Re: Fresson question
I've been studying print DMax in gum, and will eventually have a page on my site about this. I don't know about Fresson. as I've never done it and am not particularly interesting in pursuing it, so I don't know how the processes differ, but I'd agree with Sandy's characterisation of direct carbon (gum being an example of that category) as delivering a maximum DMax of around 1.4, but only as a general rule with sort of standard gum methods. DMax in gum is largely a function of pigment choice and pigment concentration, and up til recently, my conclusion has been that in a one-coat gum with something resembling a full tonal scale, 1.4 is about as much DMax as one can hope for, and that if one wants darker shadows, one must achieve them with a second printing with a heavier concentration of a pigment that can print darker (up to 1.8, such as PBk6, PBk7 or PBk11). But since seeing Marek's and Loris's experiments with bleach- development, I may have to revise that assessment; it certainly appears to be possible to get more DMax and a longer tonal scale with that method. I'm not sure how I'll test that as I haven't yet been able to make the method work for me, but it does appear to change the usual equation for gum tonal scale.
On Jan 13, 2008, at 7:06 AM, Sandy King wrote:
Reflective D-Max is just a term that describes the darkness of a print as measured with a densitometer, so it is expressed as a log value. Pt./Pd., kallitype and vandyke prints on art papers generally have a maximum Dmax of about log 1.45 - 1.55. Silver prints on glossy papers can have a Dmax of up to log 2.2 or even higher. A direct carbon print like a Fresson print will have a maximum Dmax of below log 1.4. Carbon transfer prints can have a reflective Dmax as high as silver papers, though this depends on many working conditions.