RE: 1st & 2nd Cyanotype

Gu, does the dried emulsion stay a greenish yellow or do you see any signs
of blue? The second prints looks like a) Fogged (either chemical or due to
UV light hitting the paper while it dries) b) Developed in very acidic
water. If you see blue in unexposed paper you should either change the paper
(since it's not so good for new cyanotype) or add a drop of 40% citric acid
per ml of coating solution to prevent chemical fogging (you should
recalibrate in that case since adding citric acid lowers contrast of the
emulsion). If you see blue in wash water it may show you used too much
emulsion and / or your wash water is too acidic.
 
To prevent chemical contamination, wash well the brush between coatings (as
soon as coating finishes) + rinse in distilled water.
 
As Camden says, also try hake or good quality watercolor wash brushes
(Richeson or Da Vinci brushes are good - you won't believe the
difference)... Since I see you mask the image borders, you can also use
glass rods for coating (very even results).
 
I dry cyanotype coated papers until they're bone dry (min. 2 + 30 minutes
with cold air stream if I'm in a rush, usually 1h). Working environment RH
is around 40 - 60...
 
Maybe you use too much emulsion per coating area (it's hard to control this
with foam brushes). With good watercolor papers and when coating with glass
rod or moist magic brush, 0.2ml coating solution per 10 inch square is quite
sufficient, more than this will usually cause grainness, mottling, paper
fiber abrasion IME (and will take longer to dry)...
 
Nice first try BTW!
Keep going,
Loris.

  _____

From: G Guhan Gunaratnam [mailto:guruguhan@hotmail.com]
Sent: 21 Temmuz 2006 Cuma 20:43
To: alt-photo-process-l@usask.ca
Subject: 1st & 2nd Cyanotype

Hello,

I made a couple cyanotypes (Ware type II) last night and I was hoping I
could get some feedback. I followed the instructions on Mike Ware's site.
They are only first attempts, I'm pretty happy with the results. Both were
done with the same drop count, exposure and clearing time, only the paper is
different.

* unknown papers (I was given some old, dirty paper from a pro silver
printer who dabbled with Pt/Pd at one point - when I first got it I first
washed the paper and was able to remove most of the dust/dirt that had
settled on it, I believe the first paper could be Strathmore Bristol, the
second I'm not sure)

* drops = 12

* foam brush

* after sensitizing paper sat for 2mins, then used hair dryer (cool
setting)

* approx 15mins exposure (under a nuArc)

* humidity was uncontrolled (paper not pre-humidified, room was on the
dry side)

* room temp was 23C

* used Toronto tap water to clear (when I used pH strips to test I
read it at 6-6.5, but I'm starting to think that either I'm reading the
strips incorrectly, or something else is wrong with them)

* 3% hydrogen peroxide to bring out image immediately

* more tap water to clear peroxide

The image can be found here (sorry, I don't have a scanner so I just shot
this with my digital camera):

http://www.gunaratnam.ca/_MG_4304.jpg

Like I said, this was a first shot at it. I know I should increase the
humidity in both cases and use a slightly acidic clearing bath - but I just
wanted to see the results like this. I believe the increased humidity will
help in applying the sensitizer evenly (a problem in both). The print on
the first paper (could be Strathmore bristol) has some kind of
mottling/speckling (easiest to see in the sensitized, but unexposed areas of
the top print). After doing the first print I thought it might be because I
didn't filter the sensitzer enough when I made it (though when making it I
filtered it twice through a medium grade filter paper) but the effect is not
there in the second print - leading me to believe its the paper.

Seeing how the second print came out, my first thought was - too long an
exposure (for this paper). Is that the correct conclusion, or should I be
thinking, poor clearing or something else? What can you say about the two
papers? (eg. "the second one is ___adjective___", "the first one shows more
___adjective___ than the second).

I'll be using the second mystery paper again for the next test. Will
prehumidfy the paper, do a shorter exposure and try to properly clear it
(maybe put into a weak citric acid bath first then clear with the toronto
tap water).

As always your thoughts are greatly appreciated. Thanks for reading this
lengthy post

Regards,
Gu
Received on 07/21/06-12:46:42 PM Z