Last thought for the night. I made up 2 new batches with distilled water this time. It still painted on the paper with a pale de-saturated blue-green. Not the distinct yellow like in the youtube videos. This time I use the backside of some very old Kodabromide single weight paper. It just doesn't paint on as nice as the videos with watercolor paper. It's like the paper won't "take" it unless I were to put a dash of photo-flo in it.
Coating paper with cyanotype (or really any alt process) sensitizer is a balancing act. One needs the sensitizer to soak into to the upper layer of the paper but not soak in too far.
Thus surfactants such as PhotoFlo, or more commonly Tween-20 are a mixed blessing. They are needed for some papers but detrimental with other papers. There is no way to know how a new paper will react without experimenting.
That said, your statement that the coated paper is a 'pale blue-green' is an indication that there is something in that particular paper that is reducing some of the iron in a non-light sensitive reaction and thus it is not suitable for cyanotype. There are many papers that react similarly and the only solution is to move on to a different paper.
So I guess my idea of salvaging old photo paper was a bad idea. I also think the citrate powder has gotten old and maybe a bit oxidized.
This makes no sense chemically the iron in FAC is already in the oxidized "ferric" [i.e. iron(III)] state. There is a further oxidized form of iron [iron(IV)]. However, converting iron(III) to iron(IV) requires extreme conditions (e.g. very high temperature) which are unlikely to be seen under typical storage conditions.
I am quite sure that your ferric ammonium citrate stock is quite useable.
So much for "getting out cheap". I'll make some more test prints tomorrow, but I think It's a fool's economy.
Agreed!!!
When you get back to this, please post a photo of the ferric ammonium citrate (FAC) powder you're using.
Did you weigh everything out correctly? Your FAC solution looks too concentrated to me. The color seems plausible for a very concentrated solution; more so than what you'd typically use for cyanotype. I prefer to store solutions in clear glass bottles and then store those in the dark. It helps seeing the colors better; it's easier to notice if anything's off.
FYI for the OP... the 'traditional' concentrations of the stock solutions are 25% (w/v) for ferric ammonium citrate and 10% (w/v) for potassium ferricyanide. In other word 25 g / 100 mL of final solution and 10 g / 100 mL of final solution respectively. These are then mixed together in a 1:1 by volume ratio to make the photosensitive sensitizer.
More recently, some folks (including yours truly) have gone to using 10% (w/v) stocks of both compounds. These are still mixed together in a 1:1 ratio by volume.
I've found the "New Cyanotype" chemistry to be very fussy and unpredictable. I stopped trying to work with it. It seemed to me that the more expensive the paper you used, the more likely your results would be garbage. It just washes off Canson Platine and Hahnemuhle Platinum Rag papers. If I were to do any cyanotype work these days, I would use the old recipe - I found it consistently reliable and easy to work with. .
The New Cyanotype formula is sensitive to paper chemistry, and I've also found it requires a strong acid being added to the first rinse for its tonal scale to develop properly. It's certainly more iffy than the classic chemistry.
Fully agree with both of the above comments.
I find (using digital negatives) that the traditional cyanotype and 'developing' with an initial bath of 10% (v/v) vinegar before switching to tap water gives perfectly acceptable prints.