I'll be honest--photogravure is a challenging, time consuming, multi-step technique prone to many unique challenges. Factors such as humidity can make or break the success of coming out the other end of the process with a satisfactory plate, and the chances of one of many steps going slightly awry can result in less than stellar results for even the experienced.
So why bother? Because when it works (and despite everything, it can work) there's nothing that can match it. There is a reason photogravure has persisted beyond it's early beginnings in the development of modern photography.
Paul Strand, Camera Work XLIX/L, 1917
There is an almost indescribable quality to the richness and tonal subtleties of photographic images printed using the photogravure technique. One gets a palpable sense of magic that early innovators of photography must have felt to see how an image can slowly emerge--a feeling of wonder that we are immune to nowadays with the immediacy of the instant digital photo.
What accounts for the high level of image quality is that photogravure is the only photoetching process that is truly continous tone. Above are 2 images of a photograph of Auguste Rodin taken in 1908 by Alvin Langdon Coburn. Left is the original continuous tone where values transition smoothly into one another--a multitude of whites, darks, and grays that can capture the smallest details and nuances of light. At right is the same image, this time in halftone.
Halftone is the most common way mass produced photographs are commercially printed, from newspapers with a coarse, highly visible dot, to magazines and books with their much finer halftone pattern. Put simply, with halftone the entire image is rendered into many small black dots. Grays are created based on how many and how closely these dots are clustered, and relies on the ability of the human eye to "blend" these dots into a simulation of tone. Mechanically this makes the image much easier to mass produce. While superfine halftones can come close to the image quality found in continuous tone, it eliminates the nearly infinite range of values found in techniques like photogravure.
Kara Walker. Testimony, 2005. Suite of 5 photogravure prints. Printed and published by the Lower East Side Printshop.
The added benefit is that photogravure is an intaglio process, where the image is etched into a copper plate and printed on an etching press. As a result, once you make a plate you have a multitude of options for how and what to print on. Fine art papers, handmade asian papers, and sepia or color tinted inks can greatly enhance the resulting prints and intensify the already velvety tones in the image.
The examples shown here are a pale simulacrum of the look and feel of photogravures seen in real life--they truly have to be seen in person to understand why this medium continues to attract artists and photographers to this day, despite the many and more immediately gratifying methods of creating and reproducing photographic imagery. The effect that the process can have on images is roughly akin to the level of intensity, detail, and focus that can be seen in daguerreotypes, but printed on paper.
Lothar Osterburg. Flat Earth, 2006
How does all of this magic happen? Learn next month at the Printshop from Lothar Osterburg, an artist, teacher, and master printer who has extensive experience in the medium and has led photogravure workshops around the country. The 4 day intensive takes place over two weekends (April 17-18 and 24-25) at the Printshop's shared artists' studio and is suitable for everyone from beginners to experienced printmakers and photographers.
The first day of the class will cover creating film positives, photo-sensitizing gelatin, and preparing copper plates, and on the second day gelatin will be exposed, adhered, and developed. The second weekend will consist of etching and printing.
Sign up for classes HERE
Additional information on the history of the process and and all around great resource is http://www.photogravure.com. Also, check out Lothar Osterburg's site at http://home.earthlink.net/~lotharosterburg/index.html