If a vintage poster is in bad condition, but it is rare and sought after, it could be worth to restore it. In case of noticeable yellowing or discoloration, bleaching could be necessary. Ask paper conservation professionals to do this, never try it by yourself! They work for museums, archives and collectors, too.

First: Possibly existing old tapes must be removed by careful use of chemicals. The next step is washing the poster.

Washing allows the fibers to swell open, cleans the surface and neutralizes acidity. In case of being rolled for a long time, the paper can relax now and gets back its original size.

There are many possibilities of paper problems which need professional treatment. Bleaching is only one one of them, please ask  restoration studios for help. Be careful, bleaching is definitely NOT HARMLESS! It is a very stressful process to any paper and one that must only be done when all other options are not going to solve the issues.

Be careful: Some kinds of bleaches destroy the bonds between the paper fibers meaning that the paper loses all of its wet strength, it has the consistency of toilet paper when wet. The yellowing process of the paper could be accelerated and worsened. So the effect of bleaching a poster could be that the paper loses all strength and will yellow/brown much more severely after a while.

In case of significant yellowed paper, metal caused dots or foxing (brown dots caused by fungus), it could be necessary to bleach the poster. Bleaching could be done by many different procedures, ask an experienced restoration professional for the best choice to solve your problem. The pictures show partial bleaching at the margins with a brush and in a bath of potassium permanganate.

Linen backing is the most common archival poster conservation method, accepted and preferred by dealers, galleries and many collectors worldwide. It provides stability to the poster, it smoothes and flattens out waves and wrinkles and makes creases and folds invisible or less noticeable. A linen backed poster can be removed by a restorer from the canvas without any damage.

Linen backing usually works like this:
A large piece of artist grade 100% cotton canvas (“linen”) is tacked onto a solid wooden frame ‘stretcher’. It has to be pulled very tight so that there are no ripples and the tension is evenly distributed. Good restorers prefer tightly woven cotton canvas that does not have a strong or noticeable texture which would show through on the finished poster. Next step is mounting a large piece of acid free archival quality paper on the streched canvas. The only glue any linen backer should use, is water based pure wheat starch glue. It is totally reversible and acid free. Best quality is made in Japan, it is highly refined and all natural.

A poster with traces of aging should have been washed, cleaned and (if absolutely necessary) bleached before mounting on the paper backed canvas. The poster has to dry a bit before linen backing. It is recommended to press the poster against cotton blotter and paraprint/hollytex which absorbs the acidic material and dirt of the washing process.

Mounting the dry (or little moist) poster on the prepared canvas with wheat starch must be done very carefully. It is necessary to remove any remaining creases or bubbles by a really soft bristled brush and a rubber roller. This needs a lot of experience, because there is a risk to damage to the surface of the moist poster or it‘s colours.

Also called "Japanese Tissue Lining". This is a common archival poster conservation method too. The poster is de-acidified and mounted with wheat paste onto a piece of very thin high quality acid free Japanese "Kozo" paper. Kozo paper is made from the inner bark of mulberry trees.

Paper backing has the same advantages like linen backing, except the stability. But on the other hand it still feels like original paper. In case of framing you don’t need a mat to cover the canvas.

This poster conservation method is recommended for posters in very good condition only. A starch backed poster has been flattened, cleaned and de-acidified, but fold lines will usually still be noticeable. It’s not mounted to anything, it feels like the original. The backing is made by use of powdered wheat starch and a small amount of buffer (calcium carbonate) mixed with pure water.

Some collectors protect their posters from moisture and dirt by the method of sealing them in plastic film.

It could be a problem for the printing color, if the plastic is not free of solvents or plasticizers. And some types of mold grow better without fresh air.

The last step is restoration of missing or damaged details in the image. Missing areas are replaced by use of original vintage paper similar to the original.

Scratches or missing details in the image are retouched. Professionals will use methyl cellulose to protect the original poster from all colors which are applied for restoring purpose.

A lot of vintage posters have been destroyed by sunlight. Exposure to UV light accelerates the crystallizing of paper’s cellulose chains. It causes premature stiffness, brittleness and discoloration. It will also cause inks, dyes and paints to fade and discolor.

If posters should be displayed, please use proper acid free mats (passepartouts). Framing with 99% UV filtering plexi or protection glass is the only way to protect a poster and preserve its value for many years. Never place framed posters in direct sunlight!

The best thing to do is to change displayed posters twice a year.

I prefer professional frames manufactured by HALBE. These frames are easy to use, a magnetic mechanism allows to change the artwork very comfortable.

HALBE frames are recommended by museums worldwide.