Cyanotype: concerned about the smell

Tetium · Dec 10, 2016

Hello everyone,

I have a bizarre question to ask you about the cyanotype Mike Ware new formula.

You certainly already have noticed the smell of the solution right after you open the bottle of formula.
A strong smell of chemical compounds, impossible to determine, am I right ?

When I open the print frame right after exposure, I can smell a strong odor.
This is the same odor of the bottled formula but a little stronger, probably due to the heat of the UV lamps.
It disappears quite rapidly, but the smell is potent at the time it is present.

I am concerned about my safety, and I would like to know if that is a normal reaction, or if it is dangerous.
(???)

(My UV light box is pretty fast, I fully expose a cyanotype in 3 minutes maximum.
The sheet is at 10cm from the UV tubes, I always have a very good insolation with no problems and a very good sharpness with this construction).

Thanks for your informative answers.

railwayman3 · Dec 10, 2016

I use the original cyanotype formulae and sometimes the prepared papers which can be purchased (particularly if I'm letting the grandchildren have a go (under supervision) at making photograms).
The new formulae on Mike Ware's site uses an oxalate compound and states "This sensitizer solution is poisonous (much more so than traditional cyanotype) and it will obviously stain skin, wood, clothes, textiles, household pets and any other absorbent surface", so I would certainly approach this with caution and not use it when children were present.

Tetium · Dec 10, 2016

The Mike Ware's new formula is indeed poisonous because of the oxalate compound and the ammonium dichromate.
I would not use it if children were present of course.

I am particularly concerned about the smell,
that characteristic odor that is present when I open the UV box.

ransel · Dec 11, 2016

When I open the print frame after exposing (classic formula) there is a strong smell. Did I not read that the chems produce cyanide gas?

edit - yes, I just read in an older APUG post that temps above 150° F can cause the release of the gas - potassium ferricyanide.

I know when I was printing this past summer on my front porch, the 5 minute exposures made the paper in the printing frame quite hot. I'll have to do a temp test next printing session.

Halford · Dec 11, 2016

Hi all, I don't know what exactly the smell if you're detecting, but just to set your minds at rest -- oxalate is poisonous but not volatile -- i.e. it can make you ill if you ingest it, but doesn't produce a significant vapor. Dichromates are all extremely toxic but once again -- not volatile. Cyanide is toxic and volatile but the ferricyanide ion is not the cyanide ion, and potassium ferricyanide is not a gas. So in the same way that sodium metal is explosive and combustible, while the sodium ion is relatively harmless and found in all our food, cyanide and ferricyanide, while both containing C-N functional groups, have very different chemical and biochemical properties.

It's very possible that ammonia gas is generated in these processes, and it is not very dangerous, though you shouldn't work with it in enclosed spaces. The amount of cyanide that could conceivably be released from a print (if any is at all) is also very unlikely to be a serious health concern.

Short version: There probably isn't too much that should overly concern you when you open the printing frame but that said, good ventilation is a very good idea whenever you work with chemicals.

However: Any solution containing dichromate, should be considered very harmful, treated with great care and disposed of as heavy metal waste through proper channels. It is both an acute and chronic poison to human bodies, and extremely harmful to the environment.

Halford · Dec 11, 2016

Just following up on this -- there's no dichromate in Mike Ware's cyanotype formula either, so I'm not sure how that came into the discussion

The only toxicity is from the oxalate with, as I said, is not volatile. The smell is probably mostly ammonia.

ransel · Dec 11, 2016

Halford, thanks for the info. The other APUG post I read, from 2013, stated "Just don't heat the ferricyanide above 150 degrees C, or mix it with a strong acid. That would break the bond between the iron and the cyanide and release a cyanide gas." So, is this incorrect?

I know what household ammonia smells like, and the smell I get when opening my contact print frame is not that. Is there other ammonia smells?

Also, from this link - http://www.nontoxicprint.com/safetyinphotography.htm

The key compound needed in Cyanotype chemistry - potassium ferrocyanide - is falsely thought of as safe. Many think of this common iron salt as harmless because it can safely be ingested. The US food agency (FDA) declared the chemical safe in the 30s, based on knowledge available at the time. Yet on contact with UV light or acids, or heated to mid-summer temperatures the compound can break down and release hydrogen cyanide gas (HCN) that can be as toxic as nerve gas. Ferrocyanide has even been implicated in terrorism.
Ferrocyanide is not to be confused with the iron cyanide molecule of its relative Prussian Blue (or the printing ink Cyan) which has a very stable and much more inert chemical structure. The nontoxic compound is used in ink, paint, and pigment making, and in certain medications. Only experts can fully explain the subtle but highly significant differences between the various blue cyanides that are used for these different applications.

The professional use of small amounts of ferrocyanide in the food industry and for medical applications may not be of concern. However, it is questionable if amateurs should be advised to use dry ferrocyanide powders or bottled cyanotype formulations as a staple ingredient in their practice. Making photographic prints and decorated fabrics with the Cyanotype process, and the reactive chemistry it entails, carries very significant risks.
The EPA reported a case where an unsuspecting amateur photographer made printed quilts treated with cyanotype chemicals as a hobby, and then suffered permanent facial injuries as a result of what was believed to be possible exposure to cyanide vapors and/or chromium compounds. The EPA warns: '...the hexacyanoferrates used in cyanotype, blue print, and in Prussian blue pigment should be considered true cyanides.'

AgX · Dec 11, 2016

Oxalate is an ingredient in some foodstuff. As with many potions it is a matter of quantity.

AgX · Dec 11, 2016

Kaliumhexacyanidoferrat(III)

The temperature at which it decomposes, splitting off HCN, is above 300°C.
The odour is described differently.
Such temperature is hardly achieved during handling for cyanotyping.
I know an MSDS where that heating issue is not even hinted at.

We should also keep in mind that there is another common houshold thread: mixing chlorine-bleach with other (acid) cleaning agents.

pdeeh · Dec 11, 2016

ransel said:
Also, from this link - http://www.nontoxicprint.com/safetyinphotography.htm

The key compound needed in Cyanotype chemistry - potassium ferrocyanide - is falsely thought of as safe. Many think of this common iron salt as harmless because it can safely be ingested. The US food agency (FDA) declared the chemical safe in the 30s, based on knowledge available at the time. Yet on contact with UV light or acids, or heated to mid-summer temperatures the compound can break down and release hydrogen cyanide gas (HCN) that can be as toxic as nerve gas. Ferrocyanide has even been implicated in terrorism.
Ferrocyanide is not to be confused with the iron cyanide molecule of its relative Prussian Blue (or the printing ink Cyan) which has a very stable and much more inert chemical structure. The nontoxic compound is used in ink, paint, and pigment making, and in certain medications. Only experts can fully explain the subtle but highly significant differences between the various blue cyanides that are used for these different applications.

The professional use of small amounts of ferrocyanide in the food industry and for medical applications may not be of concern. However, it is questionable if amateurs should be advised to use dry ferrocyanide powders or bottled cyanotype formulations as a staple ingredient in their practice. Making photographic prints and decorated fabrics with the Cyanotype process, and the reactive chemistry it entails, carries very significant risks.
The EPA reported a case where an unsuspecting amateur photographer made printed quilts treated with cyanotype chemicals as a hobby, and then suffered permanent facial injuries as a result of what was believed to be possible exposure to cyanide vapors and/or chromium compounds. The EPA warns: '...the hexacyanoferrates used in cyanotype, blue print, and in Prussian blue pigment should be considered true cyanides.'

The author of this does not inspire much confidence, as s/he refers to ferrocyanide throughout.

Ignorance is bliss, I suppose, until it leads to making a lot of bollocks proliferate on the internet.

cretinous idiocy

Prof_Pixel · Dec 11, 2016

ransel said:
I know what household ammonia smells like, and the smell I get when opening my contact print frame is not that. Is there other ammonia smells?'

Cyanide sometimes is described as having a “bitter almond” smell, but it does not always give off an odor, and not everyone can detect this odor.

nmp · Dec 11, 2016

ransel said:
Also, from this link - http://www.nontoxicprint.com/safetyinphotography.htm

The key compound needed in Cyanotype chemistry - potassium ferrocyanide - is falsely thought of as safe. '

Cyanotype uses ferri, not ferro, cyanide. Something amiss?

Edit: Looks like pdeeh caught that one before I did

nmp · Dec 11, 2016

Halford said:
Just following up on this -- there's no dichromate in Mike Ware's cyanotype formula either, so I'm not sure how that came into the discussion

The only toxicity is from the oxalate with, as I said, is not volatile. The smell is probably mostly ammonia.

There is a small amount (0.1%) of ammonium dichromate in Mike Ware's original formula.

Tetium · Dec 12, 2016

The Mike Ware’s new cyanotype formula I use (from his website) includes :

Ammonium Iron(III) Oxalate (NH4)3[Fe(C2O4)3].3H2O
Potassium Ferricyanide K3[Fe(CN)6]
Ammonium Dichromate (NH4)2Cr2O7

So there is a small amount of Ammonium Dichromate, about 0.1gr. to make 100 ml of formula.

Halford: The smell I detect is the same I can smell when I open the bottle of formula, but much stronger, maybe something like ammonia but not strong as the household ammonia.
Nothing to do with the famous « bitter almond » odor. I think…

The odor is very volatile, it tends to disappear in less than a minute.

My UV box can be quite hot, but not as much as the described temperatures.
I let the sheet in there for 3 minutes maximum.

Cyanotype: concerned about the smell

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