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Ilfochrome processing for the home/photoclub amateur
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B&W Dry Runs
Since I was unfamiliar with most of the equipment used for Ilfochrome processing, I decided to spend some time with B&W dry runs of the process. This helped me figure out many steps and also taught me how to do these steps in total darkness. I cut B&W paper to size, placed it under the enlarger, enlarged random negatives or slides on the strip and placed it into the print drum, then ran it through the regular B&W process.
I practiced running the process in a fully repeatable fashion, every step at a controlled temperature for an exact time frame. How long does it take to change from one bath to the next with this drum processor? How long does it take the processor to reach its set temperature? How much chemistry is the bare minimum? Can I do some tasks while the bath is active which could save time later in the process? How to I prepare exposure series in total darkness? Where do I place items so I can find them when I need them in the dark?
Some folks may be natural talents, others may already be experienced from RA4 printing. I am neither so I spent an evening in the dark room performing these dry runs until I was confident I could to all these steps reliably with Ilfochrome sheets. Fortunately all the hazardous steps can be done in day light, especially those steps involving the (nasty&smelly) Ilfochrome chemistry.
Exposure Settings
Since batches of Ilfochrome sheets have slightly varying color balance, a label on the box/envelope gives printers initial filter setting to start with. Once you switch from one batch to the next, and if you keep the rest of the process constant, you can guestimate the new filter values by subtracting the filter values printed on both batches and adding the difference to your last actual filter settings (which may be quite different from the values printed on the box).
With this information we can dial in initial filter settings, but we still don't know about exposure. Not only that I did not find anything useful online, the bigger problem is that different slides may differ in mid tone density by quite a bit, sometimes because of less than perfect film exposure, other times because different slide films have different contrast. So every time I switched slides I took a measurement with my density meter (since you only need to know the difference in densities, a simple light meter could probably be used here if you don't have a density meter for your enlarger).
Since Ilfochrome CLM.1K paper has a contrast of about 1, any difference in paper exposure will be faithfully reproduced by the paper. This allowed me to accurately nail Ilfochrome exposure reliably for very different slides with the density meter. I may have been hysterical about this, but I have read multiple reports about nasty reciprocity failure of Ilfochrome paper. In order to avoid running into this issue even after changing sheet format, I tried to cover most of the calculated exposure difference with the lens aperture and changed exposure time only to cover the small remaining difference.
Anyway, there is no substitute for an exposure series. Since we can run several test strips per dev run with little extra cost, it might well pay off to run fine grained exposure series, chances are high we nail exposure right after the first test run. So there we have it: we know optimal exposure from the test run and once the test strip has been fully washed and dried, we can see whether we need to correct color balance. This is most likely the case since color balance depends on process parameters and chances are the paper maker ran with different parameters than what you will use.
Color Balance
After establishing correct exposure settings I went on to achieve correct color balance. The most difficult aspect of this is that it takes so long to find out how the color balance came out. Remember, you need to let the paper dry completely before you start judging its colors. Since we want to do the absolute minimum number of test runs, I recommend you expose several sections of your test strip with different filter settings, starting with the filter settings printed on the box of the paper stash. If necessary, make multiple test strips, as long as you can fit them in the same drum.
Be sure you know what the filter settings on your color enlarger head really do. Magenta looks a lot like red to my eye, but it isn't just red, it's red and blue. If you think you can compensate a red cast with the magenta filter, you'll end up wasting a lot of test strips. You will learn (or already know) that the complementary color of magenta is green, so you use the magenta filter for increasing and decreasing red+blue versus green in your final image. Same thing applies to the yellow filter. Yellow is the additive mix of red and green, the complementary color is blue. Use yellow to increase and/or decrease red+green versus blue.
If your color balance is indeed off (and it will be, trust me), take your time and look very carefully which color needs increase or decrease, and think carefully which color filter achieves the desired change.
Conclusions
If you have done lots of dark room printing and possibly also some RA4 and used print drums for these processes, Ilfochrome should be a piece of cake for you, at least on amateur level. After my first successful experiments I have a lot of respect for professional Ilfochrome labs which do perfect color matching and contrast masking and whatnot to reproduce every imaginable source material thrown at them. I, however, do not compete in this league, but I have found a way to print Ilfochrome from most of my slides with "good enough for me" color balance. The aim of this article is to encourage others to try this incredible process and maybe share some of their own discoveries.
Since I was unfamiliar with most of the equipment used for Ilfochrome processing, I decided to spend some time with B&W dry runs of the process. This helped me figure out many steps and also taught me how to do these steps in total darkness. I cut B&W paper to size, placed it under the enlarger, enlarged random negatives or slides on the strip and placed it into the print drum, then ran it through the regular B&W process.
I practiced running the process in a fully repeatable fashion, every step at a controlled temperature for an exact time frame. How long does it take to change from one bath to the next with this drum processor? How long does it take the processor to reach its set temperature? How much chemistry is the bare minimum? Can I do some tasks while the bath is active which could save time later in the process? How to I prepare exposure series in total darkness? Where do I place items so I can find them when I need them in the dark?
Some folks may be natural talents, others may already be experienced from RA4 printing. I am neither so I spent an evening in the dark room performing these dry runs until I was confident I could to all these steps reliably with Ilfochrome sheets. Fortunately all the hazardous steps can be done in day light, especially those steps involving the (nasty&smelly) Ilfochrome chemistry.
Exposure Settings
Since batches of Ilfochrome sheets have slightly varying color balance, a label on the box/envelope gives printers initial filter setting to start with. Once you switch from one batch to the next, and if you keep the rest of the process constant, you can guestimate the new filter values by subtracting the filter values printed on both batches and adding the difference to your last actual filter settings (which may be quite different from the values printed on the box).
With this information we can dial in initial filter settings, but we still don't know about exposure. Not only that I did not find anything useful online, the bigger problem is that different slides may differ in mid tone density by quite a bit, sometimes because of less than perfect film exposure, other times because different slide films have different contrast. So every time I switched slides I took a measurement with my density meter (since you only need to know the difference in densities, a simple light meter could probably be used here if you don't have a density meter for your enlarger).
Since Ilfochrome CLM.1K paper has a contrast of about 1, any difference in paper exposure will be faithfully reproduced by the paper. This allowed me to accurately nail Ilfochrome exposure reliably for very different slides with the density meter. I may have been hysterical about this, but I have read multiple reports about nasty reciprocity failure of Ilfochrome paper. In order to avoid running into this issue even after changing sheet format, I tried to cover most of the calculated exposure difference with the lens aperture and changed exposure time only to cover the small remaining difference.
Anyway, there is no substitute for an exposure series. Since we can run several test strips per dev run with little extra cost, it might well pay off to run fine grained exposure series, chances are high we nail exposure right after the first test run. So there we have it: we know optimal exposure from the test run and once the test strip has been fully washed and dried, we can see whether we need to correct color balance. This is most likely the case since color balance depends on process parameters and chances are the paper maker ran with different parameters than what you will use.
Color Balance
After establishing correct exposure settings I went on to achieve correct color balance. The most difficult aspect of this is that it takes so long to find out how the color balance came out. Remember, you need to let the paper dry completely before you start judging its colors. Since we want to do the absolute minimum number of test runs, I recommend you expose several sections of your test strip with different filter settings, starting with the filter settings printed on the box of the paper stash. If necessary, make multiple test strips, as long as you can fit them in the same drum.
Be sure you know what the filter settings on your color enlarger head really do. Magenta looks a lot like red to my eye, but it isn't just red, it's red and blue. If you think you can compensate a red cast with the magenta filter, you'll end up wasting a lot of test strips. You will learn (or already know) that the complementary color of magenta is green, so you use the magenta filter for increasing and decreasing red+blue versus green in your final image. Same thing applies to the yellow filter. Yellow is the additive mix of red and green, the complementary color is blue. Use yellow to increase and/or decrease red+green versus blue.
If your color balance is indeed off (and it will be, trust me), take your time and look very carefully which color needs increase or decrease, and think carefully which color filter achieves the desired change.
Conclusions
If you have done lots of dark room printing and possibly also some RA4 and used print drums for these processes, Ilfochrome should be a piece of cake for you, at least on amateur level. After my first successful experiments I have a lot of respect for professional Ilfochrome labs which do perfect color matching and contrast masking and whatnot to reproduce every imaginable source material thrown at them. I, however, do not compete in this league, but I have found a way to print Ilfochrome from most of my slides with "good enough for me" color balance. The aim of this article is to encourage others to try this incredible process and maybe share some of their own discoveries.
By all means, go for it! It took me several months of pondering and thinking about little issues, but once I got these all worked out (as described in my article) the process was very straight forward. I will post images in the color forum soon. Good luck with your experiments!
In the technical gallery I have posted three sample images made during my first test runs. The images can be found (there was a url link here which no longer exists), (there was a url link here which no longer exists), and (there was a url link here which no longer exists).
I printed a fair amount of Ilfochrome back in the 90s, but on the then-available RC pearl paper. I always used a hair dryer to dry the test prints for checking color balance. I know of no reason this won't work with the acetate glossy print material. Saves a boat load of time.
thanks for the heads up...
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Hello, I have a Durst 3 bath Roller Processor, and I intend to work with it to make Ilfochrome prints. My questions are this:
- last time I made Ilfochrome it was difficult to wash as I needed to wash them several times before getting the bad smell out of them, how can I avoid this?
- Getting this Ilfochorme prints dry was a trouble. What should I do to get them dry fast and for them to end up really flat?
- I use a gas mask in my darkroom, but this chemicals smell too bad. Is that normal?
- Whitout the water bath that it says I have to give after the second bath, as my Processor has only three baths will I be able to make the prints?
Thank you
- last time I made Ilfochrome it was difficult to wash as I needed to wash them several times before getting the bad smell out of them, how can I avoid this?
- Getting this Ilfochorme prints dry was a trouble. What should I do to get them dry fast and for them to end up really flat?
- I use a gas mask in my darkroom, but this chemicals smell too bad. Is that normal?
- Whitout the water bath that it says I have to give after the second bath, as my Processor has only three baths will I be able to make the prints?
Thank you
With all the cost and time consumption of Ilfochrome process, water and washing are the least of my concerns. I water them like B&W RC prints and did not notice any particular smell, but maybe my nose isn't very sensitive.
I used a paper dryer normally used for B&W RC paper and it worked well. Paper came out flat but needed a little bit of post drying after leaving the paper dryer.
I use a rotating tank processor so the chemistry is always contained somewhere, this may make a huge difference.
I have no experience with leaving out individual steps but would suggest following the recipes to the letter. Is there a chance you can do the fixing step outside of your processor? The fixing step appears to be the least critical step in the Ilfochrome process chain.
Given all your experiences with bad smell and wearing a gas mask, a tank processor could be a better choice for you.
IMPORTANT NOTE: Supposedly, Ilford has announced the imminent discontinuation of Ilfochrome paper, so all those of you who would like to try the process, now is the time to do it or forget it. As I wrote in (there was a url link here which no longer exists):
Here's what I plan on doing:
- Paper can be stored in the freezer for many years according to what I have found in relevant forum postings. So I will stock what I plan on using over the next few years so I can continue to print my favorite slides.
- Chemistry is more short lived according to these same postings but should last for 1-2 years, at least after heavy color corrections.
- Chemistry will be either available after that or I will look into home brewing. There are a few threads here on APUG which describe recipes and refer to further info: (there was a url link here which no longer exists) and (there was a url link here which no longer exists).
EDIT: Oops, I see the last poster beat me to the link.
Apparently it's discontinued. I thought they had government contracts for a few more years but apparently not.
Utter and total bummer, even worse than the end of Kodachrome. I liked Kodachrome but E6 materials are very good. Too bad there's now no really good way to print them. (Yes you can scan and output as inkjet. I said no "really good" way.)
And EDIT II: Internegatives! Why didn't I remember internegatives! I know PE and others have mentioned making pretty good ones on Portra 160. Given the price of Ilfochrome that may prove to be cheaper if not as easy and still give pretty good results. So maybe there is hope for printing those Kodachrome slides I shot, and all the E6 I've shot since then, in a conventional darkroom (without reversal processing RA4 - PE mentioned displaying a print from that, but others have said it's not great, particularly with Fuji which ironically is the paper readily available) after all.
Apparently it's discontinued. I thought they had government contracts for a few more years but apparently not.
Utter and total bummer, even worse than the end of Kodachrome. I liked Kodachrome but E6 materials are very good. Too bad there's now no really good way to print them. (Yes you can scan and output as inkjet. I said no "really good" way.)
And EDIT II: Internegatives! Why didn't I remember internegatives! I know PE and others have mentioned making pretty good ones on Portra 160. Given the price of Ilfochrome that may prove to be cheaper if not as easy and still give pretty good results. So maybe there is hope for printing those Kodachrome slides I shot, and all the E6 I've shot since then, in a conventional darkroom (without reversal processing RA4 - PE mentioned displaying a print from that, but others have said it's not great, particularly with Fuji which ironically is the paper readily available) after all.
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I have chosen to go the interneg route. I have enough different chemistry processes going, between b&w, c-41, ra-4 and E-6 botles filling shelves above the sink.
I do have an almost full 100 sheet 8x10 box of early 90's Kodak Radiance paper that was gifted to me in the last year. I intend to turn to it when I find more time to print precious slide images.
It was designed to use process R-3, which at first I knew nothing about. I figured it needed to work like e-6. I have mixed a first developer that PE graciously helped to work out, to allow me to reversal process this in a tray in the dark after exposure, rinse it, optically flash it, and then feed it as though a normal ra-4 print into my roller processor. The up side at the start with this off board tray work is that you can tell from the low contrast black and white revesed image on the print at optical reexposure if you got the exposure right, before sending a dud futher along for more steps.
Ron has advised me on how to reversal rocess regular ra-4 paper, but it has not worked out well for me in experiments to date. On the other hand, the first run of the Radiance paper with the box recommened filtration virtually matched the Macbeth test image I printed on it the first time I exposed it.
I have also been buying up interneg and dupe film 35mm bulk 100ft loads for $5 a can at old camera shows.
Most of it is quite slow, and hence has not shifted out of workable spec with the right filtration. I calibrate it's parameters in a Bowens Illumitran slide dupe or a Polaroid bench type 4x5 or 35mm copy camera. The e-6 dupe film I plan to use to improve the exposure and contrast of slides that will otherwise need contrast reduction masks.
Contrast reduction masks I have made in the past, and it is a toss up between pre/post flashing the dupe slide or making the contrast reduction or unsharp mask.
As to working with small quantities of expensive colour chemistry in print tubes, I have found in the past that if you need 40mL of fresh solution per print, then save up the solution for the first few prints. What you really need is likely 120mL of wet solution, with at least 40mL of fresh solution as a part of that mix.
I would store the intermediate solution in labelled plastic mugs that would hang with thier bottoms in the water tempering bath that the bottles also used, so that they would be at temp and ready to be replenished and poured back into the tube to help the new solution spread evenly over the whole print surface.
I do have an almost full 100 sheet 8x10 box of early 90's Kodak Radiance paper that was gifted to me in the last year. I intend to turn to it when I find more time to print precious slide images.
It was designed to use process R-3, which at first I knew nothing about. I figured it needed to work like e-6. I have mixed a first developer that PE graciously helped to work out, to allow me to reversal process this in a tray in the dark after exposure, rinse it, optically flash it, and then feed it as though a normal ra-4 print into my roller processor. The up side at the start with this off board tray work is that you can tell from the low contrast black and white revesed image on the print at optical reexposure if you got the exposure right, before sending a dud futher along for more steps.
Ron has advised me on how to reversal rocess regular ra-4 paper, but it has not worked out well for me in experiments to date. On the other hand, the first run of the Radiance paper with the box recommened filtration virtually matched the Macbeth test image I printed on it the first time I exposed it.
I have also been buying up interneg and dupe film 35mm bulk 100ft loads for $5 a can at old camera shows.
Most of it is quite slow, and hence has not shifted out of workable spec with the right filtration. I calibrate it's parameters in a Bowens Illumitran slide dupe or a Polaroid bench type 4x5 or 35mm copy camera. The e-6 dupe film I plan to use to improve the exposure and contrast of slides that will otherwise need contrast reduction masks.
Contrast reduction masks I have made in the past, and it is a toss up between pre/post flashing the dupe slide or making the contrast reduction or unsharp mask.
As to working with small quantities of expensive colour chemistry in print tubes, I have found in the past that if you need 40mL of fresh solution per print, then save up the solution for the first few prints. What you really need is likely 120mL of wet solution, with at least 40mL of fresh solution as a part of that mix.
I would store the intermediate solution in labelled plastic mugs that would hang with thier bottoms in the water tempering bath that the bottles also used, so that they would be at temp and ready to be replenished and poured back into the tube to help the new solution spread evenly over the whole print surface.
Roger & Mike,
yes, I am aware of inter negatives and RA4 as alternative to Ilfochrome, and it is most certainly something I should look at when I finally run out of Ilfochrome materials. The challenge I see with this is finding a negative film which doesn't have too much character of its own. I'm especially concerned about the color palette of Portra and Ektar, and Fuji will most likely quit C41 long before they quit E6.
yes, I am aware of inter negatives and RA4 as alternative to Ilfochrome, and it is most certainly something I should look at when I finally run out of Ilfochrome materials. The challenge I see with this is finding a negative film which doesn't have too much character of its own. I'm especially concerned about the color palette of Portra and Ektar, and Fuji will most likely quit C41 long before they quit E6.
Porta should work and I think Kodak recommends Portra 160 as a replacement for interneg film. I'd think Ektar would be too contrasty even aside from contrast issues.
I would love to do some more Ilfochrome if a) it weren't so expensive and b) I thought I would be able to get it for several years going forward. Sigh.
I would love to do some more Ilfochrome if a) it weren't so expensive and b) I thought I would be able to get it for several years going forward. Sigh.
Rudeofus, You seem to have lots of Ilfochrome knowledge, so I will post here...
I am getting back into darkroom photography after nearly 30 years out of it (I now have teenage daughters who are interested in photogtaphy and I want them to know more than cell-phone snaps uploaded to facebook). I'm rather apalled and saddened at the state of the suppliers whom I used to rely on for so much in the way of papers, chemistry, and process machinery. Still, I'm perusing eBay daily as I remember one item, technique or other, and that's how my old Cibachrome experience got me here (I started with the old "Discovery Kit" with 20 sheets of 4x5 and the P12. (???) process)
Well, in addition to buying a 5L P3 (or is it P30?) chemistry kit and a bunch of paper, I bought a big roll of 35mm Micrographic film. I know it says it is extremely slow at ASA/ISO=1. I can manage that.
What I need to find out is how to process it. It says to use P5 chemistry. I have inquired at every place I could find on the Internet (Including Ilford Imaging) who had any content whatsoever about selling the film as to the availability of the P5 chemistry, to no avail.
Can I run the Micrographic CMM.F4 in P3 or P30 chemistry if I cannot get P5?
Thanks in advance for any help...I'm new to the forums here, and while I have quite a bit of darkroom experience, it's pretty stale and things have changed a lot since the 1980s, so be gentle on me, my friends...
I am getting back into darkroom photography after nearly 30 years out of it (I now have teenage daughters who are interested in photogtaphy and I want them to know more than cell-phone snaps uploaded to facebook). I'm rather apalled and saddened at the state of the suppliers whom I used to rely on for so much in the way of papers, chemistry, and process machinery. Still, I'm perusing eBay daily as I remember one item, technique or other, and that's how my old Cibachrome experience got me here (I started with the old "Discovery Kit" with 20 sheets of 4x5 and the P12. (???) process)
Well, in addition to buying a 5L P3 (or is it P30?) chemistry kit and a bunch of paper, I bought a big roll of 35mm Micrographic film. I know it says it is extremely slow at ASA/ISO=1. I can manage that.
What I need to find out is how to process it. It says to use P5 chemistry. I have inquired at every place I could find on the Internet (Including Ilford Imaging) who had any content whatsoever about selling the film as to the availability of the P5 chemistry, to no avail.
Can I run the Micrographic CMM.F4 in P3 or P30 chemistry if I cannot get P5?
Thanks in advance for any help...I'm new to the forums here, and while I have quite a bit of darkroom experience, it's pretty stale and things have changed a lot since the 1980s, so be gentle on me, my friends...
As Roger said "if you could get it going forward."
Unfortunately you can't find it because it's gone. Out of production. Living in the land of Kodachrome.
And it breaks my heart. Kodachrome/Ilfochrome was part of what drew me back to the darkroom after the kid was raised.
I'm just praying I don't have to raise my own chickens to make albumen prints one day.
Unfortunately you can't find it because it's gone. Out of production. Living in the land of Kodachrome.
And it breaks my heart. Kodachrome/Ilfochrome was part of what drew me back to the darkroom after the kid was raised.
I'm just praying I don't have to raise my own chickens to make albumen prints one day.
Yes, technically Ilfochrome is dead, its manufacturer announced its discontinuance and stated that after one final batch run in 2013 it will be over and done with. I have in the mean time stacked up on paper and will order more chemistry in 2013, which will hopefully keep me going until I learn to home brew it.
The big problem with Kodachrome was its complex development process, and when Dwayne's announced its final run that was it. Ilfochrome on the other side is quite easy to home process, so as long as frozen paper stays useful one can do Ilfochrome. If Steven Frizza made K14 work in his lab, I will go and home brew Ilfochrome bleach in my kitchen once I run out of kit chems.
To tintruder: sorry, I have no knowledge about P5 or microfilm. The Ilford website mentions it here, so I would guess some Ilford retailer in your country would be able to supply you with the chemistry. Looking at the description of the P5 chems, they look very similar to P3, in the worst case you could get some "interesting" colors ...
The big problem with Kodachrome was its complex development process, and when Dwayne's announced its final run that was it. Ilfochrome on the other side is quite easy to home process, so as long as frozen paper stays useful one can do Ilfochrome. If Steven Frizza made K14 work in his lab, I will go and home brew Ilfochrome bleach in my kitchen once I run out of kit chems.
To tintruder: sorry, I have no knowledge about P5 or microfilm. The Ilford website mentions it here, so I would guess some Ilford retailer in your country would be able to supply you with the chemistry. Looking at the description of the P5 chems, they look very similar to P3, in the worst case you could get some "interesting" colors ...
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Hello, I have a Durst 3 bath Roller Processor, and I intend to work with it to make Ilfochrome prints. My questions are this:
- last time I made Ilfochrome it was difficult to wash as I needed to wash them several times before getting the bad smell out of them, how can I avoid this?
- Getting this Ilfochorme prints dry was a trouble. What should I do to get them dry fast and for them to end up really flat?
- I use a gas mask in my darkroom, but this chemicals smell too bad. Is that normal?
- Whitout the water bath that it says I have to give after the second bath, as my Processor has only three baths will I be able to make the prints?
Thank you
A great solution to drying problems with ilfochrome that pro labs use is the addition of Epsom salts (magensium sulphate) in the final wash, this heavy water causes the surface of the print to dry with a better gloss.
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As the owner of one of the last Ilfochrome labs on earth I can confirm that Ilfochrome is a far simpler process than Kodachrome and it would be very viable and easy to make the chemistry from scratch. Ilfochrome as long as the chemistry is kept in stringent control is a very very very simple process.
The huge hurdle for it will be getting fresh material to expose....
And, I might add, that the coatings are far far simpler than Kodachrome! We handcoated Ilfochrome in our lab at EK, at least a serviceable example. If we had continued it would have been fully functional as we hit it pretty much right on, first try.
PE
PE
Wow, hand coating Ilfochrome .... can you give us any indication whether the chemistry involved in this is obtainable by random home brewers? Is this something we could remotely consider doing once we run out of materials?
I have given the entire process sequence elsewhere here. Right now, I am tied up with a workshop and cannot dig out the information. Sorry. I cannot even find the original single layer strips that I made to show feasibility. One was damaged and I had planned to make another set.
PE
PE
I've spent some time searching for Ilfochrome recipes on APUG and here is what I found so far:
A long list of odd ball (to me) chemistry is mentioned but some are obtainable from Sigma Aldrich: 2,3-Dimethylquinoxaline, 2-hydroxy-3,6,7-trimethylquinoxaline, Sodium 3-nitrobenzenesulfonate, Phenazine, Quinoline and N,N-Dimethyl-4-nitrosoaniline.
- I found (there was a url link here which no longer exists) where a lot of chemistry is thrown around. Unfortunately brookse never posted a specific recipe, but he seems to have one.
- (there was a url link here which no longer exists) is a thread with some more info and a recipe which is said to work poorly.
- (there was a url link here which no longer exists) is another thread with a recipe. And (there was a url link here which no longer exists). And (there was a url link here which no longer exists).
- A number of threads recommend Dr. Beers developer to replace the Ilfochrome dev. (there was a url link here which no longer exists) is the recipe.
- Following the advice in these threads I searched for "dye bleach ciba patent" and boom, a long list of patents (like this one and that one from EK) describing dye bleaches and referencing other patents on that topic.
A long list of odd ball (to me) chemistry is mentioned but some are obtainable from Sigma Aldrich: 2,3-Dimethylquinoxaline, 2-hydroxy-3,6,7-trimethylquinoxaline, Sodium 3-nitrobenzenesulfonate, Phenazine, Quinoline and N,N-Dimethyl-4-nitrosoaniline.
All of the exotic catalysts will work. The 2, 3 Dimethyl quinoxaline is what Ilford uses AFAIK. I am intending to design my color material (If I ever go it) around Phenazine probably. IDK.
All of the above are rather toxic and should be handled carefully and all DB bleaches are similar. They are about pH 1 or so, have HCl or H2SO4 in them, Thiourea, NH4Br, and other things. Recent DB bleaches use Sulfamic Acid with the same low pH.
You must used a support such as YUPO or RC, as the bleach destroys most papers.
PE
All of the above are rather toxic and should be handled carefully and all DB bleaches are similar. They are about pH 1 or so, have HCl or H2SO4 in them, Thiourea, NH4Br, and other things. Recent DB bleaches use Sulfamic Acid with the same low pH.
You must used a support such as YUPO or RC, as the bleach destroys most papers.
PE
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