Re: curves and gum and Christopher James book
Christina, I find it very strange that a University professor finds that linearized tone mapping is hitech when it's in fact the worst approach one can use. It is as if you never eard of Tone mapping operators (Adaptive logarithmic mapping (F. Drago, 2003), Dynamic range reduction inspired by photoreceptor physiology (E. Reinhard, 2005), Gradient domain High Dynamic Range compression (R. Fattal, 2002) and others) Yves ----- Original Message ----- From: "Christina Z. Anderson" <zphoto@montana.net> To: "Alt, List" <alt-photo-process-L@usask.ca> Sent: Thursday, March 06, 2008 10:06 AM Subject: curves and gum and Christopher James book > Hi all, > I am so thrilled with Christopher James' new edition of the Book of Alt > Proc. I'm not going to go into all the reasons why, just buy it you won't > regret it. Besides, it's got 3 Judy Seigels in there as well as Dan > Burkholder's piggies and Sandy King and probably more names otherwise you > all would recognize--can't say you don't get your money's worth from the > images therein! > > Anyway, we've talked off and on about curves and gum, about different > negatives and gum, etc. etc. As we have probably always concluded, gum will > suit itself to whatever practice is chosen, and there are many ways to skin > a cat. > > Lately I have been working with a variety of negative choices to compare my > practice (tricolor seps with individual PDN derived curves and colors for > each neg) with other lesser techy ways to teach students who may not have > Photoshop or even know what a curve is. Bitmap, all ink negs, CMYK, pulling > a curve out of my butt/on the fly...I have changed my teaching practice, > even, at MSU, to start the students with all inks greyscale neg one coat gum > first, then a Sam Wang duotone negative next (greyscale, no curve, all ink > neg), then an all inks tricolor third (no curve) and finally they will do > the grandaddy of them all, making a custom curve PDN Mark Nelson tricolor. > I find that starting students out low tech and moving to high is a way to > "hook" them into the process. > > So when I saw the gum curve of Tony Gonzalez in James' book I about died. > It is hilarious. I mimicked it on my computer and found that the range of > tones he has in it go from about 26 to 92! He has essentially clipped > almost 200 tones! It looks like a flatline/dead person curve. However, > THEN look at his gum print (curve p. 351, gum p. 352-3)! The proof of > someone's working process is ALWAYS in the pudding. > > I will try Gonzalez' curve but what I bet I will find is that I have to > alter other parts of my practice to fit into the curve, whether it be > pigment load or development time or dichromate amount or exposure time or > whatnot. The reason I bring it up is that as I tell my students, gum is > really not a photographic process. If you did a curve like that with pt/pd > you'd have posterization and a gross print, but with gum which is just > hardening a layer where it needs to harden, it just isn't the same (e.g. you > can choose an exposure time of 1 min vs. 8 minutes and get a thinner or > thicker layer of hardening which is not possible with BW printing or even > pt/pd--certainly not as much variability.) And Gonzalez looks like he is > just squushing all his tones into the narrow range of stops that gum > represents, being a shorter scale process than other longer ones like pt/pd. > > It looks like Gonzalez teaches at Queens College, CUNY so if he ever has an > exhibit I would run to it. Anyone on the list know him? I wonder if he was > a student of Sarah Van Keuren's? > > So check out the book--it'll definitely spur the creative alt juices going > with the images alone, much less the information. > Chris > > > Christina Z. Anderson > Assistant Professor > Photo Option Coordinator > Montana State University > CZAphotography.com > _______________ > >
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