The sodium pyrosulphite and sodium metabisulphite is the same compound with formula Na2S2O5.
http://en.wikipedia.org/wiki/Sodium_metabisulfite
Holos from yesterday
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info.crew
Holos from yesterday
Ok, I will try that tips. Thanks. It will consume qite long time to tune the process to optimum.
The sodium pyrosulphite and sodium metabisulphite is the same compound with formula Na2S2O5.
http://en.wikipedia.org/wiki/Sodium_metabisulfite
The sodium pyrosulphite and sodium metabisulphite is the same compound with formula Na2S2O5.
http://en.wikipedia.org/wiki/Sodium_metabisulfite
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JohnFP
Holos from yesterday
Info, you mentioned you may be getting different gelatin. Is that something you are going to do? It may elliminate most of your problems and you can keep everything your doing about that same.
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info.crew
Holos from yesterday
Yes, I plan to obtain the original photographic gelatine p.a. grade for lab use from our local chemical store. It cost just about 30 USD for kilogram. I hope, that has much more better properties than cooking gelatine, what I use. I buy the cooking one by the 20g bags and it has probably different properties in every batch.
I plan to use the two baths - one for fixer, one for reducer, maybe obtain the kodak solution, four baths to get more narrowband pictures and do some more work to improve my home lab - obtain large new first surface mirror, original pinhole for my 45x objective (I use the pinhole made from electric shaver covering planchete - 40um hole, slightly hexagonal, not qite round)
I found, that the Kodak solution is available as two solutions - fixer and hardener solo. It is necessary to use both? (for reducing Cr)
I plan to use the two baths - one for fixer, one for reducer, maybe obtain the kodak solution, four baths to get more narrowband pictures and do some more work to improve my home lab - obtain large new first surface mirror, original pinhole for my 45x objective (I use the pinhole made from electric shaver covering planchete - 40um hole, slightly hexagonal, not qite round)
I found, that the Kodak solution is available as two solutions - fixer and hardener solo. It is necessary to use both? (for reducing Cr)
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info.crew
Holos from yesterday
P.S. My name is Pavel or Pablo. Info is just a unoficial crazy nickname
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JohnFP
Holos from yesterday
Ok Pablo, got it.
Well the two part Kodak Rapid fixer usually come with both Part A and Part B.It will contain everything you need, reducer and hardener in the correct ratio if you mix it 7:1 as directed for paper. Here is what I have used. http://www.calumetphoto.com/item/KP02020/ If you click on the image you will see the large bottle has two descriptions. One to make a gallon and one to make two gallons. Use the formula to make two gallons which turns out to be 7:1 because the large bottle is about a quart (1/4 gallon). I tell you 7:1 because your measuring cups, as with most scientific measurers are in ml. So as long as you use 7:1 you will be fine. I use 700ml water, 100ml part A and 10ml part B. This is easy to do, enough liquid for most trays and fits nicely back into a 1 liter bottle for storage.
I am kind of sad you decided to try the Kodak Fixer because you are doing amazing trials on simply using Sodium Metabisulfite and Alum. When I get back into the lab, it is what I plan to use.
I think your biggest help will be the gelatin switch. While Knox Unflavored cullinary gelatin works great here in the states I am not sure of the bloom strength of your cullinary gelatin. Do you know the bloom of the photo grade gelatin? Can you call the manufacturer of your cullinary gelatin and ask them what bloom their gelatin is? It would be nice to know both so that you can actually note the difference after trying both.
A side note, usually food grade gelatins are more consistant then non food grade gelatin. Are you sure you see a difference from batch to batch. I think it is designed to have low bloom to start with. Probably giving the foods you make with it able to carry more water and thus more moist.
Well the two part Kodak Rapid fixer usually come with both Part A and Part B.It will contain everything you need, reducer and hardener in the correct ratio if you mix it 7:1 as directed for paper. Here is what I have used. http://www.calumetphoto.com/item/KP02020/ If you click on the image you will see the large bottle has two descriptions. One to make a gallon and one to make two gallons. Use the formula to make two gallons which turns out to be 7:1 because the large bottle is about a quart (1/4 gallon). I tell you 7:1 because your measuring cups, as with most scientific measurers are in ml. So as long as you use 7:1 you will be fine. I use 700ml water, 100ml part A and 10ml part B. This is easy to do, enough liquid for most trays and fits nicely back into a 1 liter bottle for storage.
I am kind of sad you decided to try the Kodak Fixer because you are doing amazing trials on simply using Sodium Metabisulfite and Alum. When I get back into the lab, it is what I plan to use.
I think your biggest help will be the gelatin switch. While Knox Unflavored cullinary gelatin works great here in the states I am not sure of the bloom strength of your cullinary gelatin. Do you know the bloom of the photo grade gelatin? Can you call the manufacturer of your cullinary gelatin and ask them what bloom their gelatin is? It would be nice to know both so that you can actually note the difference after trying both.
A side note, usually food grade gelatins are more consistant then non food grade gelatin. Are you sure you see a difference from batch to batch. I think it is designed to have low bloom to start with. Probably giving the foods you make with it able to carry more water and thus more moist.
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info.crew
Holos from yesterday
I am not sure, what exactly is the "bloom strenth". It is some kind of unit of measurement or some relative nbumber?
I would like to use the pyrosulphate and alum, because it is very cheap and commonly available in drugstore.
The only disadvantage is that the solution smell by the SO2 and surface covers after few plates by the hydrophobic layer - maybe the excess of the rain-X. I also tried the P11 epoxy hardener - diethylenetriamine directly into the gelatine, which make relative quick dark reaction. It has very alkalic properties, so it must be pH adjusted before the gelatine is added, or the gelatine solution does not make the gel, even in the fridge in few days. The plates after 3 days are totaly hardened. Maybe it would be good for silver halide plates.
I would like to use the pyrosulphate and alum, because it is very cheap and commonly available in drugstore.
The only disadvantage is that the solution smell by the SO2 and surface covers after few plates by the hydrophobic layer - maybe the excess of the rain-X. I also tried the P11 epoxy hardener - diethylenetriamine directly into the gelatine, which make relative quick dark reaction. It has very alkalic properties, so it must be pH adjusted before the gelatine is added, or the gelatine solution does not make the gel, even in the fridge in few days. The plates after 3 days are totaly hardened. Maybe it would be good for silver halide plates.
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Danny Bee
Holos from yesterday
it look like you have a good formula and exposer and fixing i can tell just by looking at the corner where the clip was that held the plate. That is always a good test the corner should be a little milky and next to it should be clear.I would not stray to much off what is working for you. there are too many rabbit trails you can get lost in. also it looks like the light covering the plate at exposer is not evenly placed. it is very hard for our eyes to tell levels of light thats where a good light meter comes in. also i see streaks in the one of a copy of a photo if you add a wetting agent to your water it will help alot in the end product.
the best fixer i found to use for dcg is kodak professional rapid fixer it has a hardner and when mix as stock the working bath would be 1 to 7 one part stock to 7 parts water...sometime a new person in dcg can get lost in all the tinkering that many of us do here , and some time its a distraction.
you have done a great job looking foward to seeing more of you work
the best fixer i found to use for dcg is kodak professional rapid fixer it has a hardner and when mix as stock the working bath would be 1 to 7 one part stock to 7 parts water...sometime a new person in dcg can get lost in all the tinkering that many of us do here , and some time its a distraction.
you have done a great job looking foward to seeing more of you work
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Danny Bee
Holos from yesterday
hey john when are you going to continue your testing on this?JohnFP wrote:Ok Pablo, got it.
I am kind of sad you decided to try the Kodak Fixer because you are doing amazing trials on simply using Sodium Metabisulfite and Alum. When I get back into the lab, it is what I plan to use.
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it is better that he stick with Rapid Fixer for a time. till you work out all the bugs and give us the skinny on it
your so good at testing John -
info.crew
Holos from yesterday
Well, during the processing of the plate, where the sanwiched photogtraphy was shot, there were used the clip to hold the sanwich. The area covered with the clip was almost clear - just very little milky. But I have found, that the treatment of mold glass by the rain-x before every batch of plates is not a good way, because the plates are then nonuniformly covered with this hydrophobic stuff and it leaves ugly artifacts on the surface. I tried to add a hosehold surfactant to the bath, but I obtained no significant efect. But also plates didn't worse. Next week I gonna do more experiments, so I will place here a report.it look like you have a good formula and exposer and fixing i can tell just by looking at the corner where the clip was that held the plate. That is always a good test the corner should be a little milky and next to it should be clear.
I also foud, that I can get a relatievly cheap first surface mirror - 50x70 cm for cca 75 USD. I bought a 10mm float glass and I will leave it for vapor depositing by the titanium layer to get 0% transmisivity in the company, which do darkening of the automobile glass. This layer is very durable, much more than Al, but the reflectivity is not such bright.
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JohnFP
Holos from yesterday
Danny, why are you discouraging using safer and simpler to obtain chemicals with the added benifit of being able to control reducing and hardening separate? Do you not understand that SM and ALum are exacly the two chemicals needed and all the other "Stuff" in the rapid fixer is not needed?Danny wrote:hey john when are you going to continue your testing on this?
it is better that he stick with Rapid Fixer for a time. till you work out all the bugs and give us the skinny on it your so good at testing John
I think he is doing great and it is not the fixer but the gelatin that needs attention to.
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Pablo, Bloom is a standard relative measurement and it is basically how hard the gelatin will get over a specific time period. So if you let a low bloom gelatin emulsion set for 24 hours, it may only get as hard as a high bloom gelatin emulion of only 4 hours old.
The reason I ask is this makes a BIG difference. And I would hate to see you buy photo grade gelatin, only to have it get too hard too quick for you. But the good news is, if you have your existing, what I believe to be low bloom gelatin, and you get some photo grade, which I believe will be high bloom gelatin, you can mix the two to get the desired bloom strength. This is why I asked if you could contact the producer of your food grade gelatin and the producer of the photo grade gelatin and find out the blooms of each. I find that a bloom about 210-220 is easiest to work with.
If you tell me the name and brand of the food gelatin you use now and the photographic gelatin you plan to use, I can do some research for you and try to help you find out the blooms of each.