Cyanotype printing

Recently I spent some time for testing and comparing a 'traditional' cyanotype receipt with the 'new' sensitizer solution and an UV lamp vs. sun printing.

I did a traditional mixture of ferric ammonium citrate and potassium ferricyanide. This receipt was originally  invented by Sir John Herschel in 1842 and today is considered as a cheap and easy, mixture for beginners ;) (you can find a receipt here )

My previous prints, I presented so far, were printed with a ready to buy Fotospeed Cyanotype Sensitizer. This type of improved formula uses toxic ferric ammonium oxalate and is a bit more complicated to prepare, but claims to give better prints. As, what I had was only 50ml bottle and finished quite quickly, I decided to buy the chemicals and to try and prepare the traditional mixture, by myself.

The other thing that bothered me was printing with the sun in winter.
Well, actually printing with the sun generally. It is very pleasurable, but very restricted by the weather (especially in IE), exposure time varies, depending on weather conditions, time of the day and year season.
I did a research regarding UV lamps.

I took a few options into consideration -  face solarium, fluorescent  lamps (aqua), halogen lamps and decided to try the last and probably cheapest option. I went for a security, 400W, lamp, that you usually use as an external lamp, outside your house.

I did a series of prints of the same neg (for comparison) with the rest of Fotospeed chemistry, my new mix, the lamp and the sun.

First one is the original print I’ve made with sun, a while ago, 10 min exposure, with Fotospeed Cyanotype sensitizer /one of my best prints, I was aiming for similar results/ :

Fotospeed chemicals, first use of lamp, 20 min exposure , (it works! but exposure looks too short, unfortunately sentisizer ended with this print):

Third one is a new mix of chemistry, printed with lamp, 55 min. exposure / very high contrast, but I lost the details of the mountain in the background/ :

Lamp, 1 hour and 30 min / too dark/ :

Lamp, 1hour and 10 min:

....and this is a time that gives me best results with the lamp. The contrast is fine and details look OK.

check with different negative:

Generally the conclusion is that the two mixes of chemistry, I tested, work visibly differently. I have to admit that the 'new' formula gives much wider tonal range, with any negative, and seems to work much quicker.
The traditional receipt gives bigger contrast, and it is very important to use it with negatives, with soft tones (contrasty negs give poor results). 
Since that time I did a set of prints, that I'm quite happy with. I learned what type of negative to use to get a good print and I quite like the results. I'm going to stick to my current technique for a while (at least until my chemistry will finish).

I will show the further results in the next post, for your comments...