro 400(S), all (S)ynthetic based. Clear Polyester layer, even all 100um thin E1. Aviation type film from Agfa Gevaert, Aviphot 80 E1 and Aviphot 200 E1. Superpan 200 and Retro 400(S) are both the same emulsion. In most developers iso 160 only. Retro 80(S) iso 50-64 in general.
 
I will have difficulties with two-bath developing, I mean that this method is more suitable for trays. My idea is using very diluted Rodinal, but there is a minimum amount of developer for each film. Or using Perceptol to emphasize fine grain, but this might lead to speed loss.
Is subdued light enough, or a darkroom required?
 
I am only shooting 35mm preloaded. But, I have never had a problem with the polyester film working as a waveguide. I am sure that it does happen, but I just load in subdued light and it hasn't been a problem.
 
developer

developer

Which developer should I prefer: Perceptol or Rodinal? If Rodinal, what dilution?
 
R09/Rodinal is working in the surface and gives a very sharp negative. Perceptol is an ultra fine grain developer which gives more speed loss but also less sharpness however you can compensate this by diluting more and bring the concentrate Sodiumsulfite down. It is just a matter of taste. Further with R09/Rodinal you will have a sharper S-curve so quicker burned out high lights. Good results with Retro(S) films and RPX-25 you can achieve with CG-512/Rollei Low Speed (RLS) an Udo Raffay receipt working on 24C in rotary too. Also A-49 seems to work fine too in a 1+1 or 1+2 dilution. Many possibilities.
 
first pictures

first pictures

I have loaded some film into cassette and shot some pictures. My conclusion is that the factory data for developing are correct. At first I followed instructions read on the Internet, these were misleading.
I used home-made Parodinal, 1:50 dilution, 11 minutes with agitation.
 

Attachments

  • IMG_0012.jpg
    IMG_0012.jpg
    41.4 KB · Views: 0
Fotohuis said:
What is your recept for Parodinal?
Click to expand...

I have contacted Martin Zimelka and he wrote me the following formula:
[FONT=Helvetica,Arial]Volume target: 1000ml[/FONT]
[FONT=Helvetica,Arial]Paracetamol: 75.6 gr (pure powder)
[/FONT]
[FONT=Helvetica,Arial]Sodium Hydroxide: 127.3 gr
[/FONT]
[FONT=Helvetica,Arial]Potassium Metabisulphite: 175.8gr[/FONT]
 
Fotohuis said:
You do not have a problem with dissolving such an amount of Paracetamol?
Click to expand...

I had some troubles, but not due to dissolving paracetamol. I mixed 1.33 litres instead of 1 litre because I purchased 100 grams of paracetamol and modified the amounts accordingly. My main problem is that much more precipitation has occurred than I expected.
When I decanted the solution I noticed that the amount of water was measured wrongly. About 1.1 litres instead of 1.33 litres. So I added some more water and this worked perfectly.

Here is the mixing method (by M. Zimelka):

Use two small volumes of distilled water, around 250ml each.
Heat the one portion in a microwave until warm/hot. Ad the sulphite, but leave a small pinch of it for the second portion.
To the second portion, ad the pinch of sulphite, then ad the Hydroxide. Once hot and dissolved, ad the paracetamol, and stir well.
Once Hydroxide solution is mixed, ad it to the Sulphite portion, and then fill to make a total of 1000ml. Stir well.
Bottle the final solution in an air tight bottle, preferably glass, and let it cure for 3 days.
Any impurities from your ingredients will have settled at the bottom, and then you'll be able to decant most of the Parodinal. Its not worth filtering, and the best way is to simply decant and chuck the rest away.
 
Personally I have never had much success with the RPX line of films, but perhaps it is due to the misleading information on the internet regarding developing. The polyester substrate = very flat negatives (good) but I found the film's latitude and grain to be unattractive (bad).

I think I still have a few rolls in my fridge, perhaps I will try RPX again. Thank you for sharing this developer recipe.
 
Personally I have never had much success with the RPX line of films, but perhaps it is due to the misleading information on the internet regarding developing.
Click to expand...

RPX-400 E.I. 400 in the new ATM-W 20 minutes at 22C in rotary (Jobo CPA-2). Full iso 400 speed. Zorki-6 with J-9:

23238813953_c4d0067510_c.jpg


Fomaspeed Variant 311, Split Grade print G=2,2. ID-78 1+1 paper developer, (Svema, "made in Ukraine").
 
The recipe calls for pure paracetamol (not the tablets with filler) and then says to let any impurities settle. A contradiction?
I would have trouble getting the more soluble potassium metabisulphite.
Still, it's a nice formula to keep. Thank you Tho60.


Fotohuis said:
How many headache pills you have to dissolve, a whole 20 packet? :) or more ...... ;)
Click to expand...
 
Indeed, while the original idea was to use headache tablets. If there are still impurities with pure Paracetamol what is the win win situation then?

Dissolving any Hydroxide will lead to a much higher temperature (exotherm) of the water and vapor which is dangerous and toxid to inhale.

To those who want to experiment with Rodinal type, for 100ml:

15ml destilled water
75ml Potassiumsulfite (45%, 450g/l)
5,5g para- Amino Phenol (no HCl)
4,0g Potassiumhydroxide
1,0g Potassiumbromide
2,0g EDTA-4Na
fill up till 100ml
Alternative:Instead of EDTA-4Na you can use Fotoplex1, fill up till 100ml.

The original R09 is more difficult to prepare and without experience also not without any risk.
 
Last edited:
Re-reading the OP's formula it does say to heat the 1st solution but the 2nd will get hot by just adding the NaOH. In this case 12,5g/100ml.
I note your formula calls for 75ml Potassiumsulfite (45%, 45g/l) and I have trouble with this. 45% is 450g/l not 45g/l. I presume it's the latter. How much of the dry sulohite is it? I would have to reconfigure it for the Sodium salt which is all I have access to.
EDTA-Na is unobtainium in Australia AFAIK. Is it really necessary?

Thanks for your input.


Fotohuis said:
Indeed, while the original idea was to use headache tablets. If there are still impurities with pure Paracetamol what is the win win situation then?

Dissolving any Hydroxide will lead to a much higher temperature (exotherm) of the water and vapor which is dangerous and toxid to inhale.

To those who want to experiment with Rodinal type, for 100ml:

15ml destilled water
75ml Potassiumsulfite (45%, 45g/l)
5,5g para- Amino Phenol (no HCl)
4,0g Potassiumhydroxide
1,0g Potassiumbromide
2,0g EDTA-4Na
fill up till 100ml
Alternative:Instead of EDTA-4Na you can use Fotoplex1, fill up till 100ml.

The original R09 is more difficult to prepare and without experience also not without any risk.
Click to expand...
 
You must log in or register to reply here.
Back
Top Bottom