Designates a poster in virtually mint condition and because posters are delicate and printed on thin paper, very few survived the years in this state. I don't use this term very often, as I try to be conservative in my grading.
Designates a poster in excellent condition overall, with fine eye appeal and collectability. The colors will be extremely fresh, and the paper as well. There may be evidence of a very few short tears, and perhaps light evidence of folds. There might be a very tiny bit of margin repair, but this would be described in the listing on this website. This level of condition is extremely satisfactory for almost all collectors and I strive to have the vast majority of my inventory in this quality range. Posters in A- condition will certainly find widespread acceptance among discerning collectors.
Designates a poster in very good condition. There may be the tiniest fading or spotting, but in most cases the colors will be as fresh as an A-. If there is very minor restoration, it is not immediately apparent, unless searched for closely. There may be a number of tears, and only a tiny amount of paper loss. B+ posters are also highly collectable, especially if the rarer issues.
Designates a poster in decent condition. There may be slight fading or faint stain. If there is minor restoration, it may affect a few square inches of the poster at most (ie. less than 2% of the original poster). There may be a few longer tears, and only a small amount of paper loss. Significant wrinkling or harsh folding would also put the condition of a poster at this level. Even still, a B condition poster would look attractive and impressive from a short distance away, the flaws would be only noticable at close inspection.
Designates a poster in fair condition and moderate fading or staining may be seen. Restoration and folds may be quite pronounced, there may be some flaking of paper or minor paper loss.
The accepted process of poster conservation utilizes archival rice paste to lay the poster on a thin sheet of acidfree paper which itself is pasted on light cotton canvas. This is termed "linen mounting" though cotton has been the preferred medium for many years. Linen mounted posters are very flat and well protected against puncture or tears, also any tears or wrinkles that existed before mounting may become virtually invisible. The linen mounting also provides a base for any restoration of damaged or missing areas. This conservation process is fully reversible if it is desired to remove the poster. Within the poster collecting community, linen mounted posters are typically more desired than unmounted posters. The process requires considerable expertiese and there are a very few specialists in this form of conservation.