PDA

View Full Version : Dryplate ferrotypes



Pages : [1] 2

kevin klein
01-08-2007, 11:25 AM
Many people have wondere about dry ferrotypes other than Rockland kits, the only secret ingredient is the addition of .5 gm Ammoniumthiocyonate to each ounce of Dektol developer at a 1:1 working strength, develop 2 min.

Exposure test for me was F:32, 8 sec, sunny day.

TheFlyingCamera
01-08-2007, 02:21 PM
I'd be interested in this if you had some more information. This is painfully vague. Would you care to be more forthcoming with details about what you mean?

joshverd
01-08-2007, 05:06 PM
Very interesting, I have not heard this before. What emulsion did you use?

Jim Noel
01-08-2007, 05:33 PM
I'd be interested in this if you had some more information. This is painfully vague. Would you care to be more forthcoming with details about what you mean?

By all means, fill us in. This is just enough info to make the mouth water.

Jim:confused:

kevin klein
01-09-2007, 12:21 PM
The emulsion used was Rockland AG plus and one I made ny self from the Kodak AJ-12 instructions. The home made emulsion seemed to work a little better. The exposures : F:32, 8 sec, sun.

I first used Dektol developer diluted 1:2, Then 1:1 and got a better image. The next time the development will be done with undiluted developer along with the thiocyanate.

The plates used where jappaned iron plated for the collodion process, but some times the emulsion peeled of when drying and some times it stayed put.

I gave the last plates a coat of urithane spray and that caused a chemical fog on the jappaned plates and the black trophy aluminum plates as well.
I have albumen subbed some black aluminum plates this morning and will put them to the test. The backs of the plates had also been varnished to prevent chemical reactions with the developer.

I will let you know how things turn out.

Photo Engineer
01-09-2007, 12:51 PM
With these rather primitive emulsions, it is possible that you might get dichroic fog.

PE

kevin klein
01-10-2007, 12:13 PM
The tests today have given very unexpected results, it seems that the speed of the plates has risen dramaticaly scince the last time.

The emulsion used was AG Plus with no additives, plates used are jappaned iron, and trophy aluminum with poly urithane coating. The first time I used a plate with urithane they came out fogged, but I think that was due to a different emulsion beeing used. This time I only made 4 plates so as not to waste material incase of chemical problems. The first plate was exposed at the same speed as the first trials, about .7,(f:11, 6 sc, overcast) the plate was extreamly fogged over and thaught...oh crap! But looking more carefully I noticed the corners where the plate was blocked from light had no fogging at all. This lead me to to the hopefull thaught that maybe, just maybe, the thing could have been over exposed, three more tries followed, each one with less and less exposure. By the time I got to the last plate the exposure was reduced to F:16, 1-1.5 sec. This translated to a speed of about .12, and still a bit over exposed and clear shadow areas.

The first exposures last week had been made at f:32, 8 sc. now its way faster. I dont know what is happening but it is good. More testing is needed, maybe the urithane on the two plates and the aspaltum japan on the other two had a sensitising effect when heated during coating and released sulphur ions(just a thaught). the emulsion had not been remelted over and over, it was transferred to a diferent container so small portions can be taken out and melted.

Things are getting interestinger and interestinger.

kevin klein
01-10-2007, 12:18 PM
The tests today have given very unexpected results, it seems that the speed of the plates has risen dramaticaly scince the last time.

The emulsion used was AG Plus with no additives, plates used are jappaned iron, and trophy aluminum with poly urithane coating. The first time I used a plate with urithane they came out fogged, but I think that was due to a different emulsion beeing used. This time I only made 4 plates so as not to waste material incase of chemical problems. The first plate was exposed at the same speed as the first trials, about .7,(f:11, 6 sc, overcast) the plate was extreamly fogged over and thaught...oh crap! But looking more carefully I noticed the corners where the plate was blocked from light had no fogging at all. This lead me to to the hopefull thaught that maybe, just maybe, the thing could have been over exposed, three more tries followed, each one with less and less exposure. By the time I got to the last plate the exposure was reduced to F:16, 1-1.5 sec. This translated to a speed of about .12, and still a bit over exposed and clear shadow areas.

The first exposures last week had been made at f:32, 8 sc. now its way faster. I dont know what is happening but it is good. More testing is needed, maybe the urithane on the two plates and the aspaltum japan on the other two had a sensitising effect when heated during coating and released sulphur ions(just a thaught). the emulsion had not been remelted over and over, it was transferred to a diferent container so small portions can be taken out and melted.

Things are getting interestinger and interestinger.

Correction, the speed should be 12 not .12

Photo Engineer
01-10-2007, 01:09 PM
It is possible that the plates are gaining speed due to sulfur in the formula or due to reduction sensitization from any reducing agent in the formula.

This can happen if the formula contains no stabilizer. It depends and not knowing the formula makes diagnosis difficult. Using those japanned aluminum plates does not help. Generally, aluminum is not good with photo products such as emulsions. Some lacquers contain harmful chemicals as well.

Try it on a plain glass plate and see what happens.

PE

kevin klein
01-10-2007, 03:12 PM
The aluminum plates are black coated trophy engraving plates with a varnish coated on the back to prevent reactions. Also they have been coated on the working surface with a brush on urithane varnish to give the gelatin something to hold on to or it will peel right off when drying. Sometimes the drying emulsion will pull the japan from the plate.
Spray urithane is also being tested again.

Two of the plates done today have shown some unexpeted results. The first two are over exposed but the other two that looked over exposed actualy toned down during drying and one is under exposed while the other is fairly good. This might have happened because they did not get washed other than a quick rinse and put aside for reclaiming. Upon seeing the change in image I speculate that there was still fixer remaining in the surface and cleared the shadow areas and gave them a better wash, but it is still better to get a good image right off with out having to guess.

Eight more 1/6th plates have been coated for tomorrows run, will let you know.

kevin klein
01-11-2007, 04:35 PM
After repeating the prosedures several times here is what I have come up with using Rockland AG Plus emulsion coated on black aluminum trophy plate, coated with spray or brush on poly urithane varnish. Coat the back too so the aluminum will not screw up the chemicals.


Developer, Dektol diluted 1:1, plus 1gm Ammonium Thiocyanate to 3 oz. of working developer.

Exposure for tins,in my experiments have been f:45, 6 sec. overcast. This means a speed of about 12. for ambrotypes use only half exposure.

Develop 90-120 sec. It is a good idea to put a cover over the developing tray to keep the ammonia fumes from beeing a bother. rinse in water a few secons,( some say to go directly to fix ), Then fix about 10 min. in hypo.

Wash 10-15 min. then let dry. The image will darken a little when drying.

The images have all shown a little fog in the shadoe areas but it is'nt too bad. The addition of 1.5 gm Ammonium Thiocyanate to 3 oz. of developer will give a little brighter image but will also increase the fog a little more.

Give it a try.

joshverd
01-11-2007, 09:57 PM
Great information. I'd love to see some of your results. I will be trying this for myself as soon as my thiocyanate comes in. I really like the idea of not being dependent on the not-so-dependable rockland developer.

PhotoEngineer, I would like to hear a little more on reduction sensitization. Any reducing agent that doesn't destroy the emulsion will do it? What are some common reducing agents used for this purpose? Also, how could we reduce fog on these plates?

Thanks for the info,
Josh

Photo Engineer
01-11-2007, 10:19 PM
Josh, I never played around with "R" typing or reduction sensitization. I may have some literature on it. If I do, I'll see what I can post. None of my projects used it.

Fog reduction in these plates may be coming from an amine in the subbing layer, or it may be inherent in the emulsion. Try adding some methyl benzotriazole to the emulsion. Since I don't know grain size or concentration, this would have to be done by trial and error. Make up a 1% solution in methyl alcohol and add it a drop at a time and coat one plate after each drop is mixed in well. This should give a starting point.

PE

Photo Engineer
01-12-2007, 10:27 AM
The only information I could find is a suggestion to use Stannous Chloride for reduction sensitization. IIRC, it is rather rapid acting and prone to fog.

Stannous Chloride is such a strong fogging agent that it is used as the current reversing or fogging agent in the E6 process, so exercise due caution using it in the darkroom.

I have no information on suggested amount to use, but since it is a surface effect just like Sulfur or Sulfur + gold sensitization, the quantity is dependant on surface area.

PE

kevin klein
01-12-2007, 10:41 AM
I know the fog is not from the plate because the ambro version also had some fog, but keep in mind that this is just experimental and someone out there might take this thing and run with it and find improvements.

The only existing plate I kept for comparison reasons was a little more brighter than the Rockland coated plates. I used my own emulsion on that one and am going to see if the effect is reproducable, although the speed was a lot slower, about .7 to 1.5 where as the the speed of the actual rockland tintype kit is about 1.5.

Photo Engineer
01-13-2007, 10:36 AM
Josh;

More info on "R" typing.

It appears that it is not used in any common product today AFAIK. The current products use Sulfur, Selenium and Tellurium as well as these in combination with Gold salts.

Early products which used formaldehyde for hardening often became foggy due to formalin causing reduction sensitization. Formalin can be used to give very high (2 electron type) sensitization, but is not easily controlled as it tends to react with gelatin and is also a gas. This latter method was described in work done in France and was later taken up by Agfa but never commercialized, IIRC.

Formalin was present in old style coatings as hardner and gradually fogged the emulsions. The formalin either did not react fully with the gelain, or the reaction reversed. Formalin also continued to harden coatings well after they were released for sale. This slow 'afterhardening' is described by both Haist and Mees and James in their texts. It shows that formalin was present for quite some time as formaldehyde in some form or another.

I believe that this further illustrates the easy fog formation when trying to use "R" typing in photo products and is probably why it is not widely used.

PE

joshverd
01-13-2007, 11:41 AM
Very good information, thanks for all of it. Once again I am not dissapointed!

sdivot
12-11-2008, 11:52 PM
This is kind of an old thread, but I'll try to revive it!
Basically, I'm trying to make the modern tintypes. I use the Rockland developer kit and it works fine. But I want to try one of the Dektol variations that doesn't require I buy the expensive Rockland kit.

First recipe I tried:
32 ounces Dektol stock
66 ounces water
2 ounces exhausted paper fix (this is working strength paper fix, right?)
Result: No reversal. Plate went black in the fix (emulsion went clear).
I monkeyed around with the amounts and never got satisfaction.
I've seen this recipe in two books, so it works for someone. Maybe a different paper fix would work?

Second recipe:
This is the one I got from this thread.
Dektol 1:1
1 gram of Ammonium Thiocyanate for every 3 ounces of Dektol.
Result: The image reversed like it should, but my blacks are not black at all. I'm printing a digitally generated 21 step wedge using an enlarger and contact printing. I'm not getting nearly enough density in my blacks. No matter my exposure times, the blacks are way too weak.
I later tried various different amounts of Am. Thio. with no help.
I made the concentration of Dektol higher, but it didn't reverse and went black in the fix.

I'm not a chemist obviously. I'm at a point where I'm just guessing, trying new things. Pretty silly. Can anyone give me some ideas/advice/direction?
Thanks,
Steve
www.scdowellphoto.com

kevin klein
04-07-2009, 11:58 AM
Steve
I have had the same problems with my on plates not having enugh density in the black areas. Some of them did come out perfect though and tried to reproduce the effect but had no succes. I think the slightly fogged shadow areas are about as good as they are going to get. My next plan was to try Rockland emusion to see if that made any diference.

Like you I tested varying amounts of this and that but had no better results. I am wondering if Rockland uses something else in there developer additive.

PHOTOTONE
05-01-2009, 06:55 PM
I'm a "bit" confused here. Are we talking about true Reversal images, or the traditional Tintype (style) where the developed emulsion is lighter than the japanned metal plate it is coated on, thus resulting in a Positive looking image?