cyanotype and adding dichromate

[philldresser]

Don't coat under red light, you only don't see what happens. Weak normal bulb light is completely adequate, though it is probably better to avoid tubes. You want to see and check the sensitizer and the surface clearly when coating.

20?

I agree here. Use normal tungsten lights (Mine is 60 watt @ 1.3 meters. No problems with 20 min exposure. However the tubes in the garage/darkroom cause density after 3 mins.

Phill

 

[Willie Jan]

i did a test and the liquid is very very light green.

The photo on alternative.com with cyanotype how to coat the paper picture where the guy who is using a glass rod to coat the paper shows a pale yellow, but this is not the case with mine ( i think he used something else..).

I glass rodded a little piece of fabriano and bergger cot 320. After coating and drying the cot 320 looked a little more green than the fabriano. Next day the cot did turn towards the blue and the fabriano stayed as before.

But what i did wrong was that i used the backside of the cot 320 paper... So i will do the test again this evening with the right side up to see what happens...

 

[Willie Jan]

i did a new test on the bergger 320 (on the right side of the paper).

It was light green after drying, next morning it still was light green.

Conclusion:
This would mean that the cot 320 is appropriate for this job.
The fabriano turns towards blue after one night.

Or is there paper where the liquid stays yellow?
The Blueprint to cyanotypes book says that it turns light green and it does.

Willie Jan.

 

[Lukas Werth]

Willi Jan,

the Bergger paper is inadequate, don't use it for this process, at least not untreated. The sensitizer has to remain yellow when dry, as it must appear once you coated it on the paper, or otherwise the image will be fogged. (By the way, this means that the paper may not really be first-rate for other iron-salt processes, too)

Blue is worse than green, but that result on untreated Fabriano (artistico, isn't it?) was predictable, since this paper contains an alkaline buffer, as do most papers today: this is a selling argument to make them more resistant against environmental damages.

You may try to immerse both papers in 1% hydrochloric acid for about 5-10 minutes, with occasional rocking, wash the acid out in a short clear water bath, dry, and then coat again. Very likely you will find that the sensitizer remains yellow in this way, but with Fabriano Artistico I still have often problems with blotches appearing only after the paper has been exposed under the negative. Sometimes, if you are lucky, they wash away when you give the first wash in 1-2%hydrochloric or (I think?) nitric acid, but often enough they don't, enough to make the printing experience with such papers frustrating. I now use Fabriano treated in such way for test strips, as I don't want to waste the expensive Buxton in this way.

By the way, I don't seem to know the book you refer to. What is its exact title? And, I would think that for traditional cyanotypes also, the sensitizer has to remain yellow if you want first-rate results (and otherwise, why bother?).

 

[Willie Jan]

this is the book.

http://www.alternativephotography.com/books/cyanotypes.html

I'll try it with the acid.
1% solution. The chemical is delivered here as 30% solution,
so i must add 3ml acid at 97ml water?

Willie Jan.

 

[Lukas Werth]

The chemical is delivered here as 30% solution,
so i must add 3ml acid at 97ml water?

This should do. Try it for both papers, and watch for the bubbles to disappear before taking the paper out again to rinse it. When you coat, at least for the Fabriano I would use some Tween 20.

 

[Willie Jan]

Lukas, i tried it with the hydrogloric acid (called 'zoutzuur' here).

The bergger paper after coating/drying still was yellow. The fabriano also. The next morning the berrger was still yellow, the fabriano a little more greenish.

Thanks for your help.
In the weekend i will make some prints to see the difference.....

Willie Jan.

 

[Lukas Werth]

The bergger paper after coating/drying still was yellow. The fabriano also. The next morning the berrger was still yellow, the fabriano a little more greenish.
Willie Jan.

I will be interested to learn about your results. Maybe you can bring the Bergger paper into service this way. When you print, I think it is best to expose the paper as soon as possible after coating. Heat-drying serves well, and does no damage. Don't store coated papers, and don't keep them over night.

 

[Willie Jan]

photos where taken after 24 hours of drying (dark).

 

[Lukas Werth]

Thank you, this is instructive!
Well, the Bergger paper seems to be better than the Fabriano without prewash.

However, 24 hours before exposure seem far too long in any case. Even the prewashed ones would not be fit anymore for exposure. When you expose the paper, the colour of the sensitizer should be yellow. A very light greenish tinge *in the yellow* may be aceptable - may happen with a sensitizer with much citric acid added for very low contrast, or when the gods of the blues are not with you - but no more.

 

[Willie Jan]

when the cot 320 was just dry after 10 minutes, the color was yellow. So when coating & lightning is within a couple of hours, it would be ok.

Is the buxton paper so good that it stays yellow?

 

[Lukas Werth]

Is the buxton paper so good that it stays yellow?

I don't think so, but i suppose this is less a question of the paper than of the sensitizer itself. If you keep Buxton or other papers under conditions of very low humidity, i.e. with silica gel in a sealed container, it should keep fresh (stay yellow) much longer.

What remains to be seen is whether the final picture will be okay, that is without major irregularities (blotches or such like). This is also where superior paper quality comes in.

 

[Davec101]

Have been following this post with interest and wanted to ask where someone from the U.K gets Bergger and Buxton paper as i am having troble finding it, many thanks

 

[Willie Jan]

Buxton can be bought directly from http://www.ruscombepaper.com/
Bergger cot 320 from Belguim Dead Link Removed
france: http://www.galerie-photo.net/

i haven't found any shops in england...

 

[Willie Jan]

Lukas,

i did a test where two test strips were lighted the same time for the same negative.

First one was washed in a vinegar solution and the second in hydrogloric.
the hydrogloric one turned full blue, the vinegar one showed light blue.
I will post the result here end of the day.

 

[Willie Jan]

here is the test.
the darker image is after the lightning processed with hydrogloric acid. the other one with water & vinegar.

Both papers were lighted at the same time and for the same duration.
I left them for +/- 48 hours before i scanned them.

Willie Jan.

 

[Davec101]

Left one looks good to me, Good work,now i need to get me some hydrochloric acid!

 

[Lukas Werth]

Yes, the difference is obvious. Willie Jan, have you used a 1% solution of hydrochloric?
This test strip result shows the virtue of mineral acid for New Cyanotypes. Bear in mind that Mike Ware in these days recommends nitric acid, though I don't think this makes a difference to hcl for the final result.
Let me ask a few more questions, just to make sure:
Have you used a contrast agent (am di) in your test strip, or citric acid to lower contrast?
Was the dried sensitizer yellow on the paper when you exposed it?
Did you expect these flowers to be white/would they be near-white in a normal bromide print, or are you happy with the light blue?
I ask because, to be perfectly honest, as far as I can see on my screen, the test strip still looks a bit veiled, and the blues in the shadows could be darker. But to state anything further here, it is necessary to know the artist's intentions/the whole picture/about the quality of the negative.

 

[Lukas Werth]

Just an additional thought: for a test strip at this stage, it might be informative to not completely cover it with the neg, but expose also a piece of "splatter border" This is always the last to recover from solarisation, but should show a blue very near to black in New Cyanotye (as in well executed traditional, if you ask me).

 

[Willie Jan]

Yes, the difference is obvious. Willie Jan, have you used a 1% solution of hydrochloric?

Yes.

Have you used a contrast agent (am di) in your test strip, or citric acid to lower contrast?

No, i still have some cyanotype left without the contrast agent.

Was the dried sensitizer yellow on the paper when you exposed it? Did you expect these flowers to be white/would they be near-white in a normal bromide print, or are you happy with the light blue?

The dried sensitizer was light green, because i took 2 small pieces of cot 320 paper to test, i did not prewash them to see what happens. Next step is to prewash the paper, ander after lighting wash with hydrogloric to see the final result.

For now i am waiting on my chemical order....

 

[Davec101]

Thanks guys for doing the research, i am waiting for some hydrochloric acid, seems quite hard to order in the u.k.

At the moment i am still using fabriano artistico without the pre acid bath and getting a lot better results now if i immidiately expose it under uv light once the sensitiser is dry, around 3-4 mins. The sensitiser remians yellowey green. This seems to give me the highlights and shadow tones that i like. Will post an example later once i have scanned them in.

However at the moment i am also having the problem inconsitant areas of the image being out of focus, i pressume this is because of the sensistised paper is curling slightly and not getting the perfect contact with the negative. I make sure the image is very tight in the contact frame but am still having this problem. I again presume a way around this problem would be that if i have the hydro acid pre wash and then add the sensitiser, let it dry fully and then flatten it, this will solve the problem, but is rather long winded.

 

[Lukas Werth]

Thanks guys for doing the research, i am waiting for some hydrochloric acid, seems quite hard to order in the u.k.

I am sorry I have not checked in for a while.
To get HCL I just walk over the road, and get it in a hardware store. Should not be too difficult in the UK either; have you tried some common drugstores?

As for the paper, try a sort which curls less; a heavier quality maybe?

 

[Willie Jan]

i found it in a paint shop, and a shop where they sell tools and materials for houses.