Cyanotype touble

[kevin klein]

How long does it take for most of you to expose a cyanotype in the sun? mine have been taking over an hour or two. They used to take only a little longer than an albumen print. Does cold weather have anything to do with it?
I might just get rid of the chemicals and buy new ones.

 

[BrianShaw]

I always noticed a difference between winter sun and summer sun (and minor differences based on time of day) more than temperature differences. But the exposure difference should not be a matter of minutes versus hours.

 

[Jim Noel]

Either your negatives are over-exposed and over-developed or something is amiss with your chemistry. Yes,cold weather can have an influence because all, or at least most, chemical activity slows as the temperature gets below a given point, but I wouldn't expect it to be this great. Do you buy your chemistry as a kit, or mix your own? I suggest mixing your own fro raw chemicals if you are not doing so. Immensely cheaper over the long term and you have control of what is in them. I keep my cyanotype chemicals separate and only mix the "A" and "B" to together prior to printing. I have never had a batch go bad.

 

[BrianShaw]

... and which cyanotype formula are you using - traditional or new?

 

[Vaughn]

Papers make a difference, too. Same paper?

 

[BrianShaw]

Papers make a difference, too. Same paper?

Not intending to derail the original question/thread, but seeking to clarify -- I know there are differences between paper and sizing, but would it result in exposure differences of that magnitude? I have limited experience in that aspect due to paper/sizing standardization.

 

[Vaughn]

A heavily alkaline sized paper might cause problems when teamed up with a dense negative, etc. I think the OP needs to determine all the various variables that may have changed between printing sessions. Time of day, time of year, any differences in negative density, paper changes, water changes (might be season differences in alkalinity of the water supply), etc etc etc.

Also the difference between an hour exposure and a two hour exposure is only one stop...not much, really. We were not told how long an albumin print took to expose properly. If it was 30 minutes, then we are only talking one to two stops difference.

 

[Gadfly_71]

Issues to consider:

- Same negative, same film? Some films have a coating that reduces the amount of UV that reaches the paper.
- Buffering agents in the paper?
- Have you accounted for dry down? Cyanotypes darken considerably as they dry. You can simulate (to a degree) what the image will look like when dry by adding a cap full(ish) of hydrogen peroxide to your rinse out. The temporary oxidation should give you a reasonable guestimate.
- Bad chemistry (either due to age or cross contamination)

Good luck!

 

[cliveh]

20 minutes in direct sunlight.

 

[hermit]

Unless your negative is extremely dense -- as in black, that is way too long. Junk the chemicals! Doing some every day when there is Sun. NONE over 15 to 18 min.

 

[mossbloom]

Yep: chem problem

I can't add much to what's been said. This looks like a chemistry problem. If you're using the original formula, you shouldn't be much over 20 minutes. Mike's new formula is a whole lot faster.

 

[kevin klein]

Thanks for all the input. I am using the traditional formula, the chems are over 10 years old, and it is cold outside. I thaught too the paper might have something to do with it, using coldpress water color paper. I also used the strathmore 300 series scetch paper with the same results.

What is Mike's new formula?

 

[cliveh]

the chems are over 10 years old

Cyanotype coated paper does not keep and I should imagine this is your problem.

 

[BrianShaw]

...

What is Mike's new formula?

http://www.mikeware.co.uk/mikeware/New_Cyanotype_Process.html