Iron-Copper a direct positive image

[Jan de Jong]

Good evening,

Experimenting further with Copper Sulphate in the Cyanotype process I have stumbled upon a new interesting result.

After some experiments earlier this month with Iron Sulphate, I tried to work on some similar things to see if I can get a direct positive.

What I have done here is all very simple,

Emulsion
- FAC + CU.SO4 + Tartaric acid ( in about ration 1:1:1 where FAC is about 25 gr / 100ml
Dried for 24 hours

- Exposed for 40 minutes under UV light

- Develop with
K-Ferri + K-Ferro + Tartaric acid, about 1gr each in 200ml water.


link to : The Development
- here you will see that after exposure it is a negative image and while pouring the K-ferri-ro mix it changes the unexposed to prussian blue with a very strong contrast.

- Rinse some minutes carefully with tap water.


This scan is taken after 24 hours of drying. Not sure how durable, but for now better than expected.

 

[koraks]

That's brilliant! I love the color contrast you 'automatically' get between the highlights and the shadows.

 

[Jan de Jong]

! I love the color contrast you 'automatically' get between the highlights and the shadows.

Indeed, it is like ceramic glazing on pottery, almost only 2 tones black-blue and yellow-brown

 

[koraks]

Yes, now you mention it; it does look like pottery a bit. Very pretty.

 

[NedL]

Very interesting. Neat looking. I'm not sure what is happening exactly.
I would be interested to know what would happen if you developed with K-ferrocyanide alone.

 

[Jan de Jong]

I would be interested to know what would happen if you developed with K-ferrocyanide alone.

I have the same question, will have to try that next.

 

[Jan de Jong]

Working a bit further on this. Decided to use the sponge to brush away all emulsion that was not so firm attached. I is still drying so have to wait how it will look tomorrow. But it looks we have a direct positive Cyanotype. (but using copper sulfate), so don't know if it still counts as Cyanotype.

anyway I am having fun with it.

 

[Jan de Jong]

and another one with which shows me that grayscale is possible. This is an A4 print, but note the graininess of it.

 

[Jan de Jong]

For the interested reader, another variation. I have tried to get the details as accurate as possible.
Here I coat the paper with following

First coating Emulsion:
1gr FAC
1gr Copper Sulfate
1gr Tartaric acid
20ml Water
Second layer after drying 24hrs
2gr FAC
1gr Tartaric Acid
10ml Water
let dry again

Exposure can be very short, already after few minutes there is enough exposure to have below result.
Here exposure was 4 minutes. This was surprising because this print has over the layer of grass another layer of grass outside the frame which my hope, would be in a diffuse overlay show a sort of 3d effect. But although visible before development it is completely gone. This means that this method must be very light sensitive. Be it that it only produces 1 tone, sort of binary.

After exposure development in bath of
3gr KFerro
3gr KFerri
3gr Tartaric Acid
300ml Water

pour the developer very quick over the print and leave for 1-2 minutes.
pour it back, you can reuse it for about 5-10 prints A4.

Rinse with water and take a soft sponge, like for kitchen cleaning, Brush gently and all the blue will come of and a copper image will be left behind.

Variations of this method can be used to also obtain a blue positive instead of the red copper color.

Because of the overlay of the second emulsion coating the border of the print has some blue.

Regards
Jan.

 

[Jan de Jong]

Some further tests showing the reversal to a very dark blue.
Have to check some different paper stocks because for this process it is actually an advantage when some types of the Cyano blue do easy wash off.


Left - exposed 60min UV light
Right - developed to positive. still wet, will dry in a dull grey-dark-blue.

Here I coat the paper with following

Single coating Emulsion:
4 gr FAC
2 gr Copper Sulfate
1gr Tartaric acid
20ml Water

let dry naturally

Exposure 60 minutes under UV light

After exposure development in bafh of
3gr Ferro
3gr Ferri
3gr Tartaric Acid
300ml Water

pour the developer very quick over the print and leave for 1-2 minutes.
pour it back, you can reuse it for about 5-10 prints A4.

Rinse with water and take a soft sponge, like for kitchen cleaning, Brush gently to remove the non-attached blue dye to leave the attached blue for the final picture