Comments on: Identifying the difference between a lithograph and offset print – or how I spotted few forgeries on spanish stamps http://www.stampcollectingblog.com/forgeries-of-cheap-spanish-stamps.php Amazing true stories from the life of ordinary stamp collector Fri, 12 Mar 2010 06:35:47 +0000 http://wordpress.org/?v=2.8.4 hourly 1 By: Keijo http://www.stampcollectingblog.com/forgeries-of-cheap-spanish-stamps.php#comment-1923 Keijo Fri, 04 Dec 2009 07:51:24 +0000 http://www.stampcollectingblog.com/?p=3178#comment-1923 In modern offset printing (=photogravure), the dot-pattern is always there as image is build of very tiny dots with different colors (usually CMYK). The image is etched using a photographic process (screening) onto the cylinder. This produces rows of dots, which make up the image. How visible the dots will be on final output, depends on (dot) density (which is usually 150 dots per inch or finer) and ink flow. PS. I updated the original article a bit, as I know U.S. and European terminology of printing methods tend to be slightly different. This is especially confusing as different stamp catalogs use different (and sometimes even contradicting) names for same things. In modern offset printing (=photogravure), the dot-pattern is always there as image is build of very tiny dots with different colors (usually CMYK).

The image is etched using a photographic process (screening) onto the cylinder. This produces rows of dots, which make up the image. How visible the dots will be on final output, depends on (dot) density (which is usually 150 dots per inch or finer) and ink flow.

PS. I updated the original article a bit, as I know U.S. and European terminology of printing methods tend to be slightly different. This is especially confusing as different stamp catalogs use different (and sometimes even contradicting) names for same things.

]]> By: David http://www.stampcollectingblog.com/forgeries-of-cheap-spanish-stamps.php#comment-1922 David Thu, 03 Dec 2009 15:59:16 +0000 http://www.stampcollectingblog.com/?p=3178#comment-1922 Good eye Keijo! Do you know how the dot pattern is created? Offset uses a rubber transfer plate/roller so I would expect it to be smooth. Is there a screen or mesh involved? Good eye Keijo!

Do you know how the dot pattern is created? Offset uses a rubber transfer plate/roller so I would expect it to be smooth. Is there a screen or mesh involved?

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