RE: [Digital BW] Grain drives PiezoTone mad
2002-09-26 by Jonah, Jim
This may be unrelated, however, it reminds of my days in the pre-press world trying to get smooth gradations out of Illustrator/Photoshop files. When we used a 150 lpi screen we could see the banding, but when we lowered the screen to 100 lpi the banding when away (granted it's a courser screen, but it looked better than the banding did). You mentioned that the Cone driver is imaging at 720 dpi and the Epson is at 360 dpi. In some cases a "lower" resolution is better. Not sure if this helps, but it was an eye opener when I was first learning about the differences between continuous tone and screened printing... Jim
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-----Original Message----- From: Peter Baumbach [mailto:info@...] Sent: Wednesday, September 25, 2002 8:39 PM To: DigitalBlackandWhiteThePrint@yahoogroups.com Cc: Nij; piezobw@... Subject: [Digital BW] Grain drives PiezoTone mad I am currently printing a portfolio for a friend. She photographed nudes on 35 mm Tri-X. The PiezoTone prints look posterized in the midtones (like a print that was not totally fixed) , the transitions from the midtones to the darker skin tones are much too hard. Because I just started with PiezoTone I thought it was my fault and checked everything again and again with no improvements. But today I tried Woolfs workflow and the Epson driver. And voila: the problems are solved although the highlights are not as dotfree as with the Piezo driver (under a magnifier). But thats not a problem with grainy negatives... In my opinion the holy 21 step wedge test does not show the real problems unless you are exclusively working with large format cameras and ASA 100 films or digital cameras. My assumption now is that the piezo driver has difficulties with interpreting noisy pixels. And you all can proof this if you use the 21 step wedge and add a small amount of noise that is more or less in the range of a 35 mm 400 ASA film. Then the tonal transitions being smooth when printing the step wedge straight become totally different. In the range of 35% to 50% you can find posterization, from 50% to 60% there is an artificial lumpy structure not related to the noise, from 65% to 70% again some posterization, from 70% to 100% again a too noisy lumpy structure (but less pronounced than in the 50 to 60% range). Making the same experiment with the Epson driver and Woolfs workflow does not show this phenomenon. If it is the grain that disturbs the piezo driver interpretation of density then this would explain why some people reported problems with posterization and bad skin tones and others did not mention it at all although the product is long enough in the market (btw: who tested fading before launching PiezoTone?? Should have been noticed before as well.). Any comments? Peter Baumbach Fine Art Photography Munich [Non-text portions of this message have been removed] Yahoo! Groups Sponsor ADVERTISEMENT <http://rd.yahoo.com/M=233217.2395914.3827946.2225242/D=egroupweb/S=1705 019182:HM/A=1227861/R=0/*http://ads.track-star.com/linker.ts?ts=1;2;312; 3_2_11> <http://us.adserver.yahoo.com/l?M=233217.2395914.3827946.2225242/D=egrou pmail/S=:HM/A=1227861/rand=137341529> Please visit the Group Homepage to check the Files, Bookmarks, Polls and other resources as they are often being updated. The page is at: http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint If you wish to receive no emails or just a daily digest, or you wish to unsubscribe, please edit your Membership preferences by visiting this same page. Please follow these basic guidelines: - Include your full name with your message. - Include the address of your website, if you have one. - As threads develop, trim off excess portions of earlier messages to keep them short. - As the topic of a thread changes remember to change the subject header. - Good manners are required at all time. No personal attacks or &amp;quot;flames.&amp;quot; - Complete your Yahoo profile. - Before posting a question, search the message archives and the various resources on the homepage. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> . [Non-text portions of this message have been removed]