Re: separations for gum printing
See the print made with RGB separations here: http://tinyurl.com/68cogp See a 100% crop of the 400dpi scan here: http://tinyurl.com/66b8sx Print size is exactly 8x12". As you can see I still have problems with smoothing the cyan layer. Will try the foam roller solution later. The actual print is a little bit less contrasty (enough for classifying it as "unsuccessful" IMO), the slight contrast boost is a scanning artifact. Regards, Loris. 22 Kasım 2008, Cumartesi, 2:03 am tarihinde, Loris Medici yazmış: > See the comparison here: > > http://www.loris.medici.name/gum/RGB_vs_CMY/ > (Curved negatives from RGB and CMY K=0 separations.) > > Regards, > Loris. > > > 21 Kasım 2008, Cuma, 11:09 pm tarihinde, Loris Medici yazmış: >> Hi Marek, >> >> I first planned to start to make color gums by CMYK separations -> >> because >> it seemed natural in context of "printing" + because it was the method >> used by Keith. (I had not done anything serious with gum other than few >> step tablet tests before participating his workshop...) Anyway, I >> dropped >> the idea and started with RGB separations because it required only three >> negatives, in other words less costly (1. both negative cost + less >> layers) (2. yes K=0 also requires three negatives, but I wasn't >> considering this at that time, and probably would not in the future, if >> I >> wasn't reading your message). >> >> I have an image which is currently giving me a hard time; I get perfect >> highlights and midtones but muddy / lifeless / flat shadows. I tried to >> do >> CMY K=0 separations and when I inspect the negatives on screen I see >> that >> it would print even worse, because there's no useful detail in the >> shadows. The RGB separations show good texture in the shadows, compared >> to >> the CMY separations. How come? >> >> Regards, >> Loris. >> >> P.S. I'm at my mother's house now, will post the comparison images later >> and ask for your comments. >> >> >> 20 Kasım 2008, Perşembe, 8:52 pm tarihinde, Marek Matusz yazmış: >>> ... >>> Since CMYK space and separations are intended for printmaking, which is >>> what we do in gum I started making CMY separations with K set to zero. >>> There is a visual difference on how the pictures look on screen in >>> these >>> two color spaces (anyone interested should try to toggle between spaces >>> in >>> Photosop) and also how the Y separation looks compared to B channnel in >>> RGB color space. It also seems like the colors are less muddy. I have >>> only >>> done a few pictures so far, but I want to see if anybody is doing >>> different methods of generating separations for tricolor gums.
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