Simple Cyanotype

[SEArtEric]

Perfect! I was thinking the two-part longevity method was to simply not mix in the potassium ferricyanide until needed.

Every science begins as philosophy and ends as art…
…Science is the captured territory; and behind it are those secure regions in which knowledge and art build our imperfect and marvelous world. Philosophy seems to stand still, perplexed; but only because she leaves the fruits of victory to her daughters the sciences, and herself passes on, divinely discontent, to the uncertain and unexplored.
– Will Durant, The Story of Philosophy (1926)

Well wishes Dr. Ware, always a pleasure.

Eric
https://specialeditionartproject.com

 

[awty]

Very nice work Eric.
I thought ammonia would be easy to get, but I can only find one distributor here that sells 25% by the 5ltr container. What am I going to do with 5ltrs of the stuff, already in mortal fear that the police are going to break down the door to my dark room thinking its a meth lab.

 

[MattKing]

I thought ammonia would be easy to get, but I can only find one distributor here that sells 25% by the 5ltr container. What am I going to do with 5ltrs of the stuff,

Clean a lot of really dirty floors?

 

[awty]

Clean a lot of really dirty floors?

Thats a great idea, was looking for a gift idea for my wife's birthday!

 

[Mike Ware]

World Cyanotype Day
Land / Sea / Sky
Saturday, September 28th, Two Thousand and Nineteen

To accompany Eric's contribution to World Cyanotype Day, here is one of mine that seems to fit the brief:
'Rackwick Bay, Hoy, Orkney 1984'
Mike Ware. Simple Cyanotype 2019

 

[awty]

I just made up a brew, fingers crossed.

 

[ProfessorC1983]

Very excited to try out this process!

Is it possible that Triton X-100 could be substituted for Tween 20 as the surfactant?

 

[fgorga]

Very excited to try out this process!

Is it possible that Triton X-100 could be substituted for Tween 20 as the surfactant?

If I were a betting man, I would bet that Triton X-100 will work just fine as a substitute for Tween 20.

That said, why bother?

Tween-20 is cheap and easy to obtain.

I recently used up the last of a 10% Tween 20 stock that I made years ago when I had access to a lab. (I retired from a career as the chemistry professor almost 7 years ago.) Needing more, I turned to Amazon and ordered this: https://www.amazon.com/gp/product/B01FY41OOM/

Regards,

--- Frank

 

[Mike Ware]

Very excited to try out this process!

Is it possible that Triton X-100 could be substituted for Tween 20 as the surfactant?

I've never used Triton X-100, so cannot give a definitive reply; however, both surfactants are non-ionic (which I think is most desirable to avoid interactions with a highly ionic sensitizer) and they have similar polyoxyethylene hydrophilic chains. The hydrophobic co-polymer chains differ. Tween may be more benign, environmentally speaking, if you are feeling very scrupulous, because Triton X-100 has been listed as a "substance of very high concern". However the amounts we use are negligible compared with other uses of this surfactant.
I won't be taking Frank Gorga up on his wager... let us know please, if you try it, how well it works.
Best,
Mike
www.mikeware.co.uk

 

[jisner]

I recently made up 100 cc of Simple Cyanotype, specifically the "separated for longer shelf life" version. I need a short Exposure Scale, so I followed the high contrast instructions. I made "part A" (anhydrous CA, purified water, 28% laboratory grade ammonia, and Ferric Nitrate). The next day, I made a working solution of 20 ml part A + 20/9.5 = 2.11g Potassium Ferricyanide. It prints beautifully on Arches Platine. However...

With a short (30 second) 1% CA acid bath, I got an ES of 2.10. I determine ES by substantially overexposing a Stouffer TP4x5-31 in order to be able to identify EMax and EMin.

With an 0.25% CA acid bath, the ES was unchanged.

With plain water development, the ES dropped to 2.00.

I am washing for 10 minutes in 6 or 7 static baths of tap water softened with 2 drops of 40% CA per liter of water. Our water is very hard.

I am considering switching to Simple Cy as a replacement for New Cy, mainly because of the shorter ES. I would really like to get the ES down to a maximum of 1.80. Any suggestions?

 

[fgorga]

I recently made up 100 cc of Simple Cyanotype, specifically the "separated for longer shelf life" version. I need a short Exposure Scale, so I followed the high contrast instructions. I made "part A" (anhydrous CA, purified water, 28% laboratory grade ammonia, and Ferric Nitrate). The next day, I made a working solution of 20 ml part A + 20/9.5 = 2.11g Potassium Ferricyanide. It prints beautifully on Arches Platine. However...

With a short (30 second) 1% CA acid bath, I got an ES of 2.10. I determine ES by substantially overexposing a Stouffer TP4x5-31 in order to be able to identify EMax and EMin.

With an 0.25% CA acid bath, the ES was unchanged.

With plain water development, the ES dropped to 2.00.

I am washing for 10 minutes in 6 or 7 static baths of tap water softened with 2 drops of 40% CA per liter of water. Our water is very hard.

I am considering switching to Simple Cy as a replacement for New Cy, mainly because of the shorter ES. I would really like to get the ES down to a maximum of 1.80. Any suggestions?

Bottom line... Prussian blue (the pigment in cyanotype) is quite sensitive to alkaline hydrolysis.

Thus you have discovered (as did I, see: https://www.photrio.com/forum/threa...the-washing-of-traditional-cyanotypes.177366/) adding acid to your washes if you have hard water increases Dmax and tends to give better mid-tone contrast.

I would guess that if you want to decrease Dmax further remove the citric acid from your washes and see what happens.

You can probably further decrease Dmax by increasing the pH of your first wash using sodium bicarbonate (baking soda) or sodium carbonate (washing soda). Bicarbonate is a weaker base than the carbonate and so should have a lesser effect (at similar concentrations) than the carbonate. As to what concentrations to use... you'll need to experiment. You will know if you are using too much... your nice image coming our of the printing frame will fade badly when it hits your first tray.

 

[jisner]

Bottom line... Prussian blue (the pigment in cyanotype) is quite sensitive to alkaline hydrolysis.

Thus you have discovered (as did I, see: https://www.photrio.com/forum/threa...the-washing-of-traditional-cyanotypes.177366/) adding acid to your washes if you have hard water increases Dmax and tends to give better mid-tone contrast.

I would guess that if you want to decrease Dmax further remove the citric acid from your washes and see what happens.

I'm not concerned about DMax. I want a shorter exposure scale. According to Mike Ware, I should be getting an ES of 1.8 with a 1% CA acid bath and 1.3 with no acid bath. I'm not getting anywhere near that.