SPP Saidane's Print Process

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For anyone who hasn't watched his videos:



Habib Saidane developed a simple formula based on Ferric ammonium citrate to replicate the Gum bichromate process.

He mixes a certain amount of CMC carboxymethylcellulose, gum Arabic, water and FAC to make an emulsion which you then mix with a pigment to create a sensitized coating on watercolor paper.

I've tried and tried to replicate the process using ~380nm -390nm uv sources but so far not much of a success but I though to maybe share some experimental results. I'm not a chemist and I do this as a hobby trying to not learn much more than necessary. I am an opto mechanical engineer, but again don't intend to do much more than helping pass the word and experimenting with whatever I can find.

 

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As a first thing to share:

Making CMC from powder is not a simple hand mixing. Do your mixing, let it sit for an hour and come back and mix some more. Do that a few times and let it sit overnight. Its really viscous stuff and I think its the same stuff I used to put on my hair to style it when I was a kid.

Saidane has stated that gum doesn't harden by itself but CMC by itself can work. I personally have done some experimenting and found that both can harden via FAC + UV, but both remain dissolvable in water or 0.3% peroxide water.

I added a couple of grams of Sodium Benzoate to the mix when I first mixed my current batch almost the same week Habib put up the first video. So its been a few months? And the stuff is still nice and clear. Sodium Benzoate is supposedly a weak photo initiator, so that's why I had it around to try. It is used as food preservative so that's why it made sense to try. Without it, the CMC developed mold after a week in a closed glass jar. Habib has since changed to dry mixing in small batches. But the liquid should work too.

Finally, I found out yesterday that if you add more pigment and CMC than necessary it actually dissolves the exposed areas first leaving you with a positive rather than a negative of the image. Yet the real problems I've found are that the stuff will dissolve completely if you just develop it in 0.3% peroxide and continue to keep it submerged. Drying, the image runs and becomes not an image. I'm certain I'm doing all sorts of incorrect stuff. But one thing I've done so far is to warm up the peroxide before developing per Habib's instruction.

 

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Since giving up on actually making an image and focusing solely on trying to make the process work, I've resorted to using a simple 25w LED lamp to experiment on small pieces of water color paper. I use coins and washers to make a shadow image to develop. Here's an example of the negative images I've been able to make and the look of it before dunking it in peroxide.

 

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Since giving up on actually making an image and focusing solely on trying to make the process work, I've resorted to using a simple 25w LED lamp to experiment on small pieces of water color paper. I use coins and washers to make a shadow image to develop. Here's an example of the negative images I've been able to make and the look of it before dunking it in peroxide.

And here is a positive image

 

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For your and my info in the future, I got the recipes below:

On the first video:

he makes:
1) 100ml of 2% CMC so a total of ~2g in 100ml liquid
this mix is made in 60C water and you mix it until you get tired and then just let it rest overnight.

He says the Gum Arabic is for emulsifier and binder both of which I highly doubt are actually needed in CMC but alright...
2) get 400ml of water + 200g GA and mix. Add a preservative

3)Ferric Ammonium Citrate:
Mix 25g in 100ml water
Add a preservative

4)Developer 0.3% hydrogen peroxide
9 parts water to 1 part H2O2 @3% makes 10 parts of 0.3% H2O2

Emulsion Mix:
2parts 2% CMC
1part GA
1part FAC

For 100ml:
50ml CMC or 1g
25ml GA or 12.5g (reduced in the second video)
25ml FAC or 6.25g (reduced in the second video)


The recipe on the 2nd video:

with dry ingredients is:

For 100ml:
1gr CMC or 1gr Methylcellulose (powder)
10gr Gum Arabic (powder)
5gr Ferric Ammonium Citrate (powder)

100ml of distilled water.
Directions:
a) Expose in warm temperature environment 20°C or better
b) Develop in 0.3% Hydrogen Peroxide at around 35°C
c) Rinse in warm water at around 35°C

 

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Per one of the AI tools:

Compound | Molecular Weight (g/mol)
--------------------------|-------------------------------
Carboxymethyl cellulose | 17,000–800,000 (polymer avg.)
Ferric ammonium citrate | ~368
Ferric ammonium oxalate | ~285
Gum arabic | 250,000–600,000 (polymer avg.)

I tried asking what if any reaction there would be using UV to expose the mix.
According to this AI there would be none with either or both ingredients, CMC or GA. However I asked about adding Sodium Benzoate because of some research and it lead me to this doc:

https://ri.conicet.gov.ar/bitstream...ro.a11ce4b8-0138-46d8-8488-d845048eb28a_D.pdf

which says that indeed ther would be a UV reaction using that. It also suggested trying ammonium persulfate, but that seems too dangerous to have at home.

 

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LOL! Holy smokes! Okay, I had Sodium Benzoate around since I was playing around with CMC and I totally dismissed it as photoinitiator previously after doing a variety of tests. But this time I simplified the test. Sam emulsion without SB will just dissolve. SB makes it even have Carbon transfer-like relief. and the edges are sharp, not runny. Previously I had added SB in tiny amounts because it would bubble a lot when adding FAC.

 

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Wait up....that's a really strong positive image! What?? I didn't even realize it until just now. I was expecting to put the coins on the the paper, expose and then get a black paper with little round holes. instead it looks like the UV make the exposed parts dissolve away so this would be a positive working emulsion. Well I'm going to let this sample dry overnight and then tomorrow morning my plan is to make a different color and see if I can get the color on without ruining the image below. Then I'll try an image.

 

[xiaruan]

I tried this method. After adding hydrogen peroxide, there would be an image. However, during the subsequent rinsing process, all the pigments would be washed away.

 

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I tried this method. After adding hydrogen peroxide, there would be an image. However, during the subsequent rinsing process, all the pigments would be washed away.

That was exactly my problem. But now if you add sodium benzoate it seems to make unexposed CMC insoluble while exposure CMC seems to dissolve fast.

 

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I was able to create images with other colors and can confirm that covering one color with a new brushed on coat doesn't dissolve the first layer. That said, there are issues. I made this red color image and quite a few test images in other colors and various combinations of CMC, Arabic Gum, Ferric Ammonium Citrate, Sodium Benzoate, Citric Acid, Sulfamic Acid, Ferric Chloride, peroxide, HCL etc. I started identifying stuff that seems to work and stuff that doesn't. So what I have left is:

Mix:
1 vol of 2%CMC
1 vol of pigment
1 vol of sodium benzoate
1 vol of Ferric Ammonium Citrate

Develop in warm (25 to 35C) 0.3% hydrogen peroxide

Expose for 3 minutes to get the positive image ( exposed stuff dissolves away) or 16 minutes to get a negative image (exposed stuff stays, everything else dissolves). And this is where I am at. Not sure exactly why it works how it works.

What am I using? (all is from amazon)

1) 9oz CMC Powder, 100% Pure Food Grade CMC Powder, Tylose Powder for Fondant, Ice Cream, Cake, Yogurt, Candy & Gum Paste, Premium Carboxymethylcellulose Food Thickener and Moisture Retainer
Brand: Vividye


2) Bluebird Premium Poster Paints 3.4 Fl Oz / 100ml Set of 6 - Vibrant Primary Colors for Stunning Artwork and Creative Projects
Visit the Bluebird Store

3) Spicy World Sodium Benzoate 8 Oz - 99% USP/FCC Grade, Additive and Preservative
Brand: Spicy World

4) Ferric Ammonium Citrate(Green),for Cyanotype(500g/17.6oz)
Visit the EASTCHEM Store

 

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So you either get a positive by exposing for 3 minutes or a negative by exposing longer like 16 minutes. I'm not fully sure what is happening but here are images done with the same batch and different exposures:

 

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Okay...The positive image was not due to less exposure. I just tested a new batch and it just floats away at 3minutes. This was CMC only. Maybe Gum Arabic did play a role in this. I just realized that I changed the pigment too on the test this morning. I added graphite to the poster color. hmm. So many variables. at lest though, it seems that the negative working part was constant in my last experiment.