Making a cyanotype darker?

[athanasius80]

I finally got a source for Arches Platine and compared it to Arches hot press watercolor as my control. The Platine seems to consistantly make a lighter blue than the watercolor paper. I like Platine more and would like to switch to it, so does anyone know a way of making a deeper blue cyanotype? Examples are posted.
Thanks!

 

[smieglitz]

I don't know if this would work, but you might try soaking the Platine in a weak citric or oxalic acid solution and then drying it before coating the emulsion on it. The paper might be buffered or too neutral/alkaline to achieve a deep blue.

Also, try using a 2% citric or acetic acid bath as your first bath instead of water, and if you use tap water, be sure to acidify it before placing the prints in it. Cyanotypes like acid environments.

Joe

 

[donbga]

I finally got a source for Arches Platine and compared it to Arches hot press watercolor as my control. The Platine seems to consistantly make a lighter blue than the watercolor paper. I like Platine more and would like to switch to it, so does anyone know a way of making a deeper blue cyanotype? Examples are posted.
Thanks!

You don't say which formula you are using but if you are using the traditional formula (not the New Cyanotype - Ware formula) try using 2 parts A to 1 part B.
Clear (develop) in water with a slug of white vinegar.

Don Bryant

 

[doughowk]

If using Mike Ware's formulae, the directions from Photo Formulary include adding a drop or two of concentrated citric acid to the sensitizer just before coating. You might also try a 2nd coat. I'm using Arches Platine, and get a dark blue/grey hue in the shadows.

 

[nze]

You may double coat the paper and you will get darker tone. and Arches may be need longer exposure than the watercolor paper.

 

[athanasius80]

I'm using the traditional formula. I'll have to try the 2:1 mix tomorrow.

 

[nick mulder]

I use Crane Kid Finish Ecru with the 'new' formula -

run a weakish solution of Hydrogen peroxide over your print near the final wash (i just splash it in randomly until it works, you get used to knowing how much..)

Dmax instantly goes up - On occasion I have the dark blue going an almost black - sometimes the prints will fizz and bubble, very fun

I never had a darker print than with the Kid Finish paper (which reminds me I gotta cook up a new batch of sensitiser and to get some prints off to people who helped me when I was a newbie also) -

Another good pt type paper (COT320) gave me inferior results with cyanotype... Different horses maybe, but i never tried platine

 

[ceh11]

I use strait Hydrogen peroxide on my prints to just darken them a bit. I put in on right after i wash the print (the paper is still wet when i put it on). Once the print dries you can only see a little difference in color.

 

[Loris Medici]

In my knowing using hydrogen peroxide (in whatever way) won't affect the end result. Cyanoype will naturally darken after oxidation with air. Peroxide will just accelerate that phenomenon. Have you made controlled checks? (Comparing two prints of the same image, one left to oxidize naturally for a couple of days and the other oxidized by hydrogen peroxide...)

BTW in my experience 2A+1B traditional formula won't give you a darker print, in fact it's the opposite. The darkest blues obtainable by single coat Cyanotype can be achieved by mixing A at 25%, B at 12% and use these 1A+1B. (Please note that there's a considerable speed penalty doing so.) Acidifying paper and/or wash water will often help indeed, but beware of the fact that when you do that when it's not really necessary you may experience stain.

As a last note, when compatible (read as a paper with no buffer which has good/even absorption) thin papers usually give higher dmax.

Regards,
Loris.

 

[amuderick]

try longer exposure.

BTW, I have been able to achieve nice Dmax, very near neutral blacks, and a nice tonal range using a carbonate bleach and redevelopment with Gallic acid. It is a bit tricky as atmospheric oxidation at the wrong stage will lead to bleeding of the image. I continue to refine the process but it has a lot of potential.

 

[keithwms]

First of all ask yourself what the maximum dark tone is possible with your setup/bulb etc... simply expose a piece of solution-covered paper without a negative or glass or plastic between. When you develop that test piece in water and peroxide you will see what the maximum tone is. Compare to the darkest tones you're getting through a neg. You may then discover that the darkest tone that you're getting (through the clearest portion of your neg) is still not getting where it could. If that is the case and longer exposure doesn't help, then you may have to consider the spectrum of your light source.

Again, when you do this test, you should have *nothing* between the bulb and the coated paper... no plastic, no glass, no nothin'! The reason is that some glasses and some plastics will cut off the deeper part of the UV spectrum. Then you'd need to dose the clear portions much longer than you want in order to have good tones in the other portions. If that's the case then you will have to think about relative exposures and whether your neg has the right density etc. A step wedge is not a bad idea if you are wiling to take the time to figure out the best possible tone curve.

Double coating does indeed give slightly darker tones, and then there is post-varnishing....

 

[Loris Medici]

Amuderick, what you do is practically converting the cyanotype image to one made with iron-gall ink, the resulting compound is the same/very similar... The problem is that iron-gall ink eats the paper in the long run, so beware if you value longevity...

 

[Vaughn]

To intensify the image, I have poured a dilute solution of Potassium dichromate over the print -- it really snaps it up. I pour it over the print while it is in an empty tray, then pour it back into the bottle.

Works like magic, but I don't do many cyanotypes and dislike using dichromates except for when I have to.

Vaughn

 

[Loris Medici]

Vaughn, isn't that practically the same thing as using a hydrogen peroxide bath? Both dichromate and peroxide are strong oxidizers... Nitric acid for instance, another oxidizer will do the job too if one wants to use even more exotic compounds.

Regards,
Loris.

 

[Davec101]

I finally got a source for Arches Platine and compared it to Arches hot press watercolor as my control. The Platine seems to consistantly make a lighter blue than the watercolor paper. I like Platine more and would like to switch to it, so does anyone know a way of making a deeper blue cyanotype? Examples are posted.
Thanks!

If your using the ware cyanotype sensitiser, to obtain darker results, after exposure place in a bath of citric acid, 30g per litre and agitate for a minute or so and then rinse with water as you normally would.

 

[2F/2F]

They look a bit underexposed. Have you tried baking a plain piece of paper out in the sun, and then developing it to see the darkest blue that you can get?

If you can get a nice, dark blue doing this, but when printing through a negative, can't get a deep blue without also bringing down the whites, the neg you are using is too low in contrast.

I add a splash of hydrogen peroxide after development to speed the oxidization process that will eventually darken the print over time. This does not actually make it any darker than it would get eventually; just makes it happen immediately.

IME, adding Kodak Indicator Stop Bath to the development bath lowers the contrast quite notably. It takes very small amounts to very finely lower contrast.

 

[Vaughn]

Vaughn, isn't that practically the same thing as using a hydrogen peroxide bath? Both dichromate and peroxide are strong oxidizers... Nitric acid for instance, another oxidizer will do the job too if one wants to use even more exotic compounds.

Regards,
Loris.

I am not sure. Does Mike Ware put a dichromate into his "new" formula as an oxidizer? or does it serve some other purpose? The effect of the dichromate is instanteous and extreme. I have never used the peroxide to see if the results were similar.

Vaughn

 

[Loris Medici]

Hi Vaughn,

In my knowing the minute amnt. of "optional" dicromate in Mike Ware's formula is for preservation (provides longer storage times before sensitizer gets bad), not extra density. Also as an additional benefit, dichromate additive slightly increases the emulsion's contrast for better compatibility with "normal" negative densities. (In this context normal defines a density range closer to traditional cyanotype requirements.) Without the dichromate you'll need a negative DR close to log 2.0 (almost) with New Cyanotype - which is considerably higher than what traditional cyanotype formula needs.

You can try peroxide easily, just get the usual 3% drugstore version (which probably you already have at home) and add 5-10ml of this into 1000ml of "final" wash water. Agitate about 30-40 seconds (that's about where you don't see any change anymore), then do a final rinse in plain water and that's it.

Regards,
Loris.

 

[Vaughn]

Thanks Loris,

The next time I make traditional cyanotypes, I'll cut one up into thirds after the water/development bath and do a little test with dichromate, peroxide, and no post treatment. Then let them dry and check them in a few days. Just out of curiosity. It might be a few months, so no one hold their breaths!LOL!

Vaughn