I've got the blues - Cyanotype pain

[gealto2]

Looks really nice and I am glad your making progress. I had severe trouble getting Ware's Simple Cyanotype working last year and never had a desire for NEW,

 

[gealto2]

I just noticed you have a Pixle phone too. I use mine for negative and print scanning all the time.

 

[Raghu Kuvempunagar]

The result is a sparkly, crystal like finish when dry. The is in contrast to using the classic formula or when using the new formula on Arches Aquarelle when dry. Those tend to a matte finish.

This "sparkly" finish has a direct correlation with the properties of the final product.
-The more "sparkly" the finish, the lower the dmax and the more run-off in the wash water.
-The dmax improves with pre-humidification and the sparkly appearance diminishes.
-"Sparkly" surface papers loose much, if not most, of their denisity in plain or a citric acid first wash. Using a mineral acid such as sulfamic acid is a must. This retains the image.
-"Sparkly" surface papers appear to have much of the prussian blue sit atop the paper surface! You can feel the difference between areas of shadow and uncoated areas. The dense areas have a rough texture and tend to leave blue residue on your fingers.

Could the "crystal like finish" be due to residual Potassium Ferric Oxalate in the sensitiser which crystallises on the surface of the paper after coating? During the making of New Cyanotype sensitiser, Potassium Ferric Oxalate crystals form and are removed by filtration. However, as Mike Ware notes in his writings that this separation is not always 100%:

"Of course the separation of potassium from ammonium cations is not 100%: some K+ remains in the solution and a little NH4+ will be in the crystalline product, so the conditions of time and temperature adopted for the crystallization in the following recipe must represent a compromise."

 

[nmp]

What appears to be happening is the water in the solution is readily absorbed by the paper, but the contents tend to get deposited on the surface. The result is a sparkly, crystal like finish when dry. The is in contrast to using the classic formula or when using the new formula on Arches Aquarelle when dry. Those tend to a matte finish.

In a true solution, water can't be absorbed independently from the solute, in this case the sensitizer. All of it is absorbed or none of it. (unless there is reverse-osmosis going on which I don't think it is.)

It is fairly well known that the paper should be matte after it has been dried to get optimum result which is true even for Classic cyanotype. If it is not, it can be due to one of many reasons:

1) the viscosity of the sensitizer is too high so the as you brush it, most of it stays above the paper structure: remedy - dilute the sensitizer, moisturize the paper, add surfactant

2) there is not enough time given to the sensitizer to be absorbed into the paper before it is heat dried. Rule of thumb is to apply heat only after the paper has become matte: remedy - leave the paper in a enclosed box for a time after coating while still wet until it turns matte, only then use blow drying with or without heat

3) if there is too much sensitizer which again leaves out a film above the paper structure: remedy - use less sensitizer, brush excess off with a dry brush, don't leave any pooling of sensitizer on the paper

This "sparkly" finish has a direct correlation with the properties of the final product.
-The more "sparkly" the finish, the lower the dmax and the more run-off in the wash water.
-The dmax improves with pre-humidification and the sparkly appearance diminishes.
-"Sparkly" surface papers loose much, if not most, of their denisity in plain or a citric acid first wash. Using a mineral acid such as sulfamic acid is a must. This retains the image.
-"Sparkly" surface papers appear to have much of the prussian blue sit atop the paper surface! You can feel the difference between areas of shadow and uncoated areas. The dense areas have a rough texture and tend to leave blue residue on your fingers.

Indeed. When the sensitizer is fully dried, it will crystallize into its components. When those crystals are embedded within the paper, they won't sparkle due to scattering. When they are high up above the paper surface, they do. Essentially when sensitizer is sitting on top of the paper, the resulting Prussian blue collodial structure does not have any anchor to hold on to as it is formed so it can get washed away by physical forces during developing. Little UV is available to the sensitizer that might be within the paper fibers underneath so what remains is a much muted blue density.

Best Dmax can be obtained if the sensitizer is sitting right below or at the peaks and valleys of the paper but not too far down. The latter will also result in reduced density.

:Niranjan.

 

[koraks]

Or (4) there are compounds in the paper reacting with the sensitizer, producing insoluble compounds that collect on the surface. I'm leaning towards this as an explanation.

Best Dmax can be obtained if the sensitizer is sitting right below or at the peaks and valleys of the paper but not too far down.

Overall printing as well as coating properties are IME best if the sensitizer doesn't soak in too deeply. I never use surfactants for this reason. They are also a liability w.r.t. clearing the highlights in heavier papers as the sensitizer embeds itself very deeply inside the paper texture and then any insoluble compounds formed there are difficult to remove through washing.

 

[NedL]

Could the "crystal like finish" be due to residual Potassium Ferric Oxalate in the sensitiser

That was my first thought also. But I'm not sure what's going on here

 

[cirwin2010]

Could the "crystal like finish" be due to residual Potassium Ferric Oxalate in the sensitiser which crystallises on the surface of the paper after coating? During the making of New Cyanotype sensitiser, Potassium Ferric Oxalate crystals form and are removed by filtration. However, as Mike Ware notes in his writings that this separation is not always 100%:

"Of course the separation of potassium from ammonium cations is not 100%: some K+ remains in the solution and a little NH4+ will be in the crystalline product, so the conditions of time and temperature adopted for the crystallization in the following recipe must represent a compromise."

Re-reading through Christina Anderson's book, she has brief section about the crystals under the troubleshooting chapter. Her possible explanation is the crystals are from ferric ammonium citrate that hasn't been fully absorbed by the paper.

In a true solution, water can't be absorbed independently from the solute, in this case the sensitizer. All of it is absorbed or none of it. (unless there is reverse-osmosis going on which I don't think it is.)

It is fairly well known that the paper should be matte after it has been dried to get optimum result which is true even for Classic cyanotype. If it is not, it can be due to one of many reasons:

1) the viscosity of the sensitizer is too high so the as you brush it, most of it stays above the paper structure: remedy - dilute the sensitizer, moisturize the paper, add surfactant

2) there is not enough time given to the sensitizer to be absorbed into the paper before it is heat dried. Rule of thumb is to apply heat only after the paper has become matte: remedy - leave the paper in a enclosed box for a time after coating while still wet until it turns matte, only then use blow drying with or without heat

3) if there is too much sensitizer which again leaves out a film above the paper structure: remedy - use less sensitizer, brush excess off with a dry brush, don't leave any pooling of sensitizer on the paper




Indeed. When the sensitizer is fully dried, it will crystallize into its components. When those crystals are embedded within the paper, they won't sparkle due to scattering. When they are high up above the paper surface, they do. Essentially when sensitizer is sitting on top of the paper, the resulting Prussian blue collodial structure does not have any anchor to hold on to as it is formed so it can get washed away by physical forces during developing. Little UV is available to the sensitizer that might be within the paper fibers underneath so what remains is a much muted blue density.

Best Dmax can be obtained if the sensitizer is sitting right below or at the peaks and valleys of the paper but not too far down. The latter will also result in reduced density.

:Niranjan.

I didn't take a picture of the paper prior to exposure, but that edge bleeding really looked like the water was pulling away from the ring of crystal deposits around the edge. Very well could be another explanation such as @koraks.

I have tried diluting the sensitizer, moisturizing the paper, and adding tween20. Admittedly I only used moisturizing/pre-humidification and tween20 in combination. I did not combine diluting the sensitizer with these other variables. As far as per-humidification goes, I'm leaving the paper on some screen above a tray of water. Another try is placed atop and left for several hours before coating. I use this same contraption for post-coating humidification for my kallitypes, but doing it after coating appears to invite paper fog for new cyanotype.

I ran into the same issues with splotches using more or less sensitizer on HPR. I think HPR is just difficult to coat using the new formula.

As long as I can get HPR to continue to coat well using the classic cyanotype formula I still think I'm going down that path. Exposure time vs the new formulation is not that much longer and the dmax is almost as good. Though the color is quiet different using a 20% FAC solution. Very turquoise by comparison.

 

[Raghu Kuvempunagar]

Re-reading through Christina Anderson's book, she has brief section about the crystals under the troubleshooting chapter. Her possible explanation is the crystals are from ferric ammonium citrate that hasn't been fully absorbed by the paper.

But New Cyanotype doesn't have Ferric Ammonium Citrate, her explanation could be for Classic Cyanotype and not for New Cyanotype (Mike Ware does mention that traditional FAC based sensitiser is absorbed poorly: "The traditional sensitizer is poorly absorbed by cellulose paper fibres and some tends to remain on the surface or in the pores." He also says FAO based sensitiser is better in this respect: "Its solution penetrates the fibres of cellulose paper much more readily than the citrate, and it mordants better onto fabrics. It is nondeliquescent. Image substance is better retained.")

I ran into the same issues with splotches using more or less sensitizer on HPR. I think HPR is just difficult to coat using the new formula.

Have you tried giving HPR a rinse in plain water before using it as @Andrew O'Neill does? Or a rinse in mildly acidic water to remove any problematic additive?

Quoting Mike Ware:

"It is possible that this ‘decalcification’ treatment also brings an added hidden benefit: the small anions such as chloride or sulphamate from the acid will tend to neutralise the cationic polyelectrolytes that are present as retention aids"

 

[cirwin2010]

But New Cyanotype doesn't have Ferric Ammonium Citrate, her explanation could be for Classic Cyanotype and not for New Cyanotype (Mike Ware does mention that traditional FAC based sensitiser is absorbed poorly: "The traditional sensitizer is poorly absorbed by cellulose paper fibres and some tends to remain on the surface or in the pores." He also says FAO based sensitiser is better in this respect: "Its solution penetrates the fibres of cellulose paper much more readily than the citrate, and it mordants better onto fabrics. It is nondeliquescent. Image substance is better retained.")




Have you tried giving HPR a rinse in plain water before using it as @Andrew O'Neill does? Or a rinse in mildly acidic water to remove any problematic additive?

Quoting Mike Ware:

"It is possible that this ‘decalcification’ treatment also brings an added hidden benefit: the small anions such as chloride or sulphamate from the acid will tend to neutralise the cationic polyelectrolytes that are present as retention aids"

Ooops, meant to type ferric ammonium oxalate. I edited the original comment to correct that. Sorry for the confusion.

I have not given HPR a rinse. If I was to rinse it in plain water, do I fully dry it before coating? Should the paper be pre-humidified again before coating?

 

[Raghu Kuvempunagar]

Ooops, meant to type ferric ammonium oxalate. I edited the original comment to correct that. Sorry for the confusion.

"Dr. Ware in an email conversation said that if the coating is allowed to stand on the paper without being promptly absorbed, it evaporates and can leave these crystals (possibly of potassium ferric oxalate or potassium ferricyanide)."

This is what @NedL and I suspected. The chances of Potassium Ferric Oxalate forming crystals in the sensitised paper would be higher if during the preparation of the sensitiser, Potassium Ferric Oxalate didn't precipitate fully (green crystals) and some of it remained in the solution.