I’ve been having trouble getting a good even color in my latest woodblock print and I have been trying to figure out why this is happening. As far as I can tell these are the variables that can affect the evenness of the color:
Baren – pressure, quality of baren
Pigment – some colors are naturally grainy (e.g. French Ultramarine Blue)
Nori/Water/Pigment – ratio
Wood – type, grain
Paper – differences in texture, sizing, and fiber content
Admittedly I am working with an inexpensive baren and will need to upgrade there. A better quality baren is sure to improve the evenness in tone. As for the pigment, I have used mineral violet in many watercolor paintings and have not found it grainy. Yellow ochre pigment is a bit grainy, but seems to be less noticeable (probably because is it a lighter color). Likewise, I am using a similar nori/water/pigment ratio as I did in lonely dog which did not produce this blotchy effect. I have also tried using more or less water/pigment/nori with little difference. As for wood, I am using shina which is smooth with tight, even grain. So paper seems to be the one factor that could be causing the blotchiness.
Here are three types of paper all printed in the same way. The mineral violet seems to be a bit less blotchy on the nishinochi paper. Nishinochi is made with 90% Northern kozo and 10% acid free pulp. The gampi is made with 100% gampi and the Exhizen Koso is 100% kozo. All of these paper look and feel very different from one another.
After I get a better baren I will try this experiment again and see if the paper still makes such a difference.