The basic technology is similar to that of lithographing, but the process is more refined, and the finished printing product is obviously different, mainly in two aspects:
First, the ink color of the Koro version can be divided into layers, that is, the ink is deep and shallow, with grayscale, and the photocopied calligraphy and painting can express the different colors of the original work through the shade of a single color. The ink color of the lithograph has no layer, as long as there is ink, it is all the same black. If you use lithographs to photocopy calligraphy and paintings, the different colors on the original paintings cannot be distinguished, and they are often printed as a ball of thick ink, and it is impossible to distinguish between flowers and leaves; Photocopying calligraphy, you can't see the shade of the ink and the beginning and turn, and the printing effect is not good. Because of this, lithographed albums such as "Wu Youru Mobao" are mostly line drawings to promote strengths and avoid weaknesses. The second is that the Koro version has a regular background color, that is, where there are no words and no patterns in the whole picture, a light ink color will also be printed, which contrasts with the white paper around it, and the printing plate has neat edges. This is because the Kolo version has a strong ability to restore, is good at expressing details, according to the original photographic plate making, the original paper slight discoloration is also printed and restored. Lithographs cannot achieve this ability, and where they do not have words and patterns, they are the true color of the paper, and they cannot see the boundaries of publication.
If you use a Koro plate to print calligraphy and engraved books, it also has a background color in the layout, which contrasts with the surrounding white paper. Therefore, it is relatively easy to distinguish between the Koro plate and the lithograph and the engraved copy.
The picture below is a copy of Yuan Shikai's "Huancun Yixing".
The picture below shows Wu Baochu's handwriting in the lithograph of "Beishan Lou Collection", because the ink color is not layered, the handwriting is mixed with the pattern of the notepaper, and it is unrecognizable.
To identify the Koro version, it is necessary to pay attention to a special case, that is, the problem of "color Koro version".
Colo plates can be printed with color pictures by making a plate for each color, and overprinting layer by layer. Simple, such as printing calligraphy and painting with ink, printing stamps with red plates; Complicated, that is, full-color paintings, need to make multiple plates, after the first color is printed, and then overprint the second and third ...... This method is cost-effective and inefficient, and complex colors can only be achieved through "color contrast", which requires experienced technicians and high skills, and ordinary printing houses cannot print high-quality color colo books. Therefore, during the Republic of China, many books known as "color colo editions" were actually hand-colored after monochrome colo editions were printed. Zheng Zhenduo's "Catalogue of the History of Chinese Printmaking" says: "I saw Di Pingzi reprinting the Three Episodes of Mustard Seed Garden Paintings, using the Koro plate as the background, and the woodblock overprint color on it, or even hand-painted, wandering in embarrassment, all of which were everywhere. ”
Di Pingzi's name is Baoxian, and since the end of the Qing Dynasty, he has opened a bookstore and used Koluo to photocopy calligraphy and paintings. The picture below is a page in the Koro edition of Yun Nantian Sketchbook by Youzheng Bookstore, the background color is Koluo print, the color is hand-filled, the pigment used in the stamen is semi-fluid, and it is raised on the paper after drying, and the seal is made of ink.
There are several ways to identify this counterfeit "color colog" version:
One is to see if the color part spills out of the boundary of the image. The color separation of different colors of the Kolo version is done by using optical and chemical principles and modern technical equipment, and the color plates can be well overlapped when overprinted, even if the overprint is not accurate, its contour line can be moved with intention, and it can also be matched. Colors painted with a brush are easy to paint out of bounds, and the edges are neither neat nor matched.
The second is to turn the pages against the light, and you can see the layering of ink and watercolor. The ink used in the Koro version is evenly coated and does not reflect light, while the paint applied by hand is mixed with water, and animal glue is added to it, which will destroy the overall light perception.
Three is still the old way, look at the back. In general, the ink of the Colo print does not penetrate the back of the paper, and the colored area will leak to the back of the paper due to water, forming patches of water stains.
In the tenth year of the Republic of China (1921), the "Fragrant Flower Shadow" published by the Shanghai Aesthetic Education True Appreciation Society, painted 12 flower god statues, and the theme of the flower god and poems. In fact, the full color version is painted on the leaves of the monochrome Koro print, while the text part of the title is lithographed in order to save costs. This book is a combination of lithographs, cologs, and hand-depictions, and can be used to identify the various methods we mentioned earlier.
The picture below shows the lithographed text, which shows that there is no background color in the layout, only the contrast between the ink color and the paper color:
Below is a drawing of a Koro engraving with a background color in the margin, which contrasts with the paper on the outside of the plate. There is gray in the frame. The colors are hand-painted. You can see the colored water stains from the back of the paper.
Excerpted from Identification and Protection of Ancient Books, Peking University Press