Cyanotype highlight staining help!

Discussion in 'Alternative Processes' started by Markkent91, Feb 22, 2018.

  1. Markkent91

    Markkent91 Member

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    Hello all,

    I have been practicing cyanotypes for the past month or so and have had some great results. Recently however, I have been experiencing a large amount of light blue staining in the highlight areas.I expose using a UV light exposure unit and From my experiments, the average time for some very pleasing deep blues and contrast exists inbetween the 4- 5 minute range .

    When exposing over 5 minutes, I achieve some very deep blues however the this recently has been increasing the staining in the highlights. Of course, If i underexpose, this reduces the staining but does not achieve the wonderful deep blue tones and is further washed out at the washing stage.

    This has only become a major problem recently and as far as I know, I have not changed my method. I do not use acid or chemical washes of any kind: purely washing the prints with running water.
    I use a single coat and leave the cyanoytypes drying usually for an hour or two. The paper I use is just some heavy gsm cartridge paper from my university. Unfortunately I cannot afford more quality papers but this paper has always been very good for cyanotypes in my experience.

    Please see the examples of a few test sheets i did; both exposed at 5 minutes resulting in good dark blues, but too much staining in the white backgrounds. If I reduce the exposure, I lose the tone.

    What can I use to reduce the highlight staining?

    Many thanks for all your replies!

    Mark
     

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  2. jim10219

    jim10219 Member

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    This sounds to me like the ink used on your negatives isn't dense enough for long UV exposures. If you're making your own negatives, try using a different color ink with better UV blocking capabilities. You may have to run some tests to figure out which color blocks UV the best.

    Though my experience with that has been that it makes the middle tones less consistent because my printer doesn't always print smoothly across a single color saturation spread. So I've just learned to live with it and find a happy medium.

    You could also try bleaching the highlights in some borax, washing soda, or TSP. Those should attack the highlights before hitting the shadows. But you'll have to experiment with the correct concentration of chemicals and time of submersion to get the balance right.
     
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    Markkent91

    Markkent91 Member

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    Hi Jim, yes that has crossed my mind. I print my images onto transparency/Acetate paper and normally increase the density via the printer. The printer is a large one - the kind you see in libraries and educational institutions. Having said that, the acetate negatives I have been using over the past four weeks have not had this problem with the highlights.

    I conducted a test whereby I used one of the acetates for my successful cyanotypes a few weeks ago that produced clear highlights. I exposed that along with with another acetate that I have been experiencing problems with recently. Both of them had the highlight staining which would lead me to believe it is not the negatives ( Unless the ink on the acetate from the successful one has deteriorated over the last month which has been stored in the darkroom)

    I am going to mix up some more chemicals next week to see if my problems are with the cyanotype solution. It is rather frustrating as you may imagine.
     
  4. Svenedin

    Svenedin Subscriber

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    I'm not an expert on cyanotypes by any means but I have had some successes with the process. Your prints look very on/off. It's either blue or nothing. Granted cyanotypes have a reduced tonal range compared to a conventional print but yours seem to have a very reduced range. I use Daler Rowney Langton 300 gsm HP watercolour paper which is available in art shops (at least in the UK) and isn't particularly expensive. I coat by drenching the paper in solution (with a little tween added). I expose in the sun. My negatives are printed on Permajet digital transfer film and printed on an Epson inkjet. I did also try negatives on laser printer film using a laser printer and these worked too but not so well.

    Examples here:

    https://www.flickr.com/photos/144059001@N05/36668419284/in/dateposted-public/ (permajet negative, inkjet printer)
    https://www.flickr.com/photos/144059001@N05/31029180746/in/dateposted-public/ (laser printer OHP film, laser printer negative)
     
  5. jim10219

    jim10219 Member

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    Did this problem only start when you increased your exposure times? Because the inks your using may be fine at 4 minutes, but show staining at 5.

    But if it's not the ink, then I'd look to the paper. Some paper stains easier than others. You might try a different paper or try sizing your paper before coating it. I often use PVA for size on alternative processes, but find for certain types of paper, it can make cyanotypes coat unevenly and wash out in blotches unexpectedly. For other types of paper, it works well. Even if you think you are using the same paper, manufacturers will often change how they make their paper and not tell anyone. So one brand may work well for years, and then one day not work well anymore.

    But the first thing you need to do is conduct multiple experiments where you only change one variable at a time until you find the source of the staining. From there, we can figure out what to do about it.
     
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    Markkent91

    Markkent91 Member

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    No, in some of my earlier successful cyanotypes from a month ago I did get a tiny amount of staining in their highlights but it was so minor that when washed, the water would clear away all staining leaving clear white.

    Here is another example; the better one without staining was from last week and exposed around 5 minutes. Unfortunately, the silhouettes of the people in the bottom right corner were not as visible as I would of liked. I therefore used photoshop to alter the contrast in that specific area around the people so they would be more visible and printed this off into another negative (laser printer if I did not mention this) .

    This week, I exposed again at the 5 minute mark with the new negative but resulted in heavy staining. Could it be the UV exposure unit is not exposing correctly perhaps?

    Additonally, the cyanotypes that have been suffering from this problem I have noticed are overall, a much lighter blue even when exposed at the same time as previous.Furthermore, I have noticed the last few coated and dry papers look far more inconsistent and blotchy with their coating despite my coating technique not changing. if you look around the edges, especially at the bottom of the "test 2", you will notice this chemical inconsistences.

    In any case, I shall conduct some further tests and report back. Thank you for the suggestions and advice.
     

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  7. mitorn

    mitorn Member

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    I had a similar problem, the pigment dissolved from the darker areas into the wash water and settled in the lighter areas during washing. I stopped using running water and instead used trays. Worked for me.

    Anyway I have a few questions:

    What paper and what sensitizer do you use?

    If you store the coated paper a few days in a dry and dark place is it still yellow or already green or blue? I find it unlikely but it could be chemical fogging due to impurities.

    In your printing session is every picture affected the same way or only the later ones? If you are using a fluorescent lamp as source and it is cold in your printing room the first picture can be underexposed, because the luminous flux of the lamp will increase with temperature and as the lamp heats up the flux increases and therefore the necessary printing time will decrease for the later ones. If you always use the printing time of the first picture the others will therefore be a littlebit overexposed.

    By the way, it takes time to reach the final density. The picture oxidates after “development”… So you might try to expose for a minimal shorter time just to omit the fog and keep your desiered final density. You can use a diluted hydrogen peroxide bath before the final wash to speed up oxidation, which will allow you a better judgment over its final density.

    -martin-
     
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    Markkent91

    Markkent91 Member

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    The paper I use is just heavy weight cartridge paper (220gsm) so nothing really expensive. I use the traditional cyanotype recipe that is 10g of potassium ferricyanide and 25g of ammonium ferric citrate.
    I have read that increasing the amount of these chemicals to stock increases the density of blue is that correct? So would 20g of Potassium ferricyanide to 35g of ammonium ferric citrate offer a greater blue tone and contrast?

    I normally use the coated paper on the same day after two hours of drying and majority of the time it is yellow. However, my last test I left the coated paper drying from the morning of that day to the morning of the next day sealed in a light tight bag ( the same that darkroom photographic paper is kept in). When I opened the bag, the paper was a little greener but more observable, the edges all around the paper ( about 3 inches in) were fogged/blotchy; this was just around the edges of the paper as though someone has been blotting the edges with a cloth. I still exposed the coated paper which was my "test 2" ( see image above) but one can observe these issues around the edges.

    That is an interesting point regarding the lamp. Coincidently, I had wondered whether the first minute or so of exposure is less powerful than the remaining time due to the machine warming up and thus impacting the final tone and density.

    Yes I always leave them to dry in the dark. Where my earlier successfull examples would transform into a deeper tone fairly quickly, my recent troublesome ones do not transform as deep when left in the dark to dry.

    Below are a couple I produced 3/4 weeks ago. As you may observe, the contrast and highlights are very different to that of my recent ones.
     

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  9. Svenedin

    Svenedin Subscriber

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    I use the traditional recipe. I leave my paper to dry in pitch dark. The paper is green before exposure. I watch the exposure (in sunlight) and can see it start to become yellow in the light. By the time I am happy with the exposure some parts are turning a light blue.

    These are different negatives but do follow the stages of the process:
     

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    Last edited: Feb 24, 2018
  10. mitorn

    mitorn Member

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    I have never tried it, it could work but also it could crystallize on the paper.

    Sounds to me like chemical fogged. Anyway I have found an algorithm to debug fogged highlights in Mike Wares Cyanomicon2 (http://www.mikeware.co.uk/mikeware/downloads.html) on page 221. You might want to have a look upon it.

    The sweet spot for fluorescent lamps is usually somewhere between 25°C and 40°C. Depending on the ambient temperature they will heat up quickly or not at all in 5 minutes.

    By the way, a possible other cause is the washing water. If you are using tap water, it is possible that the company/local authority changed the way they treat it. I don’t know how chlorine would affect it, the tap water here is just filtered spring water.
     
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