Photo purchased from … www.depositphotos.com
What is the difference? How can you make sure that the old print you found at a thrift store is not from a huge print run of offset lithographic posters?
First of all, some backstory. I have a fine arts background that predates my 45 years in the commercial printing and publications field. So, early on, when I saw the artistry in the custom printing field, I became interested in the similarities and differences between fine arts lithography and offset lithography. I started going to estate sales and art auctions, and even now my fiancee and I always check out the art print section of our favorite thrift store.
The Lithographic Process in General
Here’s a recap of lithography in general. Water and oil do not mix. Therefore, if you first mark a flat printing plate with a greasy substance that will attract commercial printing ink to the image areas, and then dampen the plate with water, you can lay a sheet of paper on the plate (in either a commercial or fine art press) and apply pressure to the back of the paper, such that the ink will be transferred onto the paper in exactly the right places. The water will keep the ink away from the non-image areas. The image can be quite detailed and still remain separate from the non-image areas. In addition, keep in mind that the printing plate is absolutely flat (planographic). Only chemistry is keeping the water and ink apart.
(This is in contrast to relief printing, like letterpress, in which the image areas are raised from the surface of the plate. It is also in contrast to intaglio printing, like engraving, in which the image areas are recessed, or sunken below the surface of the plate.)
Traditional Lithography
As is the case with many inventions, traditional lithography was based on a happy accident in 1796. Alois Senefelder (according to my research) found that if he printed his literary works (scripts, actually) on limestone using a greasy crayon, he could roll ink onto the limestone, apply paper to the limestone (plate), and make multiple copies using pressure to transfer the ink from the stone to the paper. The printing ink would adhere only to the marks he had made with the greasy crayon.
Over the ensuing years, metal plates were used in the same way (aluminum or zinc) because they were easier to transport than blocks of limestone.
As lithography matured, the following processes were added. The printer rubbed a layer of powdered rosin onto the already marked (greasy) image area and then a layer of talc. Then the printer would brush on a layer of gum arabic (alone or with a mild acid). All of this “fixed” the already-drawn image area and allowed the non-image areas to absorb water (which would then repel the ink).
Then the drawing on the plate was washed down with lithotine (which left only a light image of the initial drawing), and asphaltum was rubbed into the entire image. At this point the plate was ready for printing.
And to go back to the general description of lithography, the plate was dampened with water, ink was applied (sticking only to the image area), moist printing paper was laid over the plate (along with a board that was used as padding, and the firm pressure of the printing press transferred the image from the plate to the paper. This had to be done an additional time for every additional color of ink used. (Things started out in black and white, and then printers began to incorporate color as this process was further developed in the 19th and 20th centuries.)
Essentially, this is the process that’s still done today.
Offset Lithography
When you strip out all of the computerized and mechanized elements of offset lithography (the comparable process used for commercial printing), you have the same ink/water separation, flat printing plate—pretty much the same process as original, traditional lithography. It is an art as well as a science.
However, here are some differences:
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- Offset lithography, as the name implies, involves offsetting the printed image. That is, the commercial printing plate first deposits the image on a rubber (i.e., compressible) blanket. From here the image is transferred to the press sheet. (That is, in offset lithography, the plate never comes in direct contact with the paper.) In contrast, in traditional lithography, the plate does come in direct contact with the paper.
- Offset presses can print one of the four transparent process colors (cyan, magenta, yellow, and black) or a PMS color—or not print it—but only as a solid color (without gradation). There is no “in-between.” It is not possible to create lighter or darker tones of a hue (tints and shades): that is, no lighter or darker cyan. Because of this limitation, as offset lithography developed, the concept of the halftone was created. Images were converted from gradations of continuous tones into halftone dot patterns. Larger dots in the equally spaced halftone grid gave the impression of darker tones. Smaller dots gave the impression of lighter tones. When halftone dot screens for the individual colors were tilted relative to each other (prior to platemaking), printers could achieve the visual approximation of tints, shades, and even full color when printing these overlaid, transparent process inks.
So What Do You Look for in a Print
Essentially, what makes an original fine art litho valuable is twofold. First, the artist did the handwork of preparing and inking the stone or aluminum plate, and participated directly in all other aspects of print creation. Even though there’s more than one original (unlike an oil painting), you know the artist made all of the design decisions.
Because of this, you will see the artist’s signature on the lithograph as well as the print number (let’s say 1/500, which means the first litho taken from a press run of 500 copies). If you find one that has an “AP” noted, that means “artist’s proof.”
Second, and very much related to the “1/500” notation above, is that there are only a limited number of prints. (Scarcity of good things makes them valuable.)
An offset printed poster is neither rare nor (usually) hand-signed by the artist. Hence, it is far less valuable than a true art lithograph.
Here’s what to look for to distinguish an art litho from an offset litho.
If you look at a fine art lithograph under a printer’s loupe (mine is 12-power), you will see a light and random dot pattern that indicates the texture or tooth of the rough press sheet. The key, however, is that the dots are random. Also, the different colors of ink overlap (as in offset lithography) and the films of ink are thick (unlike offset lithography).
But here’s the real key, and here’s why you might want to keep a loupe with you when you’re trolling the estate sales. If your print is an offset lithograph, the dot pattern (which was irregular in the traditional litho and was due to the roughness of the paper) is perfectly regular in the offset lithograph. In fact, in the color photos, you’ll also see the “rosettes” (they look like flowers) that are due to the halftone dot screens’ having been tilted slightly in relation to one another.
If you see the rosettes (for full color) or halftone dots (for a tint of an individual color), you may also notice that the offset printed ink layer is very thin and transparent.
Also, you probably won’t see an artist’s signature, and if you do, it was probably already on the art when the designer took the photograph to then print as a poster.
So here’s the key. A print at the thrift store with a halftone dot pattern is probably one of hundreds or thousands of similar copies, which were never touched by the artist. They were just reproduced using photography and commercial printing. Buy them only if you like the way they look, because they essentially have no intrinsic investment value.
In contrast, a print that you find in a thrift store—and they are there to be found—that has a random dot pattern, thicker inks, and the artist’s signature will be worth significantly more than the $3 to $10 you may have paid for it, and far more than the poster version produced via offset lithography.
But even more importantly, it’s kind of cool to find an original, signed piece at an estate sale. Since you know how it was made, and since you know how integral the artist was in its creation, you have far more of a bond with the artist than you do with a poster.
So keep your eyes open at the thrift store. And bring a loupe.
This entry was posted
on Tuesday, August 17th, 2021 at 4:32 pm and is filed under Fine Art Printing.
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