BnW reversal attempts

[YoIaMoNwater]

I don't have too much to add here, but I have sunk quite a number of hours into B&W reversal and I do have some suggestions for testing. It takes a lot of testing to get excellent results, and it's very easy to deceive yourself unless you expose some step wedges and measure them with a densitometer. Next best is to take identical exposures of the same scene under controlled lighting and directly compare the slides.

The experimentation can be simplified considerably by only changing the critical step: the first developer. All other steps can be considered to be "to completion", so as long as you have a working process and you maintain fresh solutions and good washes between steps, you just need to focus on the first development. If you can mix your own chemicals, I would suggest going for a tried and true formula, such as Ian Grant has posted here. Choose one developer, choose one film, shoot a test strip with several frames of the same scene at different exposures and develop it.

If the slides come out too dark, increase the FD time. If the Dmax is reduced, you've increased the time too much.

If the slides come out too bright, decrease the FD time. If the Dmin is increased, you've decreased the time too much.

If you cannot find a combination of exposure time and development time that gives an acceptable brightness without compromising Dmax or Dmin, you'll need to try a different developer composition or give up on that film and try a different one.

First developers are complex beasts and it is challenging to come up with your own formulation that will give excellent results that are backed up by densitometric data.

Since you mentioned it, if you are interested in Superpan 200, I can share the best results that I have obtained with this film.

Film: Superpan 200
FD: D67; 6 min at 20 °C
gamma = 2.6; Dmax = 2.8, Dmin = 0.1

View attachment 261044

View attachment 261043

Wow those look great! What kind of densitometer do you recommend/are you using?

 

[Raghu Kuvempunagar]

Film: Superpan 200
FD: D67; 6 min at 20 °C
gamma = 2.6; Dmax = 2.8, Dmin = 0.1

@iandvaag: Nice informative and educative work! Just curious to know how you computed gamma. 2.6 seems high as typically slide films aim at gamma of 1.7-1.8 IIRC.

 

[iandvaag]

Thanks Yola and Raghu. I hope my results can be helpful to anyone else trying to develop this film.

These measurements were taken on an Xrite 301. I don't know how the various models stack up. I've heard of some people using a scanner as a densitometer. I would think there's a bit of fiddling about to get proper calibration and override automatic adjustments, but I'm not really familiar with this method. I picked up the Xrite for not too much money, and never bothered to learn about the limitations of using a scanner as a densitometer.

If you need something measured, you're welcome to send me test strips and I can measure them for you on my densitometer. This offer goes to anyone doing reversal experiments.

I don't have a properly calibrated sensitometer, so I don't get film speed information out of this. I labelled the x-axis "relative log-E", but really it's just the density readings from the Stouffer step wedge. I develop the test strip taken at different exposures alongside the printed step wedge to get a rough idea of film speed.

The gamma was a linear regression on the straight line portion from 1.28 to 1.72 log-E. I would agree, the contrast is definitely a bit high by the numbers. The straight line gamma is not the whole story when it comes to contrast though. I've found that Delta 100 works well in D67 using a time of 15 minutes. Although it develops to essentially the same gamma using this time, the overall contrast to the eye appears lesser compared to the Superpan 200. I believe this reflects differences in the toe and the shoulder, and I need to make additional calculations such as contrast index or average gradient to quantify those differences. I would be happy if anyone has suggestions as to which types of calculations capture the differences of contrast seen by the eye. The Kodak sensitometry workbook is great, but if anyone has recommendations as to a book or paper with information on more advanced sensitometry, that would be awesome.

In the end, I was happy to get good Dmax and Dmin and I got tired of testing. So to date I haven't done any tweaking to the developer formulation which I believe is probably required to change the contrast while maintaining good Dmax and Dmin.

Best,
Ian

 

[Raghu Kuvempunagar]

If you need something measured, you're welcome to send me test strips and I can measure them for you on my densitometer. This offer goes to anyone doing reversal experiments.

This is very kind of you @iandvaag. Thanks also for explaining how you got gamma of 2.6. Much appreciated.

Regarding the gamma, the concern I've is it is computed from a straight-line part of the curve that corresponds to a relatively small exposure region, 1.28 to 1.72 log-E, which is about 1 stop. Had you considered the more useful exposure region 0.5 to 1.5 log-E (mid tones?), you would have got a gamma of ~1.75.

 

[iandvaag]

I agree with your assessment @Raghu Kuvempunagar. It would probably be more meaningful to report the average gradient over a longer portion of the curve since there is most certainly image data contained in the shoulder and toe of the curve. Even so, it is my understanding that the conventional number of 1.6 to 1.9 (as suggested by PE in his photo system engineering primer here) refers to the straight line portion of the curve. But straight line gamma is certainly not the whole story.

I haven't received any formal training in photographic theory, so I've tried to stick to the definitions that are given in the Kodak sensitometry workbook found here. I don't know if the definitions presented in that document are standard or not, but the following definitions are given:

Gamma (γ) - slope of the straight line portion of the curve

Average Gradient (Gbar) - average slope between any two points on the curve. The points chosen for the calculation should be specified when reporting the value.

Contrast Index (CI) - determined graphically, but essentially it measures the contrast of a negative in the exposure range that is normally used to make high-quality negatives.

Here is the raw data if you'd like to try calculate anything yourself:

Density of Stouffer step wedge	Density of Superpan 200 developed 6 min in D67
2.84	0.12
2.72	0.13
2.54	0.16
2.44	0.18
2.33	0.21
2.16	0.27
2.04	0.37
1.89	0.52
1.72	0.78
1.60	1.11
1.45	1.48
1.28	1.91
1.13	2.25
0.98	2.48
0.82	2.63
0.67	2.72
0.50	2.78
0.35	2.79
0.20	2.83
0.05	2.79

 

[YoIaMoNwater]

Thanks a lot for the info Ian. It seems like the quantitative part of film density is way beyond my scope and definitely something I'm going to learn more about.

Just to update everyone on my progress. Turns out my developer has gone bad. I tested some film leaders from Rollei Superpan 200, Fomapan 400, and Film Washi F with the same method I did as before with a longer bleach time (15 min 1st dev, 10 min bleach, 2.5 min clear, 2nd exposure, 15 min 2nd dev, 5 min fix). All of the film leaders came out white after bleaching but turned dark after the 2nd developer and even after fixing. I think this definitely means my developer has hit the hay. I'm waiting for another pack of Microphen to arrive this week. In the mean time I might just give 1:6.5 Rodinal a try from Jens Osbahr's protocol.

 

[Donald Qualls]

Yep. After first dev, a fogged leader should be black, and the bleach should render it clear.

 

[Raghu Kuvempunagar]

I agree with your assessment @Raghu Kuvempunagar.
Here is the raw data if you'd like to try calculate anything yourself:

Very interesting data @iandvaag! Thanks again. Do you have similar data for any Ilford films that you can share?

 

[YoIaMoNwater]

The fresh Microphen arrived the other day. I tried to make a 2x stock in 500 mL but couldn't get everything dissolved so I ended up making a 1.3x stock in 750 mL. Next, I tested film leaders from Rollei Superpan 200 and Fomapa 400 with this more concentrated developer. The protocol was as usual but with different bleaching times (15 min 1st dev, 5 min and 10 min bleach, 2.5 min clear, re-exposure, 15 min 2nd dev, 5 min fix, 1 min stab). I mixed the KMnO4 bleach solutions (KMnO4 in part I and H2SO4 final in part II to get 1.5% final H2SO4) right before using it.

The 5 min bleach wasn't enough but 10 min seems to be better. I actually saw some silver "flakes" floating on top of the bleach solution and was afraid the emulsion might have fallen off. Since I already had parts of the Fomapan 400 from before (I accidentally cut the film off too early from the reel), I used the 10 min bleach step to see whether or not the emulsion is fine.

I like to mention that the top strip is from the fresh 1.3x Microphen whereas the bottom strip was from the first reversal attempt using a depleted Microphen from 2018.

Then I took a beer break for about 9 hours. I tested the bleaching again with a Rollei Superpan 200 film leader just to make sure it's still functioning. Unsurprisingly, 10 min did not completely clear the leader but 12 min did. I then developed a roll of Superpan with a 15 min bleach just to make sure.

@Raghu Kuvempunagar @Donald Qualls @Alessandro Serrao @destroya @Lachlan Young @iandvaag What do you guys think?

 

[iandvaag]

@Raghu Kuvempunagar Yes, I had a good result with Delta 100 and some poor results with HP5 and PanF. I've been pretty busy lately, but I'll try to post the details this weekend.

 

[YoIaMoNwater]

Scans from plustek 8200i

 

[Raghu Kuvempunagar]

@Raghu Kuvempunagar Yes, I had a good result with Delta 100 and some poor results with HP5 and PanF. I've been pretty busy lately, but I'll try to post the details this weekend.

@iandvaag: sure, no urgency, please post when you make yourself free. As far as I'm concerned, the data you've posted is among the stuff I've found most useful in threads like this and I look forward to seeing more such data.

 

[iandvaag]

@YoIaMoNwater It looks like you're getting some nice results, congrats. I'm not sure exactly what you wanted a comment on, but here are a few thoughts:

Good idea about mixing the permanganate bleach fresh. In aqueous solution, MnO4- spontaneously reduces to MnO2 which further catalyzes the reaction. MnO2 is a brown sludge which can stain your film. You didn't mention what your clearing bath is, but IIRC Haist recommends a metabisulfite solution since its lower pH will help solubilize the MnO2. Some of the excess density you see may be owing to stain rather than incomplete bleaching, hard to say for sure. Wash well before and after the bleach. I recommend distilled water for the bleach. Permanganate will soften gelatin, so you'll want to use a film that is well hardened and minimize the time in contact with the bleach. I can attest that the hardeners used by Ilford and by Foma are not the same.

10 minutes in dichromate bleach seems long, and it doesn't look like it went to completion.

As for using old developer, I wouldn't chance it. Your time is worth more and it will be difficult to replicate if you do achieve successful results.

I use Dektol/D72 for the 2nd developer which only needs 4 minutes max. Reducing the total time of the process frees up time to do further experiments.

@Raghu Kuvempunagar Thanks for your interest. I'm glad someone else might be able to make use of my results. I posted these results on APUG once before, but there wasn't much interest. I've been meaning to do a proper write-up and put it on my website or maybe the "Resources" section here, but I haven't gotten around to it.

The only Ilford film that I managed to get good results with was Delta 100. I have "failed" results for other films, but I won't clutter up this thread with those results. I do think it's important to report failures, so I'll plan to write this up and post it somewhere. I didn't manage to find a great result for the following films using D67 and varying the developing time: Delta 400; PanF+; Tmax 100; Tmax400.

Film: Delta 100
FD: D67; 15 min at 20 °C; continuous rotary agitation in Jobo CPE-2
gamma = 2.7; Dmax = 3.57, Dmin = 0.33

Density of Stouffer step wedge	Density of Delta 100 developed 15 min in D67
2.84	0.33
2.72	0.35
2.54	0.37
2.44	0.41
2.33	0.46
2.16	0.50
2.04	0.54
1.89	0.59
1.72	0.64
1.60	0.71
1.45	0.80
1.28	0.94
1.13	1.14
0.98	1.44
0.82	1.86
0.67	2.27
0.50	2.72
0.35	3.14
0.20	3.43
0.05	3.57

 

[relistan]

Scans from plustek

These look really nice! Second from the top looks like the right exposure to me.

 

[Raghu Kuvempunagar]

@iandvaag: thanks so much for sharing the data on Delta 100.

I was wondering why longer development resulted in lower DMax but it had skipped my mind that D-67 has thiocyanate in it! Do you use D-67 as single use first developer or do you use it several times till you notice a significant difference in the results?

Let me take some time to digest the data and come back to you with questions or comments. I'm sure I'll have a few.

Yes, a blog post on other films you have tried would be very useful for me at least.

 

[YoIaMoNwater]

@YoIaMoNwater It looks like you're getting some nice results, congrats. I'm not sure exactly what you wanted a comment on, but here are a few thoughts:

Good idea about mixing the permanganate bleach fresh. In aqueous solution, MnO4- spontaneously reduces to MnO2 which further catalyzes the reaction. MnO2 is a brown sludge which can stain your film. You didn't mention what your clearing bath is, but IIRC Haist recommends a metabisulfite solution since its lower pH will help solubilize the MnO2. Some of the excess density you see may be owing to stain rather than incomplete bleaching, hard to say for sure. Wash well before and after the bleach. I recommend distilled water for the bleach. Permanganate will soften gelatin, so you'll want to use a film that is well hardened and minimize the time in contact with the bleach. I can attest that the hardeners used by Ilford and by Foma are not the same.

10 minutes in dichromate bleach seems long, and it doesn't look like it went to completion.

As for using old developer, I wouldn't chance it. Your time is worth more and it will be difficult to replicate if you do achieve successful results.

I use Dektol/D72 for the 2nd developer which only needs 4 minutes max. Reducing the total time of the process frees up time to do further experiments.

@Raghu Kuvempunagar Thanks for your interest. I'm glad someone else might be able to make use of my results. I posted these results on APUG once before, but there wasn't much interest. I've been meaning to do a proper write-up and put it on my website or maybe the "Resources" section here, but I haven't gotten around to it.

The only Ilford film that I managed to get good results with was Delta 100. I have "failed" results for other films, but I won't clutter up this thread with those results. I do think it's important to report failures, so I'll plan to write this up and post it somewhere. I didn't manage to find a great result for the following films using D67 and varying the developing time: Delta 400; PanF+; Tmax 100; Tmax400.

Film: Delta 100
FD: D67; 15 min at 20 °C; continuous rotary agitation in Jobo CPE-2
gamma = 2.7; Dmax = 3.57, Dmin = 0.33

View attachment 261577

View attachment 261579

Density of Stouffer step wedge	Density of Delta 100 developed 15 min in D67
2.84	0.33
2.72	0.35
2.54	0.37
2.44	0.41
2.33	0.46
2.16	0.50
2.04	0.54
1.89	0.59
1.72	0.64
1.60	0.71
1.45	0.80
1.28	0.94
1.13	1.14
0.98	1.44
0.82	1.86
0.67	2.27
0.50	2.72
0.35	3.14
0.20	3.43
0.05	3.57

Thanks for the advice Ian. Yea I think the main issue was the developer. I have couple rolls of HP5+ pushed to 3200 and 6400 that I'm gonna try with the current protocol with a increased time for the first dev step.

These look really nice! Second from the top looks like the right exposure to me.

Thanks a lot man! It definitely seems like +1 for this film is the ideal exposure for reversal.

 

[DeletedAcct1]

Thanks for the advice Ian. Yea I think the main issue was the developer.

Why you don't try Ilford PQ developer?

 

[YoIaMoNwater]

Why you don't try Ilford PQ developer?

I wanted to see if Microphen could be used for reversal because I have couple rolls of HP5+ at 3200 and 6200. Thought might as well try these for reversal so I gave this developer a try.

 

[Eddypolak]

My story so far....After some experimentation I have gotten decent results for B&W reversal using Scala 160 using the process published by Ilford. Ilford recommend PQU 1+5 with 8gm/l of sodium thiosulphate. I use that mixture and my best results are +1 stop overexposure and 10 minutes FD time. To me the results are OK but contrast is a little low. I hesitate to mention 'contrast' because I am not sure if I should just say 'blacks are not very black'! I only have my subjective view not having any lab kit to measure the film objectively.

I know that if I run FD for 12 mins (what Ilford suggest as a starting point) the resulting film is very thin indeed. Before I try another roll with an FD time of say 11 mins as an obvious next step I wonder if there is something worth trying regarding adjusting the sodium thiosulphate concentration. I really don't understand the purpose of this component and what image parameter you might control by adjusting it. My other thought/question is whether adjusting the concentration of PQU is worth exploring.

In short I have come to a point where I don't understand enough to be able to take the next steps in an intelligent way so any help would be appreciated!

 

[relistan]

My story so far....After some experimentation I have gotten decent results for B&W reversal using Scala 160 using the process published by Ilford. Ilford recommend PQU 1+5 with 8gm/l of sodium thiosulphate. I use that mixture and my best results are +1 stop overexposure and 10 minutes FD time. To me the results are OK but contrast is a little low. I hesitate to mention 'contrast' because I am not sure if I should just say 'blacks are not very black'! I only have my subjective view not having any lab kit to measure the film objectively.

I know that if I run FD for 12 mins (what Ilford suggest as a starting point) the resulting film is very thin indeed. Before I try another roll with an FD time of say 11 mins as an obvious next step I wonder if there is something worth trying regarding adjusting the sodium thiosulphate concentration. I really don't understand the purpose of this component and what image parameter you might control by adjusting it. My other thought/question is whether adjusting the concentration of PQU is worth exploring.

In short I have come to a point where I don't understand enough to be able to take the next steps in an intelligent way so any help would be appreciated!

I think you are probably both running the first developer too long and also using too much thiosulfate. Ilford's recipe really uses a lot!

I am not using the permanganate bleach, but my best results with ADOX Silvermax/Scala 160 were with 3g/L sodium thiosulfate and 10 mins in my first developer. I am using Ilford Multigrade 1+5 instead of PQU 1+5 but I expect the difference will be minimal. I also discovered that, at least in my experience, Ilford's recipe does not run long enough in the 2nd developer if I use less thiosulfate. So I run 8 minutes in the second dev (Ilford Multigrade 1+9).

My notes suggest that I thought maybe 1 less minute in first dev would be better for the next attempt (which was not happened).

 

[Eddypolak]

Thanks for that really helpful reply!

To give a little more detail, my first half way decent results were with 8 minutes FD but with +3 stops overexposure. I wanted to get away from such a low effective ASA though and the results are better with my current combination in terms of darker blacks. What exposure did you use to get your best results? As I am now running 10 mins FD like for your best results I wonder if it's my initial exposure that's different.

Are you able to explain the effect of the thiosulphate on the image? I am happy to reduce the quantity based on your advice but it would be good to know what's going on there.

I didn't mention my 2nd developer because I am confident it's running to completion. I run Ilfosol 3 (1+9) for 8 minutes. I ran a test for 5 minutes to start with but then opened up the tank and put the film in a bowl with the developer. It darkened a little after a couple of minutes but that was it.

If you wonder why Ilfosol 3 it's because in earlier experiments with Pan F Plus completely following Ilford I found that the emulsion was dramatically softened add came off in places. After the bleach and clear it was fine so I tried the only other developer I had for 2nd development. All went well so I have stuck with it.

 

[relistan]

Thanks for that really helpful reply!

No probs!

To give a little more detail, my first half way decent results were with 8 minutes FD but with +3 stops overexposure. I wanted to get away from such a low effective ASA though and the results are better with my current combination in terms of darker blacks. What exposure did you use to get your best results? As I am now running 10 mins FD like for your best results I wonder if it's my initial exposure that's different.

I shot 5 frames on that mini roll at +1, +1/3, 0, -1, and -2 and it looked best at 0 which is 160 ISO.

Are you able to explain the effect of the thiosulphate on the image? I am happy to reduce the quantity based on your advice but it would be good to know what's going on there.

You are trying to dissolve some of the silver halides from the film in order to make sure that you develop _all_ the exposed halides and that the highlights end up nearly clear. The alternative strategy used by Agfa in the Scala process is to add development accelerators that allow the developer to be even more aggressive and get into all the silver. Those accelerators are not that well understood in this process and not that easy to come by. So we mostly experiment with the older strategy of thiosulfate or thiocyanate solvents.

The thing that causes Dmax (blackest blacks) to not be good is either fogging by the first developer (running it too long will do that), or dissolving too much of the halides in the non-highlight areas because you are using too much solvent. So that's why I recommended that I think you are running it both too long and also using too much solvent. You didn't mention the state of the highlights but if they are OK, then you may see a little less clarity after trying this and you'll have to tweak it with more trials, changing a variable at a time.

I didn't mention my 2nd developer because I am confident it's running to completion. I run Ilfosol 3 (1+9) for 8 minutes. I ran a test for 5 minutes to start with but then opened up the tank and put the film in a bowl with the developer. It darkened a little after a couple of minutes but that was it.

If you wonder why Ilfosol 3 it's because in earlier experiments with Pan F Plus completely following Ilford I found that the emulsion was dramatically softened add came off in places. After the bleach and clear it was fine so I tried the only other developer I had for 2nd development. All went well so I have stuck with it.

That sounds fine to me! The second developer is not that important as long as it's to completion.

 

[Raghu Kuvempunagar]

my first half way decent results were with 8 minutes FD but with +3 stops overexposure.

Scala 160 is meant to be exposed at box speed. If you're having to give 3 stops more exposure, your first developer is not strong enough or you're not developing long enough. Note that the data sheet of Adox's Scala reversal kit recommends a rather long development time of 15 minutes at 24C despite the supposed use of a development accelerator in its first developer. Try cutting down thiosulphate and increase the development time.

 

[Eddypolak]

That is the best explanation by a mile of the first development process in reversal I have read anywhere especially regarding the role of the thiosulphate. Thank you very much!

I will now consider my next move but getting back to 160 ASA is appealing!

Stay safe!

 

[Eddypolak]

In reply to Raghu....

Thanks for the advice and info!

That's interesting to know about Scala 160. On my first attempt with it I followed the Ilford process including the 12 min development time as as starting point. When it came out as virtually clear acetate I went the wrong way and tried over exposure and found a balance by shortening the development time. It looks like time for a reset and stick to 160 ASA adjusting my process to suit.