EAC

Disfiguring stains were removed from the paper.

A discolored and water-stained etching before and after treatment.

To an unsuspecting observer this artwork may look like a watercolor; but a paper conservator would ask: "what type of printing have we got here?" One has to look closer, but all the clues point to collotype printing. Our initial clues are a lack of a plate mark and an edition number indicating that we have a print, not a watercolor. Under magnification a pattern characteristic of collotype printing emerges. Knowing that the clients' grandmother bought it in Paris in 1930s is the final clue! 🙂
Collotype is a dichromate-based photographic process invented by Alphonse Poitevin in 1855 to print images in a wide variety of tones without the need for halftone screens. The majority of collotypes were produced between the 1870s and 1920s.

Stain reduction on a chine-collé print can be very risky because of the layered nature of the chine-collé technique. There are before and after treatment photographs included below; 19th c. etching of a landscape.

So first what is chine-collé? Chine-collé roughly translates from French as “chine”= tissue, and “collé” = glue or paste. The word chine is used because the thin paper traditionally used was imported to Europe from China, India and Japan.

It is a special printmaking technique in which paper of a different color or texture is adhered to the heavier, overall paper piece.
The paper, usually in pre-cut shapes, is actually bonded to the heavier support paper of the print in the printmaking process. It is not just glued to the print as a collage element. Chine-collé is sometimes mistakenly used to refer to any type of collage.
But, the over-all effect of collé is that the paper is actually bonded, not just glued, to the print. It can, at times, look like it is embossed.

Self-adhesive tape often leaves sticky residue and for that reasons paper conservators do not like any tapes to be used on the artworks. Below is an example of a sticky tape residue before and after treatment. It does not always work out so well.

Pith "paper" is not paper, even though it is often called "rice paper"; it is a misnomer. Pith behaves differently than paper because it has a different structure. It is more fragile than the thinnest paper, and can be easily crushed and damaged. Traditionally pith sheets were produced in China to be used for painting and decorations (manufacture of artificial flowers for example). Chinese pith paintings became all the rage in 19th c. and were often sold to the visiting westerners. An example of a pith painting and an magnified detail of the white background is shown in the photographs below.