Thursday, August 11, 2016

Light-fast Testing Shinhan Watercolors (PWC)

      I usually have watercolor paper trimmings lying around as leftover from making a sketchbook. Just for fun, I've decided to swatch my favorite color from Shinhan and do a light-fast test. I did this by painting a gradient wash on a strip of paper about 5" x 1.5"  then cut it lengthwise so that I have an identical strip. I then taped one strip on my window and kept the other one inside an envelope. A month has passed by and comparing the 2 strips, I was surprised that there is no difference. No fading, no discoloration. I'm aware that true light-fast testing takes a minimum of at least a year, but just the same I expected some result since my window is in direct sunlight from 11am to about 5pm.
     This encouraged me to do a test on all the Shinhan paints that I have so I made a swatch as seen below :

 Here is the swatch before it was cut and exposed. 7.5" x  5.5" 300g Arches CP

Here is the list of the paints I've used : 

Permanent Yellow Deep(PY83)
Permanent Magenta(PV19) 
Permanent Rose(PV19)
Permanent Red(PR209)
Burnt Sienna(PR101)
Ultramarine Deep(PB29)
Cobalt Blue Hue(PB29)
Raw Sienna(PR101)
Lemon Yellow(PY81)
Davy's Gray(PBk31,PG17, PW6 )
Neutral Tint (Pb66, Pbk11)

      Notice that some colors like Permanent Magenta(PV19) and Permanent Rose(PV19) have the same CI (Color Index number). This happens even with other brands and it is not a bad thing. Usually pigments may have other trace amounts of compounds/or impurities like silica magnesium, aluminum etc. and may bias towards certain hue during the manufacturing process. Another pigment that has this quality PR101 which is a synthetic iron oxide. 
     There is also PG7 which is marketed as Viridian but is actually  Phthalocyanine Green which is really known to be light-fast(Though true Viridian PG18 is known to be light-fast as well ). This is when learning a pigments CI number pays off :).

Half of the swatches to be exposed are pasted into an illustration board with the binder clip to make it stand.

Unless it is cloudy or raining, this is how the swatch was was exposed. The photo was taken at about 1pm.
I came to check after a week of exposure(April 28 - May 10). The swatches on the left are the ones not exposed. No noticeable difference. Boring :)

After a month (June 10)

July 10

Finally August 10
     I would have to admit that my testing was a sloppy job, I did not make decent gradient in all of the swatches. It was just supposed to be a quick and dirty test. Yet, the results are quite surprising. Unfortunately, these are the only colors from Shinhan that I have, so my test results are limited to these colors. I will continue to leave this on my window on in the next few months, and see if something comes up. 
     If this test proves to be successful, it is good news for all of us since we have an affordable professional quality grade paints as alternative to better known brands that performs just the same.
     If you are interested in doing your own light-fast testing, you may want to check out Wetcanvas and Handprint for a more detailed procedure.


  1. Ay ang galing! Thank you for posting this. I'm better informed. :-) Kaya ba importante ang fixatif dahil sa ganitong effect on the colors?

    1. Hi Glenda! Thanks for dropping by. I haven't used a fixative, but from most that I have read, framing a watercolor piece behind a glass is sufficient. The main concern is to protect the painting from UV light since it is the main cause of the breakdown of color that makes it fade. Making sure that the color you use is lightfast is just another layer of insurance. Of course it doesn't stop there, using archival paper, storage,( temperature and humidity) is also a factor. Using fixative might require some further reading, though I've read somewhere that there are fixatives that also offers protection from UV light.I hope I have addressed your concern.