Struggling to get consistent prints with New Cyanotype chemistry

jrhilton

Member
Joined
Nov 5, 2007
Messages
82
Format
Medium Format
I agree with what Patrick says, namely stick with the original process. I never had great success with the new one, but can get great looking prints using the original process. Finding the right paper is key though. I think I have mentioned this in the past on here but the best paper I ever tried (in terms of detail and image quality) was Epson heavyweight matt paper, but struggled to clear unexposed sensitizer - 13 years later the test prints still look great.

I also add a drop of Tween 20 to the mix, and find it helps get a nice even coat.
 
OP
OP

jonmon6691

Member
Joined
Oct 6, 2021
Messages
95
Location
Portland Oregon
Format
4x5 Format
I'm super grateful for all the feedback from everyone, and despite the ups and downs the challenge itself makes this all worthwhile to me.

With regard to adding tween 20, I've seen this come up a few times but no one is specific about how much and in what concentration (perhaps its not critical but I also don't know that either). One drop to the whole 100mL of sensitizer? or a drop to each small batch of sensitizer as I apply it to paper?

On the subject of acidity, I think I'm gonna order a pack of litmus paper strips so I can keep track of that variable. I watched a video from North Light Photography about balancing tween's alkalinity with an acid, seems like thats a theme
 

jnamia

Member
Joined
Apr 13, 2022
Messages
185
Location
local
Format
Multi Format

I haven't used tween, but I agree 100% with what you and Patrick said. The original process is so simple it should be illegal.
 

nmp

Member
Joined
Jan 20, 2005
Messages
2,014
Location
Maryland USA
Format
35mm
Regarding Tween 20: Strictly using surface science, one should not need to use more than a very tiny amount, like less than 0.1% w/v (or so) of the whole liquid volume - based on the concept of CMC at which the surface tension reduction plateaus.


Any more after that simply goes in formation of more/bigger micelles in the bulk of the liquid without any benefit to the surface. There may be some other effects of adding larger amounts. It is significantly more viscous liquid than your typical sensitizer so adding a lot of it will increase the overall viscosity of the sensitizer. It can presumably also act as some form of a binder. What do these do to the print - could be good or bad, so use accordingly.

:Niranjan.
 
Last edited:

Andrew O'Neill

Moderator
Moderator
Joined
Jan 16, 2004
Messages
11,956
Location
Coquitlam,BC Canada
Format
Multi Format
I am seriously thinking of going back to the original Cyanotype formula. I was getting consistent results with it. The new cyanotype is finnicky. I'm givin'er one more go this evening.
 
Cookies are required to use this site. You must accept them to continue using the site. Learn more…