wet plate negative copper intensification
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- เผยแพร่เมื่อ 17 ธ.ค. 2024
- A Wet plate collodion image made over a transparent substratum can be seen as a positive image by reflection or negative by transmission. In order to be used as positive the density must be low. A collodion negative, on the contrary, needs high densities to be effectively printed, especially through old photographic techniques, like salted paper or albumen print. This is why a process of intensification must be performed after development. The two main process are iodine and copper intensification. Iodine is a bit tricky, but allows a better control of the result. Copper procedure is easier and quick, and in old times has been for these reason preferred for itinerant collodion. Here a tutorial for this technique.
This video starts where everyone one else stops! wow process. It needs lot of precision and patience to get such results.
thanks for making this great demo! would love to see a demo on the iodine and pyro redevelopment 🤞🤞🤞
Love it! Thank you for the video! I was always doing with redevelopment (iodine), but now I have a project in mind that will take many plates to redevelop and I don't have 30 min for each plate. With bleaching is much easier. Of course as you've mentioned you don't have so much control, but you can adjust the contrast during printing, so perhaps I do not need all the control.
+Borut Peterlin Thanks for the comment. The only problem is that copper intensification is Silver consuming. I need some work and trial to understand how many plates can be treated before it loses its strength. Giorgio
Thank you for this demo!
you're welcome
Always important when you want to show the copper intensification to also include how you collect the sand and bring it to the glass factory to produce your plate.
I stopped using this technique a long time ago because of higher silver prices and also because if the plate is over exposed but still not enough density the intensification will be too much. I now develop the plate as far as it will go and then intensify by using the same developer with a little silver bath added until it looks right then rinse, fix and wash. Or, develop as usual, fix and wash, then use developer and silver to build up density, wash, dry and varnish as usual.
@Giorgio Bordin bravo, bravissimo! Great job! I will be soon trying to shoot plates for the first time! My intention is to print the plates on albumen, maybe Van Dike. So I understood that the appropriate density to print those processes is not achievable straight out of the camera and is better to intensify the negative? Grazie!
Holy density
It wasn't clear in the video or subtitles -- was this bleach and intensify process done while the collodion was still wet, in that fifteen minute or so working time frame, or after the collodion has dried but before varnishing the plate?
the steps are done as they are shown. Bleach is done after washing the fixed plate.
@@giorgiobordin7779 Thanks. I thought so, but wasn't sure.
Fab video. Want to make some ambros with more density so I can try salt contact printing. Is there any alternative to the Nitric Acid?...I can't get it where I live.
I've never tried without or with other acid. Where do you live? You can buy from international sellers, I'm sure someone can ship to you, even at the North Pole.
@@giorgiobordin7779 Hong Kong. They are very strict about chemicals here I guess because of the density of people living in massive towers. It's very challenging just doing tintypes. 😥
@@isuckatguitar6252 oh my... since it uses Silver nitrate, some nitric acid lowers the pH without introducing new chemicals. I think that Choridric acid could be used as well. However I don't think it is easier to find. Acetic acid? Maybe... You should try with little pieces of glass so you need little amount of chemicals and don't waste too much money if it doesn't work; start without nitric acid, so you can just add in a second time. Nitric acid is used also to etch zinc or copper plates for gravures. It could be found in fine art supplies.
@@giorgiobordin7779 Thanks for your input.
@@giorgiobordin7779 you probably don't want to introduce more anons into solution-- I don't think any acid other than nitric will work
Sorry. I ask you a question about the language.
Is it correct to use 60% silver nitrate solution and 6 drops of nitric acid in the last step??
What% purity should nitric acid be used?
That type of intensification was used for line art using various bleaches and silver but also sulfides. It’s a one shot deal and not variable. You should give redevelopment a try. The plate is made sensitive to light by a quick wash in dilute iodine. After washing in water it is exposed to daylight and then you pour pyrogallic acid developer with drops of silver onto the plate. The process takes about ten minutes with repeated applications of the developer but it doesn’t streak like intensification and the build up of density is gradual. You can do a just little as needed or even more than the intensification process.
I know very well that kind of intensification, and is my main method. Check my book for specs if you want.
www.amazon.it/collodio-collodio-positivo-negativo-illustrata/dp/8869272141/ref=sr_1_1?__mk_it_IT=ÅMÅŽÕÑ&crid=HC7Z46POOXY5&keywords=Giorgio+Bordin+fascino+collodio&qid=1664745667&sprefix=giorgio+bordin+fascino+collodio%2Caps%2C88&sr=8-1.
Copper is a valuable alternative, especially when you make negatives in open spaces. Quick and simple.
Woww! (When you wrote the comment on video I say loud this before 1 sec) :-)
Nice resolution, I try this a next weekend! THX!
I have a question: It seems to me the bleach solution using only one times?
The intensify silver nitrate must 60%? Not enough only 10-20%?
Kristian, thanks for your woww. Yes, the bleach I think it is a one shot, but it depends also from the amount of fluid. I use the less I can. The silver nitrate can be re used.
If you want to see the albumen print of this negative, go here:
[www.flickr.com/photos/gbordin/24121252015/in/dateposted/]
If you want more try to download the "Silver Sunbeam" by J. Towler
I used a 30% silver nitrate solution, it is possible
Can this technique be used on silver dry plate????
Silver gelatin dry plates are actually like modern films, the main difference being the support (glass vs polymer) and the composition of "emulsion". There are ways to intensify silver gelatine negatives, and could be similar at a glance because both are two-step processes, but they deeply differ.
With silver gelatine, you bleach the film and then redevelop. However, the first step whitens the image but is not a bleach. You confer Bromide to the image and then add silver nitrate. The new formed silver bromide precipitates and makes the image stronger, adding new silver. You work with a film of collodion still wet, and it will never work after drying, because dry collodion is a plastic sheet which no longer allows chemical reactions to happen inside.
In modern silver gelatin films you bleach in the first step the negative and then redevelop with strong developers (paper developers, just to say). Gelatine becomes soft and spongy with water and can allow chemical modifications, when wet.
They are two very different processes. I don't think that the former could work in dry silver gelatine. I can't also imagine why it should work. Try. If it it works, let me know.
@@giorgiobordin7779 Thanks for the reply. What's the formula for a bleach tho? I've read some that uses potassium. dichromate and sulphuric acid. I have the dichromate but I don't really want to bother with sulphuric acid. Do you have other suggestion for bleach that's easy to make? Also for redevelopment I've been thinking about pyro developer lately since it stains proportionally. I have all the ingredient to make ABC pyro but haven't tried it yet. You think that will work? Thanks again!
@@Stop4MotionMakr sulphuric acid is less dangerous than potassium bichromate, and is needed, in all formulas. Redevelopment is rough and doesn't require refined developers. A simple Kodak Dektol works fine. I would also be a bit worried about pyro staining for some unexpected odd result.. Another think to try.
Woah