Re: separations for gum printing
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. > > >
|