hardener for gelatine sizing

Hi there,

I want to try printing cyanotypes on organic materials such as wood, feathers and shells. I have tried it so far on wood and a feather without sizing but haven't had any luck getting any detail from negs. I feel it would probably work better if I sized the material first but when I read up on gelatine sizing it requires hardening. Suggestions are Chrome Alum, Formalin or Formaldehyde but these all seem to be difficult to get in Australia. Can anyone suggest a different material for hardening or sizing or know where I can purchase one of these in Australia. There are a multitude of places in the US but I don't want to pay the shipping and I need it relatively quickly. The other thing I have come across is Formalin Melachite which is used for white spot in fish - could I use this instead?

Looking forward to any responses. Thanks

Shani

gel hardener

37% formaldehyde (25ml per 1000ml distilled water ) is prob easiest to get, unless you can find some mercuric chloride(be careful, serious stuff) … better results than alum, more even….

Formalin Malachite will likely give your gelatin a green coloration. My personal favorite hardener is glutaraldehyde - often used by tatoo artists to sterilize equipment. Glutaraldehyde is very potent, fast working, and is much easier/safer to work with than formalin (less fumes). There is absolutely NO REASON to use any mercury compounds.

I haven't tried this with cyanotypes, but for gum printing I use Gamblin PVA size diluted 1:1 with water. I've used gelatin to size, but I find the PVA works better and has none of the fuss associated with gelatin. And none of the hardeners to deal with. As for glutaraldehyde, here's what OSHA has to say:

Short term (acute) effects: Contact with glutaraldehyde liquid and vapor can severely irritate the eyes, and at higher concentrations burns the skin. Breathing glutaraldehyde can irritate the nose, throat, and respiratory tract, causing coughing and wheezing, nausea, headaches, drowsiness, nosebleeds, and dizziness.

Long-term (chronic) effects: Glutaraldehyde is a sensitizer. This means some workers will become very sensitive to glutaraldehyde and have strong reactions if they are exposed to even small amounts. Workers may get sudden asthma attacks with difficult breathing, wheezing, coughing, and tightness in the chest. Prolonged exposure can cause a skin allergy and chronic eczema, and afterwards, exposure to small amounts produces severe itching and skin rashes. It has been implicated as a possible cause of occupational asthma.

Glyoxal and Alum come to mind. Alum is weak though.

Formalin is used by undertakers, so it must be available somewhere.

PE

Shani, I know what you mean about availability of goods in Australia, very frustrating. I can't help you with specific suppliers, but I'd try art suppliers as lots of artists work on paper and a few may practise sizing. I'd stick to either alum or formalin for hardening gelatine, two old standbys. Christopher James in his book Alternative Photographic Processes mentions arrowroot, gesso-acrylic, gloss polyurethane and gum arabic-dicromate as suitable sizing materials.

Chrome Alum should be available in Australia. It is just considered irritant. It is quite free available in the EU. You can even find packs for growing crystals for children. (Aluminum)Alum is also working but much weaker.

Someone like: POCD Scientific ?

Failing that, ebay always seems to be a good source for all sorts of stuff that the general public shouldn't be able to purchase.

Vanbar Photographic has potassium alum which can be bought online: http://www.vanbar.com.au/catalogue/index.php?item1=CHEMISTRY&item2=BULK&brand= I don't know if this form is suitable as a hardener, but might be worth trying. They want $17.60 for 100 grams. They also have many other chemicals, including gum arabic and pot. dichromate I mentioned earlier. Vanbar has always been too expensive in my opinion, but at least they list stock which they don't always have on hand. I prefer to buy all my stuff from American suppliers - cheaper, no problems with 'sorry, we're out of stock' etc, and good service. The Australian market is too small, so retailers have not learned about competition and service. /End of rant. Gold Street Studios in Trentham also has limited stocks of chemicals including chrome alum at $15 for 50 gram (see what I mean?). http://www.goldstreetstudios.com.au/ They are strongly involved in photographic education, particularly alternative processesd. Hope this helps.

Barry

Great, thanks for all the responses. It is great to see such an active forum.

I did eventually email gold street studios to ask the same question as they didn't have any of these substances listed on their website. Ellie wrote back immediately saying she could supply Chrome Alum, Formalin or Fermadehyde so I am going to try the Chrome Alum first and see how that goes. It is a bit pricey but still cheaper then getting from the US when you add the shipping costs. Surely best to start with the least toxic and work from there.

I happily used glyoxal for years and then it suddenly became unreliable and I saw lots of yellowing. New batches of paper and, new sources for glyoxal, and different gelatins didn't solve the problem so I finally embraced formalin. It is nasty, but it works well at very low concentrations, it's absolutely reliable, fast, and clean working (no blue cast like you get with alum), and inexpensive. I use 1% which is only 5 drops added directly to the gelatin for an 8-1/2x11. I size in a garage and at that concentration fumes are not noticeable.