Emulsion for reversal processing

[psykodaddy]

Hey photo folks

For months I'm trying to mix my own emulsion for reversal processing on paper...by now with partial success only.

I hope some of you can make out the mistake in my process or point of view

Today I've tried my third emulsion, all of them with nearly the same results...first emulsion was derived from Abney, second my own creation and third was AJ-12.

Here comes my workflow:

-I've prepared an emulsion strictly according to Kodak AJ-12

-Added chrome alum solution prior to coating with a Meyer rod (4 mil) on glass (2 mm) and paper (400 g/m2)

Paper was processed (good quality watercolor paper from Hahnemühle):

#1st Dev Ilford MG Paper dev - 90 sec
#Bleach Kodak R9 - 60 sec
#Clearing was 5% solution of sodium sulfite - 60 sec
#Re-exposure - 60 sec
#2nd Dev Ilford MG Paper dev - 90 sec

Rinse between each step


Glass was processed (nearly according to Kodak specs for reversal of TriX):

#1st Dev Kodak D-94 - 2 min
#Bleach Kodak R9 - 3 min
#Clearing was 5% solution of sodium sulfite - 3 min
#Re-exposure - 60 sec each side
#2nd Dev 777 - 3 min

Rinse between each step


The results:

-Glass turned out as a pretty good positive

-Paper was completely black (commercial paper makes nice positives with the very same process)


So, the process seems to be wrong for the paper...or am I missing something?

Does someone have a clue why???

I'd say it's developer or bleach...

Maybe @dwross has something to share Would be an honor!

Thanks for your time and effort with me!

Greetings from good old Germany

 

[revdoc]

Usually, if the reversed image is too dark or black, either first exposure is too short, or first development is too short, or both. Reversal requires that exposure and first development together almost exhaust the halides in the highlights, so that after bleaching, only a little halide is left. Re-exposure and second development will produce slight tone in those areas.

In your case, I'd try exposing a test strip, with increments of 1 stop, to see if you get an image. Increasing first development time would probably help, too, but it's better to change one thing at a time.

 

[koraks]

So, the process seems to be wrong for the paper...or am I missing something?

Sorry, no direct experience here, but I'm puzzled by the fact that you have the exact same emulsion on both paper and glass, but you treat it completely differently in both instances. Have you tried the obvious option of processing your paper in the same way as your glass plates? I'd expect there to be some difference due to the permeability of the paper base, but since it's still the same emulsion, it would seem to me that you'd get fairly similar results from both materials if it's the same emulsion.

 

[psykodaddy]

Sunny Sunday over here, perfect for some tests...if I'd have some more coated stuff

Usually, if the reversed image is too dark or black, either first exposure is too short, or first development is too short, or both. Reversal requires that exposure and first development together almost exhaust the halides in the highlights, so that after bleaching, only a little halide is left. Re-exposure and second development will produce slight tone in those areas.

In your case, I'd try exposing a test strip, with increments of 1 stop, to see if you get an image. Increasing first development time would probably help, too, but it's better to change one thing at a time.

Yeah, that's a good idea! I forgot to mention the plates and papers were all exposed with a step wedge ISO 0.8 + 1.6 + 3 + 6

For commercial papers it works...but do you think the Ilford MG dev is not the correct soup to do the halide job?

Sorry, no direct experience here, but I'm puzzled by the fact that you have the exact same emulsion on both paper and glass, but you treat it completely differently in both instances. Have you tried the obvious option of processing your paper in the same way as your glass plates? I'd expect there to be some difference due to the permeability of the paper base, but since it's still the same emulsion, it would seem to me that you'd get fairly similar results from both materials if it's the same emulsion.

AFAIK we should never ever use film dev for paper...I've had a try with that some time ago and the paper turned out to be fully black after a short time only...

Maybe a dilution of the first dev could help!?


It's still a mystery to me. Today I'll coat some more paper to run more tests. Appreciate your input for the next ones

Enjoy your Sunday over there guys!

 

[koraks]

AFAIK we should never ever use film dev for paper

What's the rationale, though? It's the same emulsion, isn't it? Just a different base?

I understand that 'common lore' suggests to use a film developer for film and a paper developer for paper, but that's within the assumptions that the paper is used to make regular prints on, that the paper is a different emulsion in several ways than a film emulsion, and that the requirements on tonal scale and maximum density are wildly different between the two. Furthermore, there's the issue that it's perfectly possible to use a paper developer for film, and even vice versa, and that this is being done by many people, sometimes routinely. So I wouldn't attribute too much weight to 'rules' like this one, especially if you're doing something that's pretty far off the beaten path.

 

[psykodaddy]

@koraks thanks for the bump into the right direction! Changed my point of view Beaten paths are not for me...

I'll coat some today and then will definitely run a test these days! Will keep you updated!

Another way: I'm pretty well equipped with chemicals and can mix a whole lot developers from scratch.

Can someone suggest a developer working the right way, maybe from own experience?